WO2023038517A1 - Semicarbazone-based saponin conjugate - Google Patents

Semicarbazone-based saponin conjugate Download PDF

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Publication number
WO2023038517A1
WO2023038517A1 PCT/NL2022/050125 NL2022050125W WO2023038517A1 WO 2023038517 A1 WO2023038517 A1 WO 2023038517A1 NL 2022050125 W NL2022050125 W NL 2022050125W WO 2023038517 A1 WO2023038517 A1 WO 2023038517A1
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WIPO (PCT)
Prior art keywords
saponin
molecule
conjugate
xyl
cell
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PCT/NL2022/050125
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French (fr)
Inventor
Guy Hermans
Ruben POSTEL
Helmus VAN DE LANGEMHEEN
Mazdak ASADIAN BIRJAND
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Sapreme Technologies B.V.
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Priority claimed from PCT/NL2021/050550 external-priority patent/WO2022055352A1/en
Priority claimed from PCT/NL2022/050039 external-priority patent/WO2022164316A1/en
Application filed by Sapreme Technologies B.V. filed Critical Sapreme Technologies B.V.
Publication of WO2023038517A1 publication Critical patent/WO2023038517A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
    • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
    • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
    • A61K47/54—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic compound
    • A61K47/549—Sugars, nucleosides, nucleotides or nucleic acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H15/00—Compounds containing hydrocarbon or substituted hydrocarbon radicals directly attached to hetero atoms of saccharide radicals
    • C07H15/20—Carbocyclic rings
    • C07H15/24—Condensed ring systems having three or more rings
    • C07H15/256—Polyterpene radicals
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
    • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
    • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
    • A61K47/54—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic compound
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
    • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
    • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
    • A61K47/54—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic compound
    • A61K47/55—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic compound the modifying agent being also a pharmacologically or therapeutically active agent, i.e. the entire conjugate being a codrug, i.e. a dimer, oligomer or polymer of pharmacologically or therapeutically active compounds

Definitions

  • the invention relates to a saponin derivative based on a saponin comprising a triterpene aglycone and at least one saccharide chain linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde functional group which has been transformed to a semicarbazone functional group.
  • the invention also relates to a first pharmaceutical composition comprising the saponin derivative of the invention.
  • the invention relates to a pharmaceutical combination
  • a pharmaceutical combination comprising the first pharmaceutical composition of the invention and a second pharmaceutical composition comprising a conjugate of a cell-surface molecule binding-molecule and an effector moiety, such as any one or more of an antibody-effector moiety conjugate, an receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-nucleic acid conjugate or a receptor-ligand – nucleic acid conjugate (such as a receptor-ligand – oligonucleotide conjugate, wherein for example the oligonucleotide is an AON such as a BNA or an siRNA, and wherein the receptor ligand is for example EGF or at least one GalNAc moiety).
  • an antibody-effector moiety conjugate such as any one or more of an antibody-effector moiety conjugate,
  • the invention also relates to the first pharmaceutical composition or the therapeutic combination comprising the first pharmaceutical composition of the invention, for use as a medicament, or for use in the treatment or prophylaxis of a cancer or an auto-immune disease or a cardiovascular disease or hypercholesterolemia, or for use in a method for decreasing the level of LDL, preferably LDL-cholesterol, in the blood of a subject.
  • the invention relates to an in vitro or ex vivo method for transferring a molecule such as an effector molecule or, when part of a conjugate, an effector moiety, from outside a cell to inside said cell, comprising contacting said cell with the molecule and with a saponin derivative of the invention.
  • the invention also relates to a saponin conjugate comprising a cell-surface molecule binding-molecule such as a proteinaceous molecule or a non-proteinaceous molecule such as a receptor-ligand such as at least one GalNAc moiety, capable of binding to said cell, covalently bound to the saponin, wherein the saponin conjugate is based on the saponin derivative of the invention.
  • a cell-surface molecule binding-molecule such as a proteinaceous molecule or a non-proteinaceous molecule such as a receptor-ligand such as at least one GalNAc moiety
  • the invention also relates to a pharmaceutical combination comprising a third pharmaceutical composition comprising the saponin conjugate of the invention and a fourth pharmaceutical composition comprising an active pharmaceutical ingredient such as a conjugate of a cell-surface molecule binding-molecule and an effector moiety, for example an ADC or an AOC or a conjugate of a receptor ligand, such as at least one GalNAc moiety, and an oligonucleotide, or the invention also relates to a pharmaceutical composition comprising the saponin conjugate of the invention and a conjugate of a cell-surface molecule binding-molecule and an effector moiety such as a conjugate of a receptor ligand, such as at least one GalNAc moiety, and an oligonucleotide.
  • an active pharmaceutical ingredient such as a conjugate of a cell-surface molecule binding-molecule and an effector moiety
  • an ADC or an AOC or a conjugate of a receptor ligand such as at least one GalNAc moiety
  • the invention relates to the pharmaceutical combination of the invention or the pharmaceutical composition of the invention, for use as a medicament, or for use in the treatment or the prophylaxis of a cancer or an auto-immune disease or a cardiovascular disease or hypercholesterolemia, or for use in a method for decreasing the level of LDL-cholesterol in the blood of a subject.
  • the invention also relates to a saponin derivative in which at least one GalNAc moiety, an oligonucleotide and at least one saponin molecule are covalently bound together, wherein the saponin derivative is based on a saponin comprising a triterpene aglycone and at least one saccharide chain linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde functional group which has been transformed to a semicarbazone functional group (also referred to as ‘semicarbazone bond’).
  • An aspect of the invention relates to the saponin derivative encompassing GalNAc, an oligonucleotide and one or more saponin moieties, for use as a medicament or for use in a method for the treatment or prophylaxis of a cardiovascular disease or hypercholesterolemia, or for use in a method for lowering LDL-cholesterol in the blood of a subject.
  • BACKGROUND OF THE INVENTION Targeted tumor therapy is a cancer treatment that uses drugs to target specific genes and proteins that are involved in the growth and survival of cancer cells.
  • Immunotoxins which are targeted toxins that contain an antibody as targeting moiety, are very promising because they combine the specificity of an antibody against tumor-specific antigens, which enables them to channel the toxin to the aimed point of action and can introduce additionally cell killing mechanisms such as antibody- dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity. To exhibit its effect, the toxin needs to be released into the cytosol after internalization.
  • a major drawback is that the targeting moiety which bears the payload is often not fully internalized, directly recycled to the surface after internalization, or degraded in lysosomes, therewith hampering the sufficient delivery of the payload into the cell cytosol.
  • glycosylated triterpenes such as saponins were found to act as endosomal escape enhancers for targeted toxins, such as ribosome-inactivating proteins (RIPs), in tumor therapy.
  • Formula (1) Especially, saponin SO1861 (Formula (2), sometimes also referred to as SPT001 or SPT1 or SPT), a triterpenoid saponin, was identified as a potent enhancer of the endosomal escape of tumor-cell targeted toxins.
  • a dual effect for the enhancer mechanism is postulated: first, a direct increase of the endosomal escape resulting in caspase-dependent apoptosis that is, second, combined with lysosomal-mediated cell death pathways, which are triggered after the release of cathepsins and other hydrolytic enzymes following destruction of lysosomal membranes.
  • saponins themselves, including the structure of the triterpene backbone, a pentacyclic C30 terpene skeleton (also known as sapogenin or aglycone), number and length of saccharide side chains as well as type and linkage variants of the sugar residues linked to the backbone, contribute to the hemolytic potential and/or cytotoxicity of such saponins.
  • the saponins per se are not target-specific when the endosome and the cytosol of cells are considered, and saponins expectedly and most often distribute in a (human) subject with other kinetics than the targeted toxins, even when the same route of administration would be considered for a combination of a saponin and e.g. an ADC.
  • the saponin molecules can be found in any organ, implying that specificity is only mediated by the targeted toxin.
  • Distribution of saponins in the whole body requires higher concentrations for a successful treatment when compared to specific accumulation in target cells as is achieved for the ADC.
  • the toxicity of the modified saponins needs to be low enough for a successful application in view of the systemic application of saponins in the body, in order to achieve a suitable therapeutic window. Therefore, there is a still a need to improve the therapeutic index when co-administration of a saponin together with e.g.
  • an ADC need for better controlling (or better: lowering) the cytotoxicity of saponins while at the same time maintaining sufficient efficacy when potentiation of the cytotoxic effect of an ADC is considered.
  • ADCs are mainly composed of an antibody, a cytotoxic moiety such as a payload, and a linker.
  • the antibody component by identification and validation of adequate antigenic targets for the antibody component, by selecting antigens which have high expression levels in tumor and little or no expression in normal tissues, antigens which are present on the cell surface to be accessible to the circulating ADCs, and antigens which allow internalizing of ADCs into the cell after binding; and alternative mechanisms of activity; design and optimize linkers which enhance the solubility and the drug-to- antibody ratio (DAR) of ADCs and overcome resistance induced by proteins that can transport the chemotherapeutic agent out of the cells; enhance the DAR ratio by inclusion of more payloads, select and optimize antibodies to improve antibody homogeneity and developability.
  • DAR drug-to- antibody ratio
  • ADCs In addition to the technological development of ADCs, new clinical and translational strategies are also being deployed to maximize the therapeutic index, such as, change dosing schedules through fractionated dosing; perform bio-distribution studies; include biomarkers to optimize patient selection, to capture response signals early and monitor the duration and depth of response, and to inform combination studies.
  • An example of ADCs with clinical potential are those ADCs such as brentuximab vedotin, inotuzumab ozogamicin, moxetumomab pasudotox, and polatuzumab vedotin, which are evaluated as a treatment option for lymphoid malignancies and multiple myeloma.
  • Polatuzumab vedotin, binding to CD79b on (malignant) B-cells, and pinatuzumab vedotin, binding to CD22 are tested in clinical trials wherein each ADC was combined with co-administered rituximab, a monoclonal antibody binding to CD20 and not provided with a payload [B. Yu and D. Liu, Antibody-drug conjugates in clinical trials for lymphoid malignancies and multiple myeloma; Journal of Hematology & Oncology (2019) 12:94].
  • nucleic acid-based therapeutics can be based on deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), in the form of anti-sense oligonucleotides (ASOs, AONs), and short interfering RNAs (siRNAs), microRNAs, and DNA and RNA aptamers, RNA interference (RNAi), and for approaches such as gene therapy.
  • DNA deoxyribonucleic acid
  • RNA ribonucleic acid
  • ASOs, AONs anti-sense oligonucleotides
  • siRNAs short interfering RNAs
  • microRNAs microRNAs
  • DNA and RNA aptamers DNA and RNA aptamers
  • RNAi RNA interference
  • ASOs such as peptide nucleic acid (PNA), phosphoramidate morpholino oligomer (PMO), locked nucleic acid (LNA) and other bridged nucleic acids (BNA) are being investigated as an attractive strategy to inhibit specifically target genes and especially those genes that are difficult to target with small molecule inhibitors or neutralizing antibodies.
  • PNA peptide nucleic acid
  • PMO phosphoramidate morpholino oligomer
  • LNA locked nucleic acid
  • BNA bridged nucleic acids
  • Scaffold-small-molecule drug conjugates such as polymer-drug conjugates (PDCs) are macromolecular constructs with pharmacologically activity, which comprises one or more molecules of a small-molecule drug bound to a carrier scaffold (e.g., polyethylene glycol (PEG)).
  • PEG polyethylene glycol
  • Such conjugate principle has attracted much attention and has been under investigation for several decades. The majority of conjugates of small-molecule drugs under pre-clinical or clinical development are for oncological indications. However, to this date only one drug not related to cancer has been approved in 2014 (Movantik, a PEG oligomer conjugate of opioid antagonist naloxone, AstraZeneca) for opioid-induced constipation in patients with chronic pain.
  • PK1 N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer doxorubicin; development by Pharmacia, Pfizer
  • HPMA 2-hydroxypropyl)methacrylamide copolymer doxorubicin
  • Liposomes are sphere-shaped vesicles consisting of one or more phospholipid bilayers, which are spontaneously formed when phospholipids are dispersed in water.
  • the amphiphilicity characteristics of the phospholipids provide it with the properties of self- assembly, emulsifying and wetting characteristics, and these properties can be employed in the design of new drugs and new drug delivery systems.
  • Drug encapsulated in a liposomal delivery system may convey several advantages over a direct administration of the drug, such as an improvement and control over pharmacokinetics and pharmacodynamics, tissue targeting property, decreased toxicity and enhanced drug activity. Examples of such successes are liposome- encapsulated forms of a small molecule chemotherapy agent doxorubicin (Doxil: a pegylated liposome-encapsulated form of doxorubicin; Myocet: a non-pegylated liposomal doxorubicin), which have been approved for clinical use.
  • doxorubicin Doxil: a pegylated liposome-encapsulated form of doxorubicin
  • Myocet a non-pegylated liposomal doxorubicin
  • X O, P or S
  • saponin derivatives have one or more of the following benefits: i) a reduced toxicity when cell viability is considered of cells contacted with the saponin derivatives, ii) increased activity when potentiation of an effector moiety, e.g. toxin cytotoxicity or AON (e.g. BNA) mediated gene silencing, is considered (without wishing to be bound by any theory: relating to similar or improved endosomal escape enhancing activity of the modified saponin) and/or iii) reduced hemolytic activity, when compared with the toxicity, activity and haemolytic activity of unmodified saponin (non- derivatized saponin).
  • an effector moiety e.g. toxin cytotoxicity or AON (e.g. BNA) mediated gene silencing
  • the inventors provide saponin derivatives with an improved therapeutic window, since the ratio between IC50 values for cell toxicity and e.g. IC50 values for toxin potentiation or IC50 values for gene silencing is increased, and/or since the ratio between IC50 values for saponin haemolytic activity and e.g. IC50 values for toxin potentiation or IC50 values for gene silencing is increased.
  • the inventors surprisingly established (tumor) cell killing by contacting such cells with a saponin conjugate of the current invention based on a saponin derivative of the current invention e.g.
  • a ligand such as an antibody or a GalNAc moiety
  • a cell-surface molecule such as a receptor such as ASGPR (when the ligand is at least one GalNAc moiety in the saponin conjugate)
  • an ADC such as an antibody – protein toxin conjugate or a conjugate comprising a GalNAc moiety and an oligonucleotide, despite the medium to low expression of the cell-surface receptor targeted by the cell-surface molecule binding-molecule (e.g. antibody, one or more GalNAc moieties) comprised by the saponin conjugate and/or despite the medium to low expression of the cell-surface receptor targeted by the ADC or by the GalNAc/oligonucleotide conjugate.
  • the saponin derivative and the saponin conjugate of the invention comprise the semicarbazone functional group.
  • the inventors now provide for a more potent saponin derivative and saponin conjugate, when the activation or potentiating of an effector moiety such as an effector moiety comprised by an ADC or AOC or comprised by a GalNAc/oligonucleotide conjugate, is considered.
  • the saponin conjugate of the invention is based on a saponin derivative of the invention and comprising an oligonucleotide, wherein the oligonucleotide comprised by said saponin conjugate is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt.
  • the saponin conjugate further comprises a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme), and/or further comprises a non-proteinaceous molecule such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme).
  • a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme)
  • a non-proteinaceous molecule such as one or more GalNAc
  • This has the benefit that a lower amount of the saponin derivatives according to the invention should be administered to a patient in need of potentiation of e.g.
  • faster release of the saponin comprising the aldehyde functional group from the saponin derivative that comprises the semicarbazone functional group according to the invention when compared to release of the saponin comprising the aldehyde functional group from the saponin derivative that comprises the hydrazone functional group, is at the basis for the improved activity of the saponin conjugate of the invention comprising a saponin derivative of the invention, wherein the activity is the potentiation of the effector moiety activity inside the cytosol or nucleus of the targeted cell by endosomal escape enhancement.
  • the saponin derivative according to the invention wherein the saponin on which the saponin derivative is based is a monodesmosidic or bi-desmosidic triterpene saponin belonging to the type of a 12,13-dehydrooleanane with the aldehyde group in position C-23 and optionally comprising a glucuronic acid group in a carbohydrate substituent at the C-3beta-OH group of the saponin, preferably a bi-desmosidic triterpene saponin belonging to the type of a 12,13- dehydrooleanane with the aldehyde group in position C-23 and comprising a glucuronic acid group in a carbohydrate substituent at the C-3beta-OH group of the saponin.
  • X O.
  • An embodiment is the saponin derivative of the invention, wherein the saponin on which the saponin derivative is based is any one or more of: a) saponin selected from any one or more of list A: - Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; - Gypsophila elegans saponin mixture, or a saponin isolated from Gypsophila elegans; - Saponinum album saponin mixture, or a saponin isolated from Saponinum album; - Saponaria officinalis saponin mixture, or a saponin isolated from Saponaria officinalis; and - Quillaja bark saponin mixture, or a saponin isolated from Quillaja bark, for example Quil- A, QS-17-api,
  • An embodiment is the saponin derivative of the invention, wherein the saponin (on which the saponin derivative is based) is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS-7, SA1641, a saponin isolated from Saponaria officinalis, Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; preferably wherein the saponin is any one or more of QS- 21, SO1832, SO1861, SA1641 and GE1741; more preferably wherein the saponin is QS-21, SO1832 or SO1861; most preferably being SO1861.
  • the saponin is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS-7, SA1641, a sap
  • An embodiment is the saponin derivative of the invention, wherein the saponin (on which the saponin derivative is based) is a saponin isolated from Saponaria officinalis, preferably wherein the saponin is any one or more of Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; more preferably wherein the saponin is any one or more of SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; even more preferably wherein the saponin is any one or more of SO1832, SO1861 and SO1862; even more preferably wherein the saponin is SO1832 and SO1861; most preferably being SO1861.
  • a saponin derivative according to the invention is the saponin derivative according to molecule (AA):
  • SM saponin moiety according to formula (SM): , wherein R 1 and R 2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23.
  • the saponin derivative of molecule (AA) is based on SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861.
  • a saponin derivative according to the invention is the saponin derivative according to molecule (BB): , which molecule (BB) is the covalent conjugation product obtained by the covalent conjugation of the saponin derivative according to molecule (AA) with the tri-functional linker according to formula (XXI):
  • the saponin derivative of molecule (BB) is based on SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861.
  • a saponin conjugate according to the invention is the saponin conjugate according to molecule (CC):
  • molecule (CC) is the covalent conjugation product obtained by the covalent conjugation of the tri-functional linker according to formula (XXI) with the saponin derivative according to molecule (AA) and with GalNAc conjugate according to molecule (FF): , wherein represents the tri-GalNAc conjugate according to molecule (DD1) or according to molecule (DD2):
  • y1, y2 and y3 each are an integer independently selected from 0-20, preferably 1-15, more preferably 2-12, even more preferably 2-10, even more preferably 2-8, most preferably 2 and 3, and preferably y1, y2 and y3 are the same, and y4 is an integer selected from 1-100, preferably 2-80, more preferably 3-70, even more preferably 4-60, even more preferably 4-50, even more preferably 4-40, even more preferably 4-30, even more preferably 4-20, even more preferably 4-6, most preferably 3-5, such as 4;
  • x1, x2 and x3 each are an integer independently selected from 0-20, preferably 1-15, more preferably 2-12, even more preferably 2-10, even more preferably 2-8, most preferably 2 and 3, and preferably x1, x2 and x3 are the same, and x4 is an integer selected from 1-50, preferably 2-40, more preferably 3-30, even more preferably 4-20, even more preferably 5-15, most preferably 8- 12, such as 9, and preferably represents the tri-GalNAc conjugate according to molecule (DD3) or according to molecule (DD4):
  • the saponin conjugate of molecule is based on saponin SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861.
  • a saponin conjugate according to the invention is the saponin conjugate according to molecule (EE):
  • molecule (EE) is the covalent conjugation product obtained by the covalent conjugation of the tri-functional linker according to formula (XXI) with the saponin derivative according to molecule (AA) and with GalNAc conjugate according to molecule (FF) and with the oligonucleotide provided with a linker according to molecule (GG): , wherein the molecule (GG) represents the conjugation product of the conjugation reaction between the linker (E)-1-(4-((2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)hexanoyl)hydrazineylidene)methyl)benzamido)-N-(4-(6-methyl-1,2,4,5-tetrazin-3-yl)benzyl)- 3,6,9,12-tetraoxapentadecan-15-amide and the oligonucleotide-linker molecule according to molecule (HH):
  • the oligonucleotide of molecule (EE) is an AON such as a BNA or an siRNA.
  • the oligonucleotide of molecule (EE) is a BNA, for example a BNA for silencing HSP27 expression or apoB expression, preferably in a human cell.
  • a saponin derivative according to the invention is the saponin derivative according to molecule (JJ): which molecule (JJ) is the conjugate product of conjugation of N,N'-((9S,19S)-14-(6- aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo-4,11,14,17- tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide first with saponin derivative according to molecule (KK): and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate , wherein represents a saponin moiety according to formula (SM).
  • SM saponin moiety according to formula (SM).
  • the saponin derivative of molecule (JJ) is based on SO1861, SO1832 or QS- 21, more preferably SO1861 or SO1832, most preferably SO1861.
  • a saponin conjugate according to the invention is the saponin conjugate according to molecule (LL):
  • LL which molecule (LL) is the covalent conjugation product obtained by the covalent conjugation of the molecule (JJ) with the conjugate of the tri-functional linker and GalNAc according to molecule (MM):
  • molecule (MM) is the conjugate of the tri-functional linker according to formula (XXI) and the GalNAc conjugate according to molecule (NN): , wherein represents the tri-GalNAc conjugate according to molecule (DD1) or molecule (DD2), preferably molecule (DD3) or molecule (DD4), more preferably molecule (DD3) as detailed here above.
  • a saponin conjugate according to the invention is the saponin conjugate according to molecule (PP): ed i t o e l cunog i l o , which molecule (PP) is the covalent conjugation product obtained by the covalent conjugation of the molecule (LL) with the oligonucleotide provided with a linker according to molecule (GG).
  • a saponin derivative according to the invention is the saponin derivative according to molecule (QQ):
  • the saponin derivative of molecule is based on SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861.
  • a saponin conjugate according to the invention is the saponin conjugate according to molecule (RR):
  • a saponin conjugate according to the invention is the saponin conjugate according to molecule (SS):
  • SS which molecule (SS) is the covalent conjugation product obtained by the covalent conjugation of the molecule (RR) with the oligonucleotide provided with a linker according to molecule (GG).
  • the saponin derivatives of molecule (JJ) and molecule (QQ) and/or the saponin conjugates of molecules (LL), (PP), (RR) and/or (SS) is/are based on saponin SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861.
  • the oligonucleotide of molecule (PP) and/or of molecule (SS) is/are an AON such as a BNA or an siRNA.
  • the oligonucleotide of molecule (SS) is a BNA, for example a BNA for silencing HSP27 expression or apoB expression, preferably in a human cell.
  • An aspect of the invention relates to a ninth pharmaceutical composition comprising any one of the conjugates according to molecules (LL), (PP), (RR) and (SS).
  • An aspect of the invention relates to the ninth pharmaceutical composition comprising any one of the conjugates according to molecules (LL), (PP), (RR) and (SS) or to any one of the conjugates according to molecules (LL), (PP), (RR) and (SS), for use as a medicament.
  • An aspect of the invention relates to the ninth pharmaceutical composition
  • the ninth pharmaceutical composition comprising any one of the conjugates according molecules (LL), (PP), (RR) and (SS) or to any one of the conjugates according to molecules (LL), (PP), (RR) and (SS), for use in the treatment or prophylaxis of a cancer, an infectious disease, a viral infection, hypercholesterolemia, cardiovascular disease, primary hyperoxaluria, haemophilia A, haemophilia B, AAT related liver disease, acute hepatic porphyria, TTR-mediated amyloidosis, hereditary TTR amyloidosis (hATTR), complement- mediated disease, hepatitis B infection, hepatitis C infection, ⁇ 1-antitrypsin deficiency, ⁇ - thalassaemia, or an auto-immune disease.
  • An aspect of the invention relates to the ninth pharmaceutical composition comprising any one of the conjugates according to molecules (LL), (PP), (RR) and (SS) or to any one of the conjugates according to molecules (LL), (PP), (RR) and (SS), for use in the lowering of LDL- cholesterol in a subject.
  • R 1 is selected from: H, GlcA-, Glc-, Gal-, Rha-(1 ⁇ 2)-Ara-, Gal-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)]-GlcA-, Glc-(1 ⁇ 2)-[Glc-(1 ⁇ 4)]-GlcA-, Glc-(1 ⁇ 2)-Ara-(1 ⁇ 3)-[Gal-(1 ⁇ 2)]-GlcA-, Xyl-(1 ⁇ 2)-Ara-(1 ⁇ 3)-[Gal-(1 ⁇ 2)]-GlcA-, Glc-(1 ⁇ 3)-Gal-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)]-Glc-(1 ⁇ 4)-Gal-, Rha-(1 ⁇ 2)-Gal-(1 ⁇ 3)-[Glc-(1 ⁇ 2)]-GlcA-, Ara-(1 ⁇ 2)-Gal-(1 ⁇ 3)-[Glc-(1 ⁇ 2)]
  • R 1 is Gal-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)]-GlcA-; and R 2 is selected from: Glc-(1 ⁇ 3)-Xyl-(1 ⁇ 4)-Rha-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)-4-OAc-Qui-(1 ⁇ 4)]-Fuc-, Xyl-(1 ⁇ 3)-Xyl-(1 ⁇ 4)-Rha-(1 ⁇ 2)-[3,4-di-OAc-Qui-(1 ⁇ 4)]-Fuc-, Api-(1 ⁇ 3)-Xyl-(1 ⁇ 4)-Rha-(1 ⁇ 2)-[R 12 -( ⁇ 4)]-Fuc- wherein R 12 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-oct
  • the saponin derivative is a derivative of a saponin selected from the group of saponins consisting of: Quillaja bark saponin, dipsacoside B, saikosaponin A, saikosaponin D, macranthoidin A, esculentoside A, phytolaccagenin, aescinate, AS6.2, NP-005236, AMA-1, AMR, alpha-Hederin, NP-012672, NP- 017777, NP-017778, NP-017774, NP-018110, NP-017772, NP-018109, NP-017888, NP-017889, NP-018108, SA1641, AE X55, NP-017674, NP-017810, AG1, NP-003881, NP-017676, NP- 017677, NP-017706, NP-017705, NP-017773, NP-017775, SA1657, AG2,
  • saponin derivative according to the invention which is a derivative of SO1861, SO1832 or QS-21, preferably SO1861 and SO1832.
  • saponin derivative is according to formula (V), formula (VI), formula (VII) or formula (VIII):
  • the saponin derivative is according to formula (V), formula (VII) or formula (VIII), more preferably wherein the saponin derivative is according to formula (V) or formula (VIII), most preferably according to formula (VIII).
  • Preferred is a saponin derivative of the invention, wherein the saponin derivative is according to molecule (V), molecule (VII) or molecule (VIII):
  • An aspect of the invention relates to a first pharmaceutical composition comprising the saponin derivative according to the invention and optionally a pharmaceutically acceptable excipient and/or diluent.
  • An aspect of the invention relates to a first pharmaceutical combination comprising: (a) the first pharmaceutical composition of the invention; and (b) a second pharmaceutical composition comprising a conjugate of a cell-surface molecule binding-molecule and an effector moiety, wherein the cell-surface molecule binding-molecule is a proteinaceous molecule such as an antibody, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • An aspect of the invention relates to a first pharmaceutical combination comprising: (a) the first pharmaceutical composition of the invention; and (b) a second pharmaceutical composition comprising any one or more of: a conjugate of a cell- surface molecule binding-molecule and an effector moiety, an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-oligonucleotide conjugate, and a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • An aspect of the invention relates to a third pharmaceutical composition
  • a third pharmaceutical composition comprising the saponin derivative of the invention and further comprising a conjugate of a cell-surface molecule binding- molecule and an effector moiety, wherein the cell-surface molecule binding-molecule is a proteinaceous molecule such as an antibody, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • An aspect of the invention relates to a third pharmaceutical composition
  • a conjugate of a cell-surface molecule binding-molecule and an effector moiety comprising any one or more of: a conjugate of a cell-surface molecule binding-molecule and an effector moiety, an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody- oligonucleotide conjugate and a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • An embodiment is the first pharmaceutical combination comprising the second pharmaceutical composition of the invention, or the third pharmaceutical composition of the invention, wherein the second pharmaceutical composition or the third pharmaceutical composition comprises any one or more of an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody- oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, wherein preferably the toxin is a protein toxin.
  • Preferred is the first pharmaceutical combination comprising the first pharmaceutical composition of the invention, or the third pharmaceutical composition of the invention, wherein the saponin derivative is any one or more of the saponin derivatives according to the invention.
  • An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use as a medicament.
  • An aspect of the invention relates to the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use as a medicament.
  • An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cancer or an auto-immune disease.
  • An aspect of the invention relates to the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cancer or an auto-immune disease.
  • An aspect of the invention relates to the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cardiovascular disease or of hypercholesterolemia, or for use in a method for lowering LDL-cholesterol in the blood of a subject, preferably a human subject.
  • suitable target cell-surface receptors to which the saponin conjugate of the invention can bind are: HER2, EGFR and CD71. Therefore, these targets are preferred. More preferred is CD71.
  • An aspect of the invention relates to the first pharmaceutical combination of the invention, the second pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, or to the 1-component saponin conjugate of the invention, for use according to the invention, i.e., for use in the treatment or prevention of a disease or health problem related to presence of a diseased cell according to the invention, for use in the treatment or prevention of a disease or health problem related to the presence of the aberrant cell according to the invention, for use in the treatment or prevention of a cancer, and/or for use in the treatment or prevention of an autoimmune disease, preferably in a human patient, wherein the first cell surface molecule and the third cell surface molecule are CD71 and/or the second cell surface molecule is CD71, and/or the first proteinaceous molecule and the third proteinaceous molecule are a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the second proteinaceous molecule is a monoclonal antibody capable of binding to CD71
  • An aspect of the invention relates to an in vitro or ex vivo method for transferring a molecule from outside a cell to inside said cell, preferably into the cytosol of said cell, comprising the steps of: a) providing a cell; b) providing the molecule for transferring from outside the cell into the cell provided in step a); c) providing a saponin derivative according to the invention; d) contacting the cell of step a) in vitro or ex vivo with the molecule of step b) and the saponin derivative of step c), therewith establishing the transfer of the molecule from outside the cell into said cell.
  • An aspect of the invention relates to a saponin conjugate based on a saponin derivative according to the invention, wherein the aldehyde group (of the saponin) is transformed into a semicarbazone functional group according to formula (IX) wherein n and m each are an integer independently selected from 1, 2, or 3; o is an integer selected from 0-10, preferably 2-7, more preferably 4-6; and wherein the maleimide functional group is further transformed into a thioether bond through reaction with a first proteinaceous molecule (‘proteinaceous molecule 1’) comprising a thiol functional group according to formula (X)
  • a preferred saponin conjugate according to the invention is the saponin conjugate according to formula (XI) wherein R 1 and R 2 are as defined in any one of claims 1-10; n and m each are an integer independently selected from 1, 2 or 3; and o is an integer selected from 0-10, preferably 2-7, more preferably 4-6.
  • Preferred is the saponin conjugate according to the invention, wherein the saponin conjugate is according to formula (XII)
  • the saponin conjugate according to the invention wherein the proteinaceous molecule 1 comprises a covalently bound effector moiety.
  • the saponin conjugate according to the invention wherein the effector moiety is an oligonucleotide.
  • the saponin conjugate comprises the proteinaceous molecule 1 and an oligonucleotide.
  • the saponin conjugate of the invention based on a saponin derivative of the invention and comprising an oligonucleotide, wherein the oligonucleotide comprised by said saponin conjugate is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt.
  • the saponin conjugate further comprises a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme), and/or further comprises a non-proteinaceous molecule such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme).
  • a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme)
  • a non-proteinaceous molecule such as one or more GalNAc
  • the saponin conjugate of the invention based on a saponin derivative of the invention, wherein the proteinaceous molecule 1 comprised by the saponin conjugate is covalently bound to an oligonucleotide, wherein preferably the oligonucleotide is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt.
  • An aspect of the invention relates to an eighth pharmaceutical composition
  • the saponin conjugate which comprises the proteinaceous molecule 1 comprising a covalently bound effector moiety, preferably an oligonucleotide, and optionally a pharmaceutically acceptable excipient and/or diluent.
  • An aspect of the invention relates to the eighth pharmaceutical composition for use as a medicament.
  • the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule.
  • a typical saponin conjugate of the invention is the saponin conjugate, wherein the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule, wherein said first binding site is or comprises any one or more of: an amino acid, a peptide, a protein, an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, a ligand for a cell-surface molecule such as a receptor such as EGF or a cytokine.
  • sdAb single-domain antibody
  • the antibodies (immunoglobulins) of the present invention may be bi- or multifunctional.
  • a bifunctional antibody has one arm having a specificity for one receptor or antigen, while the other arm recognizes a different receptor or antigen.
  • each arm of the bifunctional antibody may have specificity for a different epitope of the same receptor or antigen of the target cell.
  • the antibodies (immunoglobulins) of the present invention may be, but are not limited to, polyclonal antibodies, monoclonal antibodies, human antibodies, humanized antibodies, chimeric antibodies, resurfaced antibodies, anti-idiotypic antibodies, mouse antibodies, rat antibodies, rat/mouse hybrid antibodies, llama antibodies, llama heavy-chain only antibodies, heavy-chain only antibodies, and veterinary antibodies.
  • the antibody (immunoglobulin) of the present invention is a monoclonal antibody.
  • the resurfaced, chimeric, humanized and fully human antibodies are also more preferred because they are less likely to cause immunogenicity in humans.
  • the antibodies of the ADC of the present invention preferably specifically binds to an antigen expressed on the surface of a cancer cell, an autoimmune cell, a diseased cell, an aberrant cell, while leaving any healthy cell essentially unaltered (e.g., by not binding to such normal cell, or by binding to a lesser extent in number and/or affinity to such healthy cell).
  • a preferred embodiment is the saponin conjugate according to the invention, wherein the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule, wherein said first binding site is or comprises any one or more of: a single-domain antibody (sdAb), preferably a VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VHH domain such as derived from a heavy-chain only antibody (HCAb) such as from Camelidae origin or Ig-NAR origin such as a variable heavy chain new antigen receptor (VNAR) domain, preferably the HCAb is from Camelidae origin, preferably the sdAb is a VHH domain derived from an HCAb from Camelidae origin (camelid
  • the first epitope of the first cell-surface molecule, to which the proteinaceous molecule 1 can preferably bind is a tumor-cell specific first epitope of a first tumor-cell surface molecule, more preferably a tumor-cell specific first epitope of a first tumor-cell surface receptor specifically present on a tumor cell.
  • An embodiment is the saponin conjugate of the invention, based on the saponin derivative of the invention, wherein the first cell surface molecule is a first cell surface receptor, preferably an endocytic cell-surface receptor, preferably a diseased cell specific receptor or an aberrant cell specific receptor or a tumor-cell specific receptor, or a receptor overexpressed at a diseased cell, aberrant cell or tumor cell, more preferably the cell surface molecule is selected from any one or more of: CD71, CA125, EpCAM(17-1A), CD52, CEA, CD44v6, FAP, EGF-IR, integrin, syndecan-1, vascular integrin alpha-V beta-3, HER2, EGFR, CD20, CD22, Folate receptor 1, CD146, CD56, CD19, CD138, CD27L receptor, prostate specific membrane antigen (PSMA), CanAg, integrin- alphaV, CA6, CD33, mesothelin, Cripto, CD3, CD30, CD239, CD70, CD123
  • An embodiment is the saponin conjugate of the invention, comprising an antibody, based on the saponin derivative of the invention, wherein the antibody is selected from, or the sdAb is derived from or based on, any one or more of immunoglobulins: an anti-CD71 antibody such as IgG type OKT-9, an anti-HER2 antibody such as trastuzumab (Herceptin), pertuzumab, an anti-CD20 antibody such as rituximab, ofatumumab, tositumomab, obinutuzumab ibritumomab, an anti-CA125 antibody such as oregovomab, an anti-EpCAM (17-1A) antibody such as edrecolomab, an anti- EGFR antibody such as cetuximab, matuzumab, panitumumab, nimotuzumab, an anti-CD30 antibody such as brentuximab, an anti-CD33 antibody such as gemt
  • the semicarbazone functional group is hydrolysable (cleavable) under acidic conditions, preferably at pH 4.0 – 6.5, wherein hydrolysis of said semicarbazone functional group provides the aldehyde group on the aglycone core structure of the saponin on which the saponin derivative is based.
  • a specifically preferred embodiment is the saponin derivative according to the invention and/or the saponin conjugate according to the invention, wherein the semicarbazone functional group is subject to hydrolysis in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ⁇ 5.5.
  • the saponin derivatives according to the invention which are used as a component for potentiating the intracellular effect of an effector molecule or effector moiety when the effector molecule is provided as a conjugate comprising a cell-surface molecule binding-molecule such as an antibody, e.g.
  • an ADC or AOC are now also suitably for (covalent) coupling to a cell-surface molecule binding-molecule such as a cell-surface molecule targeting antibody, such as an sdAb, such that by such coupling the saponin conjugate of the invention is provided, endowed with, for example, anti-tumor activity potentiating activity when used in combination with for example an ADC or an AOC.
  • a cell-surface molecule binding-molecule such as a cell-surface molecule targeting antibody, such as an sdAb
  • An aspect of the invention relates to a second pharmaceutical combination comprising: (a) a fourth pharmaceutical composition comprising the saponin conjugate of the invention and optionally a pharmaceutically acceptable excipient and/or diluent; and (b) a fifth pharmaceutical composition comprising a conjugate comprising a cell- surface molecule binding-molecule, such as a second proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety, wherein the proteinaceous molecule 2 is the same or different from the proteinaceous molecule 1 present in the saponin conjugate, and if the proteinaceous molecule 2 is different from the proteinaceous molecule 1, the proteinaceous molecule 2 comprising a second binding site for binding to a second epitope of a second cell-surface molecule, wherein the second cell-surface molecule is the same as or different from the first cell surface molecule, and if the second cell-surface molecule is different from the first cell surface molecule, the second cell-surface molecule and the first cell surface molecule are preferably
  • the effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based.
  • the effector moiety is not the saponin derivative or the saponin conjugate of the invention.
  • An embodiment is the second pharmaceutical combination of the invention, comprising: (a) the fourth pharmaceutical composition of the invention comprising the saponin conjugate of the invention, wherein the first epitope on the first cell-surface molecule is a tumor-cell specific first epitope on a first tumor cell-specific surface molecule, preferably a tumor-cell specific first epitope on a first cell-surface receptor specifically present at a tumor cell; and (b) the fifth pharmaceutical composition of the invention, wherein the second cell-surface molecule is a second tumor cell-specific surface molecule which is the same or different from the first tumor cell-specific surface molecule, preferably a second cell-surface receptor specifically present at a tumor cell which is the same or different from the first cell-surface receptor specifically present at said tumor cell, and wherein the second epitop
  • An aspect of the invention relates to a third pharmaceutical combination, comprising: (a) the fourth pharmaceutical composition of the invention comprising the saponin conjugate according to the invention, comprising the first binding site for binding to the first epitope on the first cell-surface molecule, the fourth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent; and (b) a sixth pharmaceutical composition comprising a conjugate comprising a cell-surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, wherein the proteinaceous molecule 3 comprises the first binding site for binding to the first epitope on the cell-surface molecule of (a), the sixth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent, wherein the first binding site of the proteinaceous molecule 1 and the first binding site of the proteinaceous molecule 3 are the same, and wherein the first cell-surface molecule and the first epitope on the first cell
  • the effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based.
  • the effector moiety is not the saponin derivative or the saponin conjugate of the invention.
  • An aspect of the invention relates to a third pharmaceutical combination, comprising: (a) the fourth pharmaceutical composition of the invention and (b) the sixth pharmaceutical composition of the invention, wherein the first cell-surface molecule is expressed on a tumor cell surface, and preferably the first cell-surface molecule is a tumor cell-specific surface molecule, and wherein preferably the first epitope is a first tumor-cell specific epitope.
  • the second pharmaceutical combination or third pharmaceutical combination comprises or consists of an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, single-domain antibody (sdAb), scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a ligand for a cell-surface molecule such as a receptor such as EGF and a cytokine, a single-domain antibody (sdAb), preferably VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin,
  • An aspect of the invention relates to a seventh pharmaceutical composition
  • a seventh pharmaceutical composition comprising: (a) the saponin conjugate of the invention; and (b) the conjugate comprising proteinaceous molecule 2 and an effector moiety of the invention, or the conjugate comprising proteinaceous molecule 3 and an effector moiety of the invention, and optionally further comprising a pharmaceutically acceptable excipient and/or diluent.
  • the effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based.
  • the effector moiety is not the saponin derivative or the saponin conjugate of the invention.
  • An aspect of the invention relates to the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, for use as a medicament.
  • An aspect of the invention relates to the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, for use in the treatment or prevention of a cancer or of an autoimmune disease such as rheumatoid arthritis.
  • a preferred embodiment is the first pharmaceutical combination of the invention, or the second pharmaceutical combination of the invention, or third pharmaceutical composition of the invention, for use according to the invention, preferably in a human patient, wherein the first cell surface molecule and the third cell surface molecule are CD71 and/or the second cell surface molecule is CD71, and/or the first proteinaceous molecule and the third proteinaceous molecule are a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the second proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the effector moiety is an oligonucleotide, preferably, the first, second and third cell surface molecule is
  • An embodiment is the saponin derivative of the invention, or the saponin conjugate of the invention, wherein the saponin on which the saponin derivative is based or on which the saponin conjugate is based, is isolated from a plant.
  • the saponin is isolated from a part of a plant, such as the root, or from a part of a tree, such as the bark.
  • the saponin is isolated from roots derived from a plant.
  • the term “saponin“ has its regular scientific meaning and here refers to a group of amphipatic glycosides which comprise one or more hydrophilic glycone moieties combined with a lipophilic aglycone core which is a sapogenin.
  • the saponin may be naturally-occurring or synthetic (i.e., non- naturally occurring).
  • the term “saponin” includes naturally-occurring saponins, derivatives of naturally-occurring saponins as well as saponins synthesized de novo through chemical and/or biotechnological synthesis routes.
  • the term “cell-surface molecule” has its regular scientific meaning and here refers to a molecule that is present and exposed at the outside surface of a cell such as a blood cell or an organ cell, such as a mammalian cell, such as a human cell.
  • the term “saponin derivative” has its regular scientific meaning and here refers to a saponin, i.e.
  • the saponin derivative is provided by chemical modification of an aldehyde group, in a saponin upon which the saponin derivative is based, i.e. the saponin is provided and an aldehyde group is chemically modified therewith providing the saponin derivative.
  • the saponin that is derivatised for provision of the saponin derivative is a naturally occurring saponin.
  • the saponin derivative is a synthetic saponin, typically the saponin derivative is a derivatisation of a natural saponin, and is thus derived from a natural saponin, although a saponin derivative can also be derived from a synthetic saponin which may or may not have a natural counterpart.
  • the saponin derivative has not a natural counterpart, i.e. the saponin derivative is not produced naturally by e.g. plants or trees.
  • the saponin derivative further has one or more chemical modifications at positions where previously any of a carboxyl group, an acetate group and/or an acetyl group was present in the non-derivatised or derivatised saponin before being subjected to chemical modification for provision of the saponin derivative.
  • the saponin derivative is provided by chemical modification of any one or more of a carboxyl group, an acetate group and/or an acetyl group in a saponin upon which the saponin derivative is based, i.e. the saponin is provided and an aldehyde group, a carboxyl group, an acetate group and/or an acetyl group is chemically modified therewith providing the saponin derivative.
  • the term “mono-desmosidic saponin” has its regular scientific meaning and here refers to a triterpenoid saponin containing a single saccharide chain bound to the aglycone core, wherein the saccharide chain consists of one or more saccharide moieties.
  • the term “bi-desmosidic saponin” has its regular scientific meaning and here refers to a triterpenoid saponin containing two saccharide chains bound to the aglycone core, wherein each of the two saccharide chains consists of one or more saccharide moieties.
  • triterpenoid saponin has its regular scientific meaning and here refers to a saponin having a triterpenoid-type of aglycone core structure.
  • the triterpenoid saponin differs from a saponin based on a steroid glycoside such as sapogenol in that such saponin comprising steroid glycoside has a steroid core structure, and the triterpenoid saponin differs from a saponin based on an alkaloid glycoside such as tomatidine in that such saponin comprising alkaloid glycoside has an alkaloid core structure.
  • conjugates has its regular scientific meaning and here refers to at least a first molecule that is covalently bound through chemical bonds to at least a second molecule, therewith forming a covalently coupled assembly comprising or consisting of the first molecule and the second molecule.
  • Typical conjugates are an ADC, an AOC, and SO1861-EMCH (EMCH linked to the aldehyde group of the aglycone core structure of the saponin).
  • tumor cell-specific surface molecule and the term “tumor cell-specific receptor” have their regular scientific meaning and here refer to a molecule or a receptor that is expressed and exposed at the surface of a tumor cell and not at the surface of a healthy, non-cancerous cell, or is expressed at the surface of a healthy, non-cancerous cell to a lower extent than the level of expression (number of molecules/receptors) at the surface of the tumor cell.
  • nucleic acid As used herein, the terms “nucleic acid”, “oligonucleotide” and “polynucleotide” are synonymous to one another and are to be construed as encompassing any polymeric molecule made of units, wherein a unit comprises a nucleobase (or simply “base” e.g., being a canonical nucleobase like adenine (A), cytosine (C), guanine (G), thymine (T), or uracil (U), or any known non-canonical, modified, or synthetic nucleobase like 5-methylcytosine, 5-hydroxymethylcytosine, xanthine, hypoxanthine, 7-methylguanine; 5,6-dihydrouracil etc.) or a functional equivalent thereof, which renders said polymeric molecule capable of engaging in hydrogen bond-based nucleobase pairing (such as Watson–Crick base pairing) under appropriate hybridisation conditions with naturally-occurring nucleic acids such as deoxyrib
  • nucleic acid under the present definition can be construed as encompassing polymeric molecules that chemically are DNA or RNA, as well as polymeric molecules that are nucleic acid analogues, also known as xeno nucleic acids (XNA) or artificial nucleic acids, which are polymeric molecules wherein one or more (or all) of the units are modified nucleotides or are functional equivalents of nucleotides.
  • Nucleic acid analogues are well known in the art and due to various properties, such as improved specificity and/or affinity, higher binding strength to their target and/or increased stability in vivo, they are extensively used in research and medicine.
  • nucleic acid analogues include but are not limited to locked nucleic acid (LNA) (that is also known as bridged nucleic acid (BNA)), phosphorodiamidate morpholino oligomer (PMO also known as Morpholino), peptide nucleic acid (PNA), glycol nucleic acid (GNA), threose nucleic acid (TNA), hexitol nucleic acid (HNA), 2’-deoxy-2’-fluoroarabinonucleic acid (FANA or FNA), 2’-deoxy-2’-fluororibonucleic acid (2’-F RNA or FRNA); altritol nucleic acids (ANA), cyclohexene nucleic acids (CeNA) etc.
  • LNA locked nucleic acid
  • BNA bridged nucleic acid
  • PMO phosphorodiamidate morpholino oligomer
  • PNA phosphorodiamidate morpholino oligomer
  • PNA
  • length of a nucleic acid is expressed herein the number of units from which a single strand of a nucleic acid is build. Because each unit corresponds to exactly one nucleobase capable of engaging in one base pairing event, the length is frequently expressed in so called “base pairs" or "bp" regardless whether the nucleic acid in question is a single stranded (ss) or double stranded (ds) nucleic acid.
  • base pairs or “bp”
  • nucleic acid in question is a single stranded (ss) or double stranded (ds) nucleic acid.
  • 1 bp corresponds to 1 nucleotide, abbreviated to 1 nt.
  • a single stranded nucleic acid made of 1000 nucleotides is described as having a length of 1000 base pairs or 1000 bp, which length can also be expressed as 1000 nt or as 1 kilobase that is abbreviated to 1 kb.2 kilobases or 2 kb are equal to the length of 2000 base pair which equates 2000 nucleotides of a single stranded RNA or DNA.
  • nucleic acids as defined herein may comprise or consist of units not only chemically being nucleotides but also being functional equivalents thereof, the length of nucleic acids will preferentially be expressed herein in “bp” or "kb” rather than in the equally common in the art denotation "nt”.
  • the nucleic acid as disclosed herein is no longer than 1 kb, preferably no longer than 500 bp, most preferably no longer than 250 bp.
  • nucleic acid is an oligonucleotide (or simply an oligo) defined as nucleic acid no longer than 100 bp, i.e.
  • oligonucleotides in accordance with the above provided definition, being any polymeric molecule made of no more than 100 units, wherein each unit comprises a nucleobase or a functional equivalent thereof, which renders said oligonucleotide capable of engaging in hydrogen bond-based nucleobase pairing under appropriate hybridisation conditions with DNA or RNA.
  • each unit comprises a nucleobase or a functional equivalent thereof, which renders said oligonucleotide capable of engaging in hydrogen bond-based nucleobase pairing under appropriate hybridisation conditions with DNA or RNA.
  • oligonucleotide will be construed as possibly comprising or consisting of RNA, DNA, or a nucleic acid analogue such as but not limited to LNA (BNA), PMO (Morpholino), PNA, GNA, TNA, HNA, FANA, FRNA, ANA, CeNA and/or the like.
  • RNAi-mediated gene-targeting has its regular scientific meaning and here refers to the in vivo, ex vivo or in vitro approach of influencing functioning of the gene in a cell by transferring into said cell an oligonucleotide, such as a small double-stranded RNA molecule, that targets mRNA involved in transcription of the gene: for example, small double-stranded RNA molecules are capable of efficiently triggering RNAi silencing of specific genes.
  • bridged nucleic acid in short, or “locked nucleic acid” or “LNA” in short or 2'-O,4'-C-aminoethylene or 2'-O,4'-C-aminomethylene bridged nucleic acid (BNA NC ), has its regular scientific meaning and here refers to a modified RNA nucleotide.
  • a BNA is also referred to as ‘constrained RNA molecule’ or ‘inaccessible RNA molecule’.
  • a BNA monomer can contain a five- membered, six-membered or even a seven-membered bridged structure with a “fixed” C3’-endo sugar puckering.
  • the bridge is synthetically incorporated at the 2’, 4’-position of the ribose to afford a 2’, 4’-BNA monomer.
  • a BNA monomer can be incorporated into an oligonucleotide polymeric structure using standard phosphoramidite chemistry known in the art.
  • a BNA is a structurally rigid oligonucleotide with increased binding affinity and stability.
  • BNA also refers to BNA NC or 2',4'-BNA NC (2'-O,4'-aminoethylene bridged nucleic acid) and here refers to an oligonucleotide that contains one or more nucleotide building blocks with a six-member bridged structure with an N-O linkage, and with an (N-H) or (N-Me) residue.
  • payload has its regular scientific meaning and here refers to a biologically active molecule, such as for example a cytotoxic (anti-cancer) drug molecule.
  • proteinaceous has its regular scientific meaning and here refers to a molecule comprising at least two amino acid residues linked via a peptide bond with each other so that the molecule relates to, resembles, or is a polypeptide or a protein, meaning that the molecule possesses, to some degree, the physicochemical properties characteristic of a protein, is of protein, relating to protein, containing protein, pertaining to protein, consisting of protein, resembling protein, or being a protein.
  • proteinaceous refers to the presence of at least two amino acid residues linked via a peptide bond with each other so that at least a part of the molecule that resembles or is a protein, wherein ‘protein’ is to be understood to include a chain of amino-acid residues at least two residues long, thus including a peptide, a polypeptide and a protein and an assembly of proteins or protein domains.
  • the at least two amino-acid residues are for example linked via (an) amide bond(s), such as (a) peptide bond(s).
  • the amino-acid residues are natural amino-acid residues and/or artificial amino-acid residues such as modified natural amino- acid residues. It is preferred that a proteinaceous molecule is a molecule comprising at least two amino-acid residues, preferably between 2 and about 2.000 amino-acid residues. Also preferred is a proteinaceous molecule that is a molecule comprising from 2 to 20 (typical for a peptide) amino acids.
  • a proteinaceous molecule that is a molecule comprising from 21 to 1.000 amino acid residues (typical for a polypeptide, a protein, a protein domain, such as an antibody, a Fab, an scFv, a ligand for a receptor such as EGF).
  • the amino-acid residues are (typically) linked via (a) peptide bond(s).
  • said amino-acid residues are or comprise (modified) (non-)natural amino acid residues.
  • binding molecule has its regular scientific meaning and here refers to a molecule capable of specifically binding to another molecule such as a cell-surface molecule, e.g. a cell- surface receptor.
  • Typical binding molecules are peptides, proteins, non-protein molecules, cell- surface receptor ligands, protein ligands, that can bind to e.g. a protein, a lipid, a (poly)saccharide, such as a cell-surface receptor or a cell-surface molecule.
  • Specifically binding here refers to specific and selective binding with higher affinity than non-specific background binding.
  • the term “moiety” has its regular scientific meaning and here refers to a molecule that is bound, linked, conjugated to a further molecule, linker, assembly of molecules, etc., and therewith forming part of a larger molecule, conjugate, assembly of molecules.
  • a moiety is an molecule that is covalently bound to another molecules, involving one or more chemical groups initially present on the effector molecule.
  • saporin is a typical effector molecule.
  • the saporin is a typical effector moiety in the ADC.
  • an AON such as a BNA or an siRNA is a typical effector moiety in the AOC.
  • the term “aglycone core structure” has its regular scientific meaning and here refers to the aglycone core of a saponin without the one or two carbohydrate antenna or saccharide chains (glycans) bound thereto.
  • quillaic acid is the aglycone core structure for SO1861, QS- 7 and QS-21.
  • the glycans of a saponin are mono-saccharides or oligo-saccharides, such as linear or branched glycans.
  • QS-21 also referred to as “QS21”
  • QS21 refers to any one of the isomers of QS-21.
  • a typical natural extract comprising QS-21 will comprise a mixture of the different isomers of QS-21.
  • a single isomer can be isolated.
  • Saponinum album has its normal meaning and here refers to a mixture of saponins produced by Merck KGaA (Darmstadt, Germany) containing saponins from Gypsophila paniculata and Gypsophila arostii, containing SA1657 and mainly SA1641.
  • Quillaja saponin has its normal meaning and here refers to the saponin fraction of Quillaja saponaria and thus the source for all other QS saponins, mainly containing QS-18 and QS-21.
  • QS-21 or “QS21” has its regular scientific meaning and here refers to a mixture of QS-21 A-apio ( ⁇ 63%), QS-21 A-xylo ( ⁇ 32%), QS-21 B-apio ( ⁇ 3.3%), and QS-21 B-xylo ( ⁇ 1.7%).
  • QS-21A has its regular scientific meaning and here refers to a mixture of QS-21 A-apio ( ⁇ 65%) and QS-21 A-xylo ( ⁇ 35%).
  • QS-21B has its regular scientific meaning and here refers to a mixture of QS-21 B-apio ( ⁇ 65%) and QS-21 B-xylo ( ⁇ 35%).
  • Quil-A refers to a commercially available semi-purified extract from Quillaja saponaria and contains variable quantities of more than 50 distinct saponins, many of which incorporate the triterpene-trisaccharide substructure Gal-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)]-GlcA- at the C-3beta- OH group found in QS-7, QS-17, QS18, and QS-21.
  • the saponins found in Quil-A are listed in van Setten (1995), Table 2 [Dirk C. van Setten, Gerrit van de Maschinenen, Gijsbert Zomer and Gideon F. A.
  • Quil-A and Quillaja saponin are fractions of saponins from Quillaja saponaria and both contain a large variety of different saponins with largely overlapping content. The two fractions differ in their specific composition as the two fractions are gained by different purification procedures.
  • QS1861 and the term “QS1862” refer to QS-7 and QS-7 api.
  • QS1861 has a molecular mass of 1861 Dalton
  • QS1862 has a molecular mass of 1862 Dalton.
  • QS1862 is described in Fleck et al. (2019) in Table 1, row no.28 [Juliane Deise Fleck, Andresa Heemann Betti, Francini Pereira da Silva, Eduardo Artur Troian, Chris Olivaro, Fernando Ferreira and Simone Gasparin Verza, Saponins from Quillaja saponaria and Quillaja brasiliensis: Particular Chemical Characteristics and Biological Activities, Molecules 2019, 24, 171; doi:10.3390/molecules24010171].
  • the described structure is the api-variant QS1862 of QS-7.
  • the molecular mass is 1862 Dalton as this mass is the formal mass including a proton at the glucuronic acid. At neutral pH, the molecule is deprotonated. When measuring in mass spectrometry in negative ion mode, the measured mass is 1861 Dalton.
  • saccharide chain has its regular scientific meaning and here refers to any of a glycan, a carbohydrate antenna, a single saccharide moiety (monosaccharide) or a chain comprising multiple saccharide moieties (oligosaccharide, polysaccharide).
  • the saccharide chain can consist of only saccharide moieties or may also comprise further moieties such as any one of 4E-Methoxycinnamic acid, 4Z-Methoxycinnamic acid, and 5-O-[5-O-Ara/Api-3,5-dihydroxy-6- methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), such as for example present in QS-21.
  • the terms “SO1861” and “SO1862” refer to the same saponin of Saponaria officinalis, though in deprotonated form or api form, respectively.
  • the molecular mass is 1862 Dalton as this mass is the formal mass including a proton at the glucuronic acid. At neutral pH, the molecule is deprotonated. When measuring the mass using mass spectrometry in negative ion mode, the measured mass is 1861 Dalton.
  • the terms “SO1831” and “SO1832” refer to the same saponin of Saponaria officinalis, though in deprotonated form or api form, respectively.
  • the molecular mass is 1832 Dalton as this mass is the formal mass including a proton at the glucuronic acid. At neutral pH, the molecule is deprotonated. When measuring the mass using mass spectrometry in negative ion mode, the measured mass is 1831 Dalton.
  • Api/Xyl-“ or “Api- or Xyl-“ in the context of the name of a saccharide chain has its regular scientific meaning and here refers to the saccharide chain either comprising an apiose (Api) moiety, or comprising a xylose (Xyl) moiety.
  • transformation has its regular scientific meaning and here refers to the chemical transformation or modification of a first functional group or first chemical group or first chemical moiety such that a second functional group or second chemical group or second chemical moiety is provided.
  • An example is the transformation of an aldehyde group carbonyl group into a semicarbazone functional group through reaction with a semicarbazide.
  • antibody as used herein is used in the broadest sense, which may refer to an immunoglobulin (Ig) defined as a protein belonging to the class IgG, IgM, IgE, IgA, or IgD (or any subclass thereof), or a functional binding fragment or binding domain of an immunoglobulin.
  • Ig immunoglobulin
  • a "binding fragment” or a “binding domain” of an immunoglobulin or of an antibody is defined as antigen-binding fragment or -domain or other derivative of a parental immunoglobulin that essentially maintains the antigen binding activity of such parental immunoglobulin.
  • Functional fragments and functional domains are antibodies in the sense of the present invention even if their affinity to the antigen is lower than that of the parental immunoglobulin.
  • "Functional fragments and -domains" in accordance with the invention include, but are not limited to, F(ab')2 fragments, Fab' fragments, Fab fragments, scFv, dsFv, single-domain antibody (sdAb), monovalent IgG, scFv-Fc, reduced IgG (rIgG), minibody, diabodies, triabodies, tetrabodies, Fc fusion proteins, nanobodies, variable V domains such as VHH, Vh, and other types of antigen recognizing immunoglobulin fragments and domains.
  • the fragments and domains may be engineered to minimize or completely remove the intermolecular disulphide interactions that occur between the CH1 and CL domains.
  • Functional fragment and –domains offer the advantage of greater tumor penetration because of their smaller size.
  • the functional fragment or – domain can be more evenly distributed throughout the tumor mass as compared to whole immunoglobulin.
  • antibody-drug conjugate has its regular scientific meaning and here refers to any conjugate of an antibody such as an IgG, an immunoglobulin, an immunoglobulin binding fragment, a binding derivative or binding fragment or binding domain of an antibody such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single- domain antibody (sdAb), preferably a VHH, a ligand for a cell-surface molecule such as a receptor such as EGF and a cytokine, multiple VH domains, single-domain antibodies, VHH, or camelid VH, etc., and any molecule that can exert a therapeutic effect when contacted with cells of a subject such as a human patient, such as an active pharmaceutical ingredient, and any molecule that can exert a therapeutic
  • antibody-oligonucleotide conjugate has its regular scientific meaning and here refers to any conjugate of an antibody such as an IgG, an immunoglobulin, an immunoglobulin binding fragment, a binding derivative or binding fragment or binding domain of an antibody such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, a ligand for a cell-surface molecule such as a receptor such as EGF and a cytokine, multiple VH domains, single-domain antibodies, VHH, or camelid VH, etc., and any oligonucleotide molecule that can exert a therapeutic effect when contacted with cells of a subject such as
  • linker has its regular scientific meaning, and linkers are commonly known in the art of bioconjugation. Common linkers are for example described in G.T. Hermanson (Bioconjugation Techniques, Third edition, Elsevier, 2013, ISBN: 978-0-12-382239-0).
  • linker refers to a chemical moiety or a linear stretch of amino-acid residues complexed through peptide bonds, which is suitable for covalently attaching (binding) a first molecule, such as a saponin, to another molecule, e.g. to a (proteinaceous) ligand or to an effector molecule or to a scaffold, for example composed of or comprising amino-acid residues, nucleic acids, etc.
  • the linker comprises a chain of atoms linked by chemical bonds. Any linker molecule or linker technology known in the art can be used in the present disclosure. Where indicated, the linker is a linker for covalently binding of molecules through a chemical group on such a molecule suitable for forming a covalent linkage or bond with the linker.
  • the linker may be a non-cleavable linker, e.g., the linker is stable in physiological conditions.
  • the linker may be a cleavable linker, e.g.
  • a linker that is cleavable, in the presence of an enzyme or at a particular pH range or value, or under physiological conditions such as intracellular conditions in the endosomes such as the late endosomes and the lysosomes of mammalian cells such as human cells.
  • effector molecule when referring to the effector molecule as part of e.g. a covalent conjugate, has its regular scientific meaning and here refers to a molecule or moiety that has an effect on any one or more of a target molecule and/or proximally to any one or more of a target molecule and/or that can selectively bind to any one or more of a target molecule, wherein the target molecules are for example: a protein, a peptide, a carbohydrate, a saccharide such as a glycan, a (phospho)lipid, a nucleic acid such as DNA, RNA, an enzyme, and regulates the biological activity of such one or more target molecule(s).
  • target molecules are for example: a protein, a peptide, a carbohydrate, a saccharide such as a glycan, a (phospho)lipid, a nucleic acid such as DNA, RNA, an enzyme, and regulates the biological activity of such one or more target molecule(
  • the effector molecule is for example a molecule selected from any one or more of a small molecule such as a drug molecule, a toxin such as a protein toxin, an oligonucleotide such as an AON such as a BNA, a xeno nucleic acid or an siRNA, an enzyme, a peptide, a protein, or any combination thereof.
  • a small molecule such as a drug molecule
  • a toxin such as a protein toxin
  • an oligonucleotide such as an AON such as a BNA
  • a xeno nucleic acid or an siRNA an enzyme, a peptide, a protein, or any combination thereof.
  • an effector molecule or an effector moiety is a molecule or moiety selected from any one or more of a small molecule such as a drug molecule, a toxin such as a protein toxin, an oligonucleotide such as an AON such as a BNA, a xeno nucleic acid or an siRNA, an enzyme, a peptide, a protein, or any combination thereof, that can selectively bind to any one or more of the target molecules: a protein, a peptide, a carbohydrate, a saccharide such as a glycan, a (phospho)lipid, a nucleic acid such as DNA, RNA, an enzyme, and that upon binding to the target molecule regulates the biological activity of such one or more target molecule(s).
  • a small molecule such as a drug molecule
  • a toxin such as a protein toxin
  • an oligonucleotide such as an AON such as a BNA
  • An effect can include, but is not limited to, biological effect, a therapeutic effect, an imaging effect, and/or a cytotoxic effect.
  • an effector molecule or moiety can exert a biological effect inside a cell such as a mammalian cell such as a human cell, such as in the cytosol of said cell.
  • an effect can include, but is not limited to, promotion or inhibition of the target's activity, labelling of the target, and/or cell death.
  • effector molecules and effector moieties are thus protein toxins, drug molecules, plasmid DNA, toxins such as toxins comprised by antibody-drug conjugates (ADCs), oligonucleotides such as an AON such as an siRNA, BNA, nucleic acids comprised by an antibody- oligonucleotide conjugate (AOC), enzymes.
  • ADCs antibody-drug conjugates
  • oligonucleotides such as an AON such as an siRNA, BNA
  • enzymes for example, an effector molecule or moiety is a molecule which can act as a ligand that can increase or decrease (intracellular) enzyme activity, gene expression, or cell signalling.
  • the effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based.
  • the effector moiety is not the saponin derivative or the saponin conjugate of the invention.
  • HSP27 relates to a BNA oligonucleotide molecule which silences the expression of HSP27 in the cells.
  • ApoB or “ApoBBNA”, or “ApoB#02” relates to a BNA oligonucleotide molecule which silences the expression of apoB in the cells.
  • the terms first, second, third and the like in the description and in the claims, are used for distinguishing between for example similar elements, compositions, constituents in a composition, or separate method steps, and not necessarily for describing a sequential or chronological order.
  • L as used such as in a saponin derivative or an antibody-saponin conjugate or construct comprising a linker, represents ‘labile linker’ which is cleaved under slightly acid conditions (pH ⁇ 6.6, such as pH 4.0 – 5.5) in the endosome, endolysosome and in the lysosome of mammalian cells, such as human cells, such as a human tumor cell.
  • GalNAc has its regular scientific meaning and here refers to N- acetylgalactosamine and to the IUPAC name thereof: 2-(acetylamino)-2-deoxy-D-galactose.
  • (GalNAc)3Tris has its regular scientific meaning in for example the field of siRNA- based therapy, and here refers to a moiety comprising three GalNAc units each separately covalently bound to the hydroxyl groups of tris(hydroxymethyl)aminomethane (Tris) (IUPAC name: 2-amino-2-(hydroxymethyl) propane-1,3-diol), preferably via at least one linker.
  • (GalNAc)3Tris can exist as a free amine comprising molecule or may be further functionalized via the remaining amine binding site, for example to form the (GalNAc)3Tris-moiety comprising conjugates described herein.
  • the embodiments of the invention described herein can operate in combination and cooperation, unless specified otherwise.
  • the various embodiments, although referred to as “preferred” or “e.g.” or “for example” or “in particular” and the like are to be construed as exemplary manners in which the invention may be implemented rather than as limiting the scope of the invention.
  • a composition comprising components A and B should not be limited to a composition consisting only of components A and B, rather with respect to the present invention, the only enumerated components of the composition are A and B, and further the claim should be interpreted as including equivalents of those components.
  • DAR has its regular scientific meaning of Drug/Antibody Ratio and refers to the average drug to antibody ratio for a given preparation of antibody drug conjugate (ADC) and here refers to a ratio of the amount of bound SO1861 moieties, or SPT001, or bound payload, e.g. an AON such as ApoB BNA with respect to the conjugate molecule.
  • indefinite article “a” or “an” does not exclude the possibility that more than one of the element or component are present, unless the context clearly requires that there is one and only one of the elements or components.
  • the indefinite article “a” or “an” thus usually means “at least one”.
  • Figure 1 SO1861-SC-Mal synthesis
  • Figure 2A-B SO1861-semicarbazone (‘SO1861-SC’) synthesis
  • Figure 2A SO1861-SC-Mal (blocked) synthesis
  • Figure 3 SO1861-EMCH synthesis
  • Figure 4A-C Dendron4-amine synthesis.
  • FIG. 7A-B Structure of hCD71mab-dendron(EMCH-SO1861)4 conjugate.
  • Figure 10A-B Cell killing assay (MTS) of SO1861-SC-Mal + 5 pM EGF-dianthin on HeLa ( Figure 10 A) and A431 (Figure 10 B) cell lines. Note: the legend to Figure 10A and Figure 10B is the same and is displayed next to the graphs in Figure 10A.
  • Figure 11A-B Cell killing assay (MTS) of SO1861-SC-Mal + 10 pM Cetuximab-saporin on HeLa ( Figure 11 A) and A431 ( Figure 11 B) cell lines. Note: the legend to Figure 11A and Figure 11B is the same and is displayed next to the graphs in Figure 11A.
  • Figure 12A-B Cell killing assay (MTS) of SO1861-SC-Mal + 50 pM Trastuzumab-saporin on HeLa ( Figure 12 A) and A431 ( Figure 12 B) cell lines. Note: the legend to Figure 12A and Figure 12B is the same and is displayed next to the graphs in Figure 12A.
  • Figure 13A-B HSP27 gene silencing of SO1861-SC-Mal + Tmab-HSP27BNA on A431 cell lines. ( Figure 13 A) Relative HSP27 expression in the absence of saponin.
  • FIG. 13 B Relative HSP27 expression under influence of saponin analogues SO1861-EMCH and SO1861-SC-Mal and of wild type (non-modified, non-derivatised) saponin SO1861.
  • Figure 14A-B Cell killing assay (MTS) of SO1861-SC-Mal, SO1861-SC, SO1861-EMCH and non- derivatised SO1861 on HeLa ( Figure 14 A) and A431 ( Figure 14B) cell lines.
  • MTS Cell killing assay
  • Figure 15 Hemolytic activity of modified SO1861 (SO1861 derivatives) and non-derivatised SO1861 on human red blood cells (RBC).
  • Figure 16A-B EGFR/CD71 targeted cell killing in A431 cells ( Figure 16A) and CaSKi cells ( Figure 16B).
  • Cetuximab-(SC-SO1861)4 also called Cetuximab-SC-SO1861 (DAR 4) and Cetuximab- (EMCH-SO1861)4 titration + fixed concentration 10 pM CD71mab-saporin and controls on A431 cells (EGFR++/CD71+) and CaSKi cells (EGFR++/CD71+).
  • Figure 16A and Figure 16B are the same and is displayed next to the graphs in Figure 16B.
  • Figure 17A-B EGFR/CD71 targeted cell killing in HeLa cells (Figure 17A) and A2058 cells ( Figure 17B).
  • Figure 18 HER2/CD71 targeted cell killing.
  • Figure 19 A Trastuzumab-(SC- SO1861)4 or Trastuzumab-(Cys-EMCH-SO1861)4 titration + fixed concentration 10 pM CD71mab- saporin and controls on JIMT-1 cells (HER2+/-/CD71+) ( Figure 19 A), and MDA-MB-468 (HER2- /CD71+) ( Figure 19 B).
  • Figure 19A the legend to Figure 19A and Figure 19B is the same and is displayed next to the graphs in Figure 19B.
  • Figure 20 EGFR/HER2 targeted gene silencing in A431 cells.
  • the term ‘S’ as used such as in an antibody- oligonucleotide conjugate represents ‘stable linker’, which is a non-cleavable linker in the endosome, endolysosome and in the lysosome of mammalian cells, such as human cells, such as a human tumor cell, thus under slightly acidic conditions (pH ⁇ 6.6, such as pH 4.0 – 5.5).
  • FIG 21 Cell killing assay (MTS) of various cell lines treated with 5 pM EGFdianthin (Dia-EGF), 10 pM Cetuximab-saporin (Cet-SPRN), 50 pM Trastuzumab-saporin (Tras-SPRN) or 10 pM CD71- saporin (CD71-SPRN).
  • Figure 22 HSP27 mRNA expression levels in A431 cells. Displayed is the relative HSP27 expression in A431 cells contacted with Cetuximab-(SC-SO1861)-HSP27 (DAR4/DAR2) and Cetuximab-(EMCH-SO1861)-HSP27 (DAR4/DAR2).
  • the conjugates comprise two BNA molecules (DAR 2) and four SO1861 moieties (DAR 4).
  • Figure 23A-F CD71/EGFR targeted cell killing in SK-BR3 (Figure 23A), JIMT-1 (Figure 23B), HeLa ( Figure 23C), and MDA-MB-468 cells (Figure 23D) A431 (Figure 23E) and A2058 ( Figure 23F).
  • Figure 25 Relative apoB expression analysis in liver tissue of C57BL/6J mice.
  • Figure 26 Serum apoB protein analysis C57BL/6J mice. NB, levels for 0.1 mg/kg ApoB#02 (196 hrs), 0.01 mg/kg (GalNAc)3-ApoB + 5 mg/kg (GalNAc)3-SO1861 (196 hrs and 336 hrs) and 0.1 mg/kg (GalNAc)3-ApoB + 5 mg/kg (GalNAc)3-SO1861 (196 hrs) are not reported.
  • Figure 27 Serum LDL-cholesterol (LDL-C) analysis in C57BL/6J mice.
  • Figure 28 Serum ALT analysis in C57BL/6J mice.
  • Figure 29 ApoB expression analysis and cell viability assay on primary human hepatocytes for ApoB#02 conjugates.
  • Figure 30 Relative apoB expression analysis in liver tissue of C57BL/6J mice.
  • Figure 31 Serum apoB protein analysis in C57BL/6J mice.
  • Figure 32 Serum LDL-cholesterol (LDL-C) analysis in C57BL/6J mice.
  • Figure 33 Serum ALT analysis in C57BL/6J mice.
  • Figure 34A-C synthesis of trivalent GalNAc.
  • Figure 35A-D synthesis of trivalent GalNAc .
  • Figure 36A-D Trifunctional linker-(L-hydrazone-SO1861)-(L-BNA oligo)-(Trivalent-GalNAc) synthesis.
  • Figure 37A-E Trifunctional linker-(dendron(-L-hydrazone-SO1861)4)-(L-BNA oligo)-(Trivalent- GalNAc) synthesis. Note that the drawing of Figure 37 E encompasses two sheets, labelled Fig.37 E and Fig.37 E (continued), which two sheets together display the conjugation of molecule 21 with molecule 19, therewith forming conjugate molecule 22.
  • Figure 38A-C Trifunctional linker-(dendron(-L-hydrazone-SO1861)8)-(BNA oligo)-(Trivalent- GalNAc) synthesis.
  • Figure 38 B encompasses two sheets, labelled Fig.38 B and Fig.38 B (continued), which two sheets together display the conjugation of molecule 24 with molecule 18, therewith forming conjugate molecule 25 (intermediate 12).
  • Figure 38 C encompasses two sheets, labelled Fig. 38 C and Fig. 38 C (continued), which two sheets together display the conjugation of molecule 25 with molecule 21, therewith forming conjugate molecule 26.
  • Figure 39A-C Trifunctional linker-(L-semicarbazone-SO1861)- (BNA oligo) – (Trivalent-GalNAc) synthesis.
  • Figure 40A-F Trifunctional linker – (dendron(L-semicarbazone-SO1861)4) - (L-BNA oligo) - (Trivalent-GalNAc) synthesis.
  • Figure 40 E encompasses two sheets, labelled Fig.40 E and Fig.40 E (continued), which two sheets together display the conjugation of molecule 40 with molecule 20, therewith forming conjugate intermediate 24.
  • Figure 41A-D Trifunctional linker – (dendron(L-semicarbazone-SO1861)8) - (L-BNA oligo) - (Trivalent-GalNAc) synthesis.
  • Figure 41 A encompasses two sheets, labelled Fig.41 A and Fig.41 A (continued), which two sheets together display the conjugation of molecule 43 with molecule 37, therewith forming conjugate (molecule 44) intermediate 25.
  • Figure 41 B encompasses two sheets, labelled Fig. 41 B and Fig. 41 B (continued), which two sheets together display the conjugation of molecule 44 with molecule 18, therewith forming conjugate molecule 45 (intermediate 26).
  • Figure 41 C encompasses two sheets, labelled Fig.41 C and Fig.41 C (continued), which two sheets together display the conjugation of molecule 45 with molecule 20, therewith forming conjugate molecule 46 (intermediate 27).
  • FIG 42 Trifunctional linker-(L-SPT001)-(blocked TCO)-(trivalent GalNAc synthesis
  • Figure 43A-B Trifunctional linker-(blocked DBCO)-(L-BNA oligo)-(trivalent GalNAc) synthesis
  • Figure 44 Overview of conjugates obtainable by applying TFL methodology.
  • Figure 44 encompasses two sheets, labelled Fig.44 and Fig.44 (continued), which two sheets together display the conjugation of Trifunctional linker labelled molecule 4 with Targeting ligand labelled molecule 41, Effector labelled molecule 12, and one of the Enhancers labelled molecule 3, 19, 25, 28, 40 and 45 or one of the Blocking agents for controls labelled molecule 5, 12a and 50, therewith forming a conjugate with the general conjugate structure as depicted in the box, comprising group R1 and group R2, wherein R1 is any one of the groups depicted next to the boxed conjugate and R2 is any one of the groups depicted next to the boxed conjugate.
  • Figure 45 Graphic of antibody(-L-SC-SO1861)4 – (S-HSP27 BNA)2.
  • the amino-acid residues labelled ‘Cys’ and ‘Lys’ are part of the amino-acid sequence of the antibody. DETAILED DESCRIPTION
  • the present invention will be described with respect to particular embodiments, but the invention is not limited thereto but only by the claims.
  • the saponin derivative of the invention has at least one, preferably to, more preferably all three of: (i) a reduced toxicity when cell viability is considered of cells contacted with the saponin derivatives; (ii) enhanced activity when potentiation of e.g.
  • toxin cytotoxicity or AON-mediated gene silencing such as BNA-mediated gene silencing is considered (without wishing to be bound by any theory: relating to similar or improved endosomal escape enhancing activity of the modified saponin), if the aldehyde functional group is transformed to a semicarbazone functional group according to formula (I); and/or (iii) reduced hemolytic activity, when compared with the toxicity, activity and haemolytic activity of unmodified saponin on which the saponin derivative is based.
  • the inventors provide saponin derivatives with an improved therapeutic window, since for the saponin derivatives the cytotoxicity is lower than cytotoxicity determined for their naturally occurring counterparts, the haemolytic activity is lower than haemolytic activity determined for the naturally occurring counterparts of the saponin derivatives, the ratio between IC50 values for cell toxicity and e.g. IC50 values for toxin potentiation or IC50 values for gene silencing is similar or increased, and/or since the ratio between IC50 values for saponin haemolytic activity and e.g. IC50 values for toxin potentiation or IC50 values for gene silencing is similar or increased.
  • a ligand such as an antibody or such as one or more GalNAc moieties such as three GalNAc moieties
  • a cell-surface molecule such as a receptor such as CD71 (when the ligand is a CD71 binding antibody in the saponin conjugate) or such as ASGPR, preferably ASGPR1 (when the ligand is one or more GalNAc moieties, preferably three GalNAc moieties), together with an AOC such as an antibody – BNA conjugate, despite the medium to low expression of the cell-surface receptor targeted by the cell-surface molecule binding-molecule (e.g.
  • the saponin derivative and, preferably, also the saponin conjugate of the invention comprise the semicarbazone functional group.
  • the inventors now provide for a more potent saponin derivative and a more potent saponin conjugate, when the activation or potentiating of an effector moiety such as an effector moiety comprised by an ADC or AOC, is considered, relating to the presence of the semicarbazone functional group with which the saponin is linked to the cell-surface molecule (such as a cell-surface receptor) binding molecule, for example an antibody or at least one sdAb capable of binding to said cell-surface molecule.
  • an effector moiety such as an effector moiety comprised by an ADC or AOC
  • This has the benefit that a lower amount of the saponin derivatives according to the invention should be administered to a patient in need of potentiation of e.g.
  • the hydrazone functional group is at the basis for the improved activity of the saponin conjugate of the invention comprising a saponin derivative of the invention, such as a conjugate comprising the saponin, an oligonucleotide and a cell-surface receptor ligand such as one to three GalNAc moieties (for targeting (liver) cells expressing ASGPR), wherein the activity is the potentiation of the effector moiety activity such as a gene-silencing oligonucleotide, inside the cytosol or nucleus of the targeted cell by endosomal escape enhancement.
  • a saponin derivative of the invention such as a conjugate comprising the saponin, an oligonucleotide and a cell-surface receptor ligand such as one to three GalNAc moieties (for targeting (liver) cells expressing ASGPR)
  • the activity is the potentiation of the effector moiety activity such as a gene-silencing oligonucleotide, inside
  • the saponin derivatives can be formed from such naturally occurring saponins, such as SO1861, equally active SO1832 and QS-21 (isoforms), preferably from SO1861 or SO1832.
  • saponin derivatives according to the invention are equally suitable, when saponins with decreased cytotoxicity are to be provided.
  • the saponin SO1832 consists of the quillaic acid aglycone core with the carbohydrate substituent Gal-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)]-GlcA- at the C-3beta-OH group and with the carbohydrate substituent Xyl-(1 ⁇ 3)-Xyl-(1 ⁇ 4)-Rha-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)-4-OAc-Qui-(1 ⁇ 4)]-Fuc- at the C-28-OH group (See also Table A1).
  • the chemical formula is C82H128O45 and the exact mass is 1832,77 Dalton.
  • the saponin structure of SO1832 is according to molecule (SO1832):
  • the modifications lead to an increased critical micelle concentration (CMC) when compared with the corresponding unmodified saponin.
  • CMC critical micelle concentration
  • the saponin derivative according to formula (VIII) (or Molecule (VIII)) has an increased CMC when compared to their corresponding underivatised saponin and are hence explicitly envisaged embodiments of the invention.
  • an increased CMC is advantageous for several reasons.
  • an increased CMC may facilitate the use of the modified saponins (saponin derivatives) in subsequent conjugation reactions since free molecules are generally more susceptible to conjugation reactions than molecules ordered in a micellar structure.
  • an increased CMC when compared to unmodified saponin is advantageous since the free saponin molecules will be more readily available to interact with their biological target than in case these saponin derivatives are ordered in a micellar structure.
  • An increased CMC may also be useful to facilitate the large-scale production and concentration of the saponin derivatives since at concentrations beyond (above) the critical micellar concentration, saponins form micelles which hinder isolation (e.g. using preparative HPLC).
  • the observed increased CMC was not associated with increased cytotoxicity or haemolytic activity.
  • the relationship between CMC and cytotoxicity is not predictable and complex, as can for example be seen from the data in Table 2 of de Groot et al.
  • the increased CMC is also associated with an increased ratio: IC50 hemolysis / IC50 activity, compared to the corresponding free saponin, such that this saponin derivative is a particularly preferred embodiment of the invention.
  • the inventors thus provide saponin derivatives with an improved therapeutic window when cytotoxicity is considered and/or when haemolytic activity is considered, and when the potentiation of e.g. toxins is considered and/or when an increased CMC compared to the corresponding underivatised saponin is considered.
  • Such saponin derivatives of the invention are in particular suitable for application in a therapeutic regimen involving e.g. an ADC or an AOC for the prophylaxis or treatment of e.g.
  • a cancer or a GalNAc-oligonucleotide conjugate for the prophylaxis or treatment of e.g. a cancer, hypercholesterolemia, cardiovascular disease or enhanced level of LDL- cholesterol above normal levels for healthy subjects in a (human) subject in need thereof.
  • the safety of such saponin derivatives is improved when cytotoxicity and/or haemolytic activity is considered, especially when such saponin derivatives are administered to a patient in need of e.g. treatment with an ADC or with and AOC or with a conjugate comprising at least one GalNAc moiety and comprising an oligonucleotide, e.g. an AON such as a BNA for silencing a gene such as HSP27 and apoB.
  • an AON such as a BNA for silencing a gene such as HSP27 and apoB.
  • An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is a monodesmosidic triterpene glycoside or a bidesmosidic triterpene glycoside, more preferably a bidesmosidic triterpene glycoside.
  • a series of saponins known in the art have shown to enhance endosomal escape of molecules, which are most often bidesmosidic triterpene glycosides, although also a series of monodesmosidic triterpene glycosides have shown such enhancing activity.
  • Table A1 summarizes the series of saponins for which endosomal escape enhancing activity has been established. Such saponins are good starting points for synthesising the saponin derivatives of the invention.
  • SO1861 has proven to be a suitable natural saponin for derivatisation according to the invention.
  • SO1832 has similar activity when compared to SO1861, as has been established by the inventors, also SO1832 is a suitable natural saponin for derivatisation according to the invention.
  • QS-21 can be a suitable natural saponin for derivatisation according to the invention, although the inventors established that the cytotoxicity and haemolytic activity of QS-21 is relatively higher than cytotoxicity and haemolytic activity of e.g., SO1861.
  • An embodiment is the saponin derivative according to the invention, wherein the saponin derivative comprises an aglycone core structure selected from the group consisting of: 2alpha-hydroxy oleanolic acid; 16alpha-hydroxy oleanolic acid; hederagenin (23-hydroxy oleanolic acid); 16alpha,23-dihydroxy oleanolic acid; gypsogenin; quillaic acid; protoaescigenin-21(2-methylbut-2-enoate)-22-acetate; 23-oxo-barringtogenol C-21,22-bis(2-methylbut-2-enoate); 23-oxo-barringtogenol C-21(2-methylbut-2-enoate)-16,22-diacetate; digitogenin; 3,16,28-trihydroxy oleanan-12-en; gypsogenic acid, and derivatives thereof, preferably the saponin derivative comprises an aglycone core structure selected from quillaic acid and
  • a sufficiently high dose of derivatised saponin can be applied in e.g. tumor therapy for a cancer patient in need thereof, while the (risk for) cytotoxic side-effects and the (risk for) undesired haemolytic activity exerted or induced by the saponin derivative is decreased when compared with the application of the natural saponin counterpart (i.e. the non-derivatised saponin).
  • Improvements of the therapeutic window of the saponin derivatives of the invention are for example apparent for the exemplified saponin derivatives in Table 3 and Table 4: the ratio between the IC50 for either cytotoxicity, or haemolytic activity and the IC50 for endosomal escape enhancing activity are listed, as well as the haemolytic activity, cytotoxicity and the activity, and the CMC.
  • An embodiment is the saponin derivative according to the invention, wherein the saponin derivative comprises an aglycone core structure selected from the group consisting of quillaic acid, gypsogenin, and derivatives thereof, preferably the saponin derivative comprises an aglycone core structure selected from the group consisting of quillaic acid and derivatives thereof, wherein the first saccharide chain R 1 , when present, is linked to the C3 atom (also denoted as ‘C-3’ atom) or the C28 atom (also denoted as ‘C-28’ atom) of the aglycone core structure, preferably to the C3 atom, and/or wherein the second saccharide chain R 2 , when present, is linked to the C28 atom of the aglycone core structure.
  • the saponin derivative comprises an aglycone core structure selected from the group consisting of quillaic acid, gypsogenin, and derivatives thereof, preferably the saponin derivative comprises
  • An embodiment is the saponin derivative according to the invention, wherein the saponin on which the saponin derivative is based is a penta-cyclic triterpene saponin of the 12,13- dehydrooleanane type, preferably the saponin is a monodesmosidic or bidesmosidic penta-cyclic triterpene saponin of the 12,13-dehydrooleanane type.
  • An embodiment is the saponin derivative according to the invention, wherein the saponin on which the saponin derivative is based is a mono-desmosidic or bi-desmosidic triterpene saponin belonging to the type of a 12,13-dehydrooleanane with the aldehyde group in position C-23 and optionally comprising a glucuronic acid group in a carbohydrate substituent at the C-3beta-OH group of the saponin, preferably a bi-desmosidic triterpene saponin belonging to the type of a 12,13- dehydrooleanane with the aldehyde group in position C-23 and comprising a glucuronic acid group in a carbohydrate substituent at the C-3beta-OH group of the saponin.
  • a preferred embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to formula (IV):
  • R 1 is selected from H, GlcA-, Glc-, Gal-, Rha-(1 ⁇ 2)-Ara-, Gal-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)]-GlcA-, Glc-(1 ⁇ 2)-[Glc-(1 ⁇ 4)]-GlcA-, Glc-(1 ⁇ 2)-Ara-(1 ⁇ 3)-[Gal-(1 ⁇ 2)]-GlcA-, Xyl-(1 ⁇ 2)-Ara-(1 ⁇ 3)-[Gal-(1 ⁇ 2)]-GlcA-, Glc-(1 ⁇ 3)-Gal-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)]-Glc-(1 ⁇ 4)-Gal-, Rha-(1 ⁇ 2)-Gal-(1 ⁇ 3)-[Glc-(1 ⁇ 2)]-GlcA-, Ara-(1 ⁇ 4)-Rha-(1
  • R 1 is Gal-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)]-GlcA-; and R 2 is selected from: Glc-(1 ⁇ 3)-Xyl-(1 ⁇ 4)-Rha-(1 ⁇ 2)-[Xyl-(1 ⁇ 3)-4-OAc-Qui-(1 ⁇ 4)]-Fuc-, Xyl-(1 ⁇ 3)-Xyl-(1 ⁇ 4)-Rha-(1 ⁇ 2)-[3,4-di-OAc-Qui-(1 ⁇ 4)]-Fuc-, Api-(1 ⁇ 3)-Xyl-(1 ⁇ 4)-Rha-(1 ⁇ 2)-[R 12 -( ⁇ 4)]-Fuc- wherein R 12 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, Xyl-(1
  • Saponin derivatives comprising such a R 1 group and such an R 2 group are preferably saponin derivatives based on a saponin listed in Table A1, for which endosomal escape enhancing activity has been established and/or predicted based on structural similarity or analogy.
  • An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is a derivative of a saponin selected from the group of saponins consisting of: Quillaja bark saponin, dipsacoside B, saikosaponin A, saikosaponin D, macranthoidin A, esculentoside A, phytolaccagenin, aescinate, AS6.2, NP-005236, AMA-1, AMR, alpha-Hederin, NP-012672, NP- 017777, NP-017778, NP-017774, NP-018110, NP-017772, NP-018109, NP-017888, NP-017889, NP-018108, SA1641, AE X55, NP-017674, NP-017810, AG1, NP-003881, NP-017676, NP- 017677, NP-017706, NP-017705, NP-017773, NP-017775, SA1657,
  • saponins are essentially saponins displaying endosomal escape enhancing activity as established by the inventors, or that are structurally highly similar to saponins for which the endosomal escape enhancing activity has been established. Structural outline of these saponins is summarized in Table A1. Since SO1861 and SO1832 are about equally active (when endosomal escape enhancing effects are assessed), application of SO1861 and SO1832 in the saponin derivatives and in the saponin conjugates of the invention is equally preferred.
  • the saponin derivative is a derivative of a saponin selected from the group of saponins consisting of: Quillaja bark saponin, dipsacoside B, saikosaponin A, saikosaponin D, macranthoidin A, esculentoside A, phytolaccagenin, aescinate, AS6.2, NP-005236, AMA-1, AMR, alpha-Hederin, NP-012672, NP- 017777, NP-017778, NP-017774, NP-018110, NP-017772, NP-018109, NP-017888, NP-017889, NP-018108, SA1641, AE X55, NP-017674, NP-017810, AG1, NP-003881, NP-017676, NP- 017677, NP-017706, NP-017705, NP-017773, NP-017775, SA1657, AG
  • a derivative based on SO1861 and SO1832 is equally preferred.
  • An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is selected from the group consisting of derivatives of: SO1861, SA1657, GE1741, SA1641, QS-21, QS-21A, QS-21 A-api, QS-21 A-xyl, QS-21B, QS-21 B-api, QS-21 B-xyl, QS-7- xyl, QS-7-api, QS-17-api, QS-17-xyl, QS1861, QS1862, Quillajasaponin, Saponinum album, QS- 18, Quil-A, Gyp1, gypsoside A, AG1, AG2, SO1542, SO1584, SO1658, SO1674, SO1832, SO1862, SO1904, stereoisomers thereof and combinations thereof, preferably the saponin derivative is selected from the group consisting of a SO1861 derivative, a GE1741 derivative, a SA1641
  • An embodiment is the saponin derivative of the invention, wherein the saponin on which the saponin derivative is based is any one or more of: a) saponin selected from any one or more of list A: - Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; - Gypsophila elegans saponin mixture, or a saponin isolated from Gypsophila elegans; - Saponinum album saponin mixture, or a saponin isolated from Saponinum album; - Saponaria officinalis saponin mixture, or a saponin isolated from Saponaria officinalis; and - Quillaja bark saponin mixture, or a saponin isolated from Quillaja bark, for example Quil- A, QS-17-api,
  • An embodiment is the saponin derivative of the invention, wherein the saponin (on which the saponin derivative is based) is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS-7, SA1641, a saponin isolated from Saponaria officinalis, Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; preferably wherein the saponin is any one or more of QS- 21, SO1832, SO1861, SA1641 and GE1741; more preferably wherein the saponin is QS-21, SO1832 or SO1861; most preferably being SO1861.
  • the saponin is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS-7, SA1641, a sap
  • An embodiment is the saponin derivative of the invention, wherein the saponin (on which the saponin derivative is based) is a saponin isolated from Saponaria officinalis, preferably wherein the saponin is any one or more of Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; more preferably wherein the saponin is any one or more of SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; even more preferably wherein the saponin is any one or more of SO1832, SO1861 and SO1862; even more preferably wherein the saponin is SO1832 and SO1861; most preferably being SO1861.
  • the saponin is any one or more of Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO18
  • saponin derivative of the invention wherein the saponin derivative is according to formula (V) (See Figure 2A, Molecule (V); see the detailed outline in the Examples section, here below), formula (VI), formula (VII) (See Figure 1 and Figure 2B, Molecule (VII); see the detailed outline in the Examples section, here below) or formula (VIII) (See Figure 2B, Molecule (VIII); see the detailed outline in the Examples section, here below):
  • the saponin derivatives according to Molecule (V), Molecule (VII) and/or Molecule (VIII) are preferred, the saponin derivatives according to Molecule (V) and Molecule (VIII) are more preferred. See Figure 1 and 2 and the Examples section, here below. Even more preferred is the saponin derivative according to formula (VIII) or Molecule (VIII).
  • a saponin derivative of the invention wherein the saponin derivative is according to molecule (AA): , wherein represents a saponin moiety according to formula (SM): , wherein R 1 and R 2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23.
  • AA molecule
  • SM saponin moiety according to formula (SM):
  • R 1 and R 2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide
  • the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23.
  • the saponin moiety is for example based on any one of the saponins listed in the embodiments outlined here above and/or in Table A1, and SO1861, SO1832 and QS-21 are preferred, although SO1861 and SO1832 are most preferred.
  • Preferred is a saponin derivative of the invention, wherein the saponin derivative is according to molecule (BB):
  • molecule (BB) is the covalent conjugation product obtained by the covalent conjugation of the saponin derivative according to molecule (AA) outlined here above with the tri-functional linker according to formula (XXI): (XXI).
  • SM saponin moiety according to formula (SM): , wherein R 1 and R 2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide according to the invention and as outlined here above, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23 according to the invention. Suitable saponins are for example outlined inTable A1. SO1861, SO1832 and QS-21 are preferred, although SO1861 and SO1832 are more preferred. A preferred embodiment is the saponin derivative according to the invention, characterized in that the saponin derivative comprises a single saponin moiety.
  • a preferred embodiment is the saponin derivative according to the invention, characterized in that the saponin derivative comprises more than one saponin moiety, such as 2-64 moieties, preferably 4-32 moieties, more preferably 4- 16 moieties, most preferably 4-8 moieties such as 4 or 8 moieties.
  • Saponin derivatives comprising more than a single saponin moiety, such as a saponin derivative based on a G2 dendron or G3 dendron, comprising four or eight saponin moieties respectively, which are provided with the semicarbazone functional group, provide the advantage of providing higher extent of endosomal escape enhancing activity by a single saponin derivative molecule as compared to a saponin derivative comprising a single saponin moiety.
  • Part of the invention is the saponin derivative according to molecule (JJ): which molecule (JJ) is the conjugate product of conjugation of N,N'-((9S,19S)-14-(6- aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo-4,11,14,17- tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide first with the saponin derivative according to molecule (KK), as displayed here above, and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido- 3,6,9,12-tetraoxapentadecan-15-oate. Also part of the invention is the saponin derivative according to molecule (QQ):
  • molecule (QQ) is the conjugate product of conjugation of (2S)-N-[(1S)-1- ⁇ [2-(6-amino-N- ⁇ 2- [(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl ⁇ hexanamido)ethyl]carbamoyl ⁇ -5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate first with the saponin derivative according to the invention and according to molecule (KK) as displayed and described here above, and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido- 3,6,9,12-tetraoxapentadecan-15-oate.
  • An embodiment is the saponin derivative according to the invention, characterized in that the saponin derivative has a molecular weight of less than 2500 g/mol, preferably less than 2300 g/mol, more preferably less than 2150 g/mol.
  • An embodiment is the saponin derivative according to the invention, characterized in that the saponin derivatisation has a molecular weight of less than 400 g/mol, preferably less than 300 g/mol, more preferably less than 270 g/mol.
  • the molecular weight of the saponin derivatisation corresponds to the molecular weight of the saponin derivative exclusive of the aglycone core and the one (for monodesmosidic saponins) or two (for bidesmosidic saponins) glycon (sugar) chains.
  • Pharmaceutical compositions and combinations comprising a saponin derivative An aspect of the invention relates to a first pharmaceutical composition comprising the saponin derivative according to the invention and optionally a pharmaceutically acceptable excipient and/or diluent.
  • An embodiment is the first pharmaceutical composition according to the invention comprising the saponin derivative according to the invention, preferably a pharmaceutically acceptable diluent, and further comprising: ⁇ a pharmaceutically acceptable salt, preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganese, potassium, sodium, strontium, or zinc salt, preferably NaCl; and/or ⁇ a pharmaceutically acceptable buffer system, such as a phosphate, a borate, a citrate, a carbonate, a histidine, a lactate, a tromethamine, a gluconate, an aspartate, a glutamate, a tartarate, a succinate, a malate, a fumarate, an acetate and/or a ketoglutarate containing buffer system.
  • a pharmaceutically acceptable salt preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganese, potassium, sodium
  • An embodiment is the first pharmaceutical composition according to the invention comprising the saponin derivative according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and has a pH within the range of 2-11, preferably within the range of 4-9, more preferably within the range of 6-8.
  • An embodiment is the first pharmaceutical composition according to the invention comprising a saponin derivative according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and wherein the concentration of the saponin derivative is within the range of 10 -12 to 1 mol/l, preferably within the range of 10 -9 to 0.1 mol/l, more preferably within the range of 10 -6 to 0.1 mol/l.
  • a first pharmaceutical composition is suitable for use in combination with e.g. an ADC or an AOC.
  • the first pharmaceutical composition is administered to a patient in need of administration of the ADC or AOC, before the ADC or AOC is administered, together with the ADC or AOC, or (shortly) after administration of the ADC or the AOC to the patient in need of such ADC or AOC therapy.
  • the first pharmaceutical composition is mixed with a pharmaceutical composition comprising the ADC or the AOC, and a suitable dose of the mixture obtained is administered to a patient in need of ADC or AOC therapy.
  • the saponin derivative comprised by the first pharmaceutical composition enhances the efficacy and potency of the effector molecule comprised by such an ADC or AOC, when the saponin derivative and the ADC or AOC co-localize inside a target cell such as a tumor cell.
  • the effector molecule is released into the cytosol of the target cell to a higher extent, compared to contacting the same cells with the same dose of ADC or AOC in the absence of the saponin derivative.
  • An embodiment is the first pharmaceutical composition of the invention, wherein the saponin derivative is the saponin derivative according to formula (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) (depicted in Figure 2), the saponin derivative according to formula (VIII) or any combination thereof.
  • An aspect of the invention relates to a first pharmaceutical combination comprising: (a) the first pharmaceutical composition of the invention; and (b) a second pharmaceutical composition comprising a conjugate of a cell-surface molecule binding-molecule and an effector moiety, wherein the cell-surface molecule binding-molecule is a proteinaceous molecule such as an antibody, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • An aspect of the invention relates to a first pharmaceutical combination comprising: (a) the first pharmaceutical composition of the invention; and (b) a second pharmaceutical composition comprising any one or more of: a conjugate of a cell- surface molecule binding-molecule and an effector moiety, an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody- oligonucleotide conjugate and a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • Such a receptor ligand can be a receptor ligand known in the art of cell-targeting therapy, such as EGF.
  • a receptor ligand targets a receptor on a diseased cell such as a tumor cell or an autoreactive immune cell (autoimmune cell) such as in rheumatoid arthritis.
  • a receptor ligand is a proteinaceous molecule such as a peptide or a protein, although non-proteinaceous receptor ligands known in the art are equally suitable.
  • Such receptor ligands can also be selected from molecules such as adnectins, anticalins, affibodies, etc., etc.
  • the common denominator for the receptor ligands is their specificity for an epitope on a target cell, for targeted delivery of an effector moiety bound to the receptor ligand, reminiscent to the targeted delivery of effector moieties such as toxins, enzymes, oligonucleotides, drug molecules, etc., linked to e.g. an antibody or a single domain antibody, etc.
  • Suitable cell-surface molecule binding- molecules are proteinaceous molecules such as antibodies, sdAb, etc., and non-proteinaceous molecules, suitable for targeting a selected cell (type) and therewith suitable for bringing a saponin derivative of the invention and/or a payload, effector molecule, effector moiety such as a drug, toxin, oligonucleotide, enzyme, in close proximity of the target cell surface to which the cell-surface molecule binding-molecule can bind.
  • the cell-surface molecule is a receptor.
  • the binding of the cell-surface molecule binding-molecule to the target cell is followed by transfer of the saponin derivate and/or the payload, effector molecule, effector moiety, to the endosome of the cell to which the cell-surface molecule binding-molecule is bound.
  • An aspect of the invention relates to a therapeutic combination comprising: ⁇ the first pharmaceutical composition of the invention; and ⁇ a second pharmaceutical composition comprising any one or more of an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • An aspect of the invention relates to a third pharmaceutical composition
  • a third pharmaceutical composition comprising the saponin derivative of the invention and further comprising a conjugate of a cell-surface molecule binding-molecule and an effector moiety, wherein the cell-surface molecule binding-molecule is a proteinaceous molecule such as an antibody, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • An aspect of the invention relates to a third pharmaceutical composition
  • a conjugate of a cell- surface molecule binding-molecule and an effector moiety comprising any one or more of: a conjugate of a cell- surface molecule binding-molecule and an effector moiety, an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody- oligonucleotide conjugate and a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • An aspect of the invention relates to a third pharmaceutical composition
  • a third pharmaceutical composition comprising the saponin derivative of the invention and further comprising any one or more of: an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-nucleic acid conjugate or a receptor-ligand – nucleic acid conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • An embodiment is the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, wherein the second pharmaceutical composition or the third pharmaceutical composition comprises any one or more of an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, wherein the drug is for example a toxin such as saporin or dianthin, and wherein the oligonucleotide is for example an AON such as an siRNA or a BNA, for example for gene silencing of apolipoprotein B (apoB) or HSP27.
  • the drug is for example a toxin such as saporin or dianthin
  • the oligonucleotide is for example an AON such as an siRNA or a BNA, for example for gene silencing of apolipoprotein B (apoB) or HSP27.
  • An embodiment is the first pharmaceutical combination comprising the second pharmaceutical composition of the invention, or the third pharmaceutical composition of the invention, wherein the second pharmaceutical composition or the third pharmaceutical composition comprises any one or more of an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody- oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, wherein preferably the toxin is a protein toxin.
  • an embodiment is the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, wherein the saponin derivative is a saponin derivative selected from the group consisting of derivatives of: SO1861, SA1657, GE1741, SA1641, QS-21, QS-21A, QS-21 A-api, QS-21 A-xyl, QS-21B, QS-21 B-api, QS-21 B-xyl, QS-7-xyl, QS-7-api, QS- 17-api, QS-17-xyl, QS1861, QS1862, Quillajasaponin, Saponinum album, QS-18, Quil-A, Gyp1, gypsoside A, AG1, AG2, SO1542, SO1584, SO1658, SO1674, SO1832, SO1862, SO1904, stereoisomers thereof and combinations thereof, preferably the saponin derivative is selected from the group consisting of an SO1861 derivative, a GE1741 derivative, an SA1641 derivative, a QS- 21 derivative,
  • saponin derivate according to molecule (AA), molecule (BB), molecule (KK), molecule (JJ) and molecule (QQ). Even more preferred is the saponin derivative according to any one or more of formula (VII) or Molecule (VII), formula (V) or Molecule (V), and formula (VIII) or Molecule (VIII). Even more preferred is the saponin derivative according to formula (VIII) or Molecule (VIII).
  • An embodiment is the third pharmaceutical composition according to the invention comprising a saponin derivative according to the invention, and further comprising preferably a pharmaceutically acceptable diluent, and further comprising: ⁇ a pharmaceutically acceptable salt, preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganese, potassium, sodium, strontium, or zinc salt, preferably NaCl; and/or ⁇ a pharmaceutically acceptable buffer system, such as a phosphate, a borate, a citrate, a carbonate, a histidine, a lactate, a tromethamine, a gluconate, an aspartate, a glutamate, a tartarate, a succinate, a malate, a fumarate, an acetate and/or a ketoglutarate containing buffer system.
  • a pharmaceutically acceptable salt preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganes
  • An embodiment is the third pharmaceutical composition according to the invention comprising a saponin derivative according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and has a pH within the range of 2-11, preferably within the range of 4-9, more preferably within the range of 6-8.
  • An embodiment is the third pharmaceutical composition according to the invention comprising a saponin derivative according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and wherein the concentration of the saponin derivative is within the range of 10 -12 to 1 mol/l, preferably within the range of 10 -9 to 0.1 mol/l, more preferably within the range of 10 -6 to 0.1 mol/l.
  • the first pharmaceutical combination comprising the second pharmaceutical composition or the third pharmaceutical composition according to the invention, wherein the second pharmaceutical composition or the third pharmaceutical composition comprise an antibody-toxin conjugate, an antibody-drug conjugate, or an antibody-oligonucleotide conjugate, wherein the antibody is a cell-surface molecule targeting molecule which can bind to a tumor-cell surface molecule, preferably to a tumor-cell receptor such as a tumor-cell specific receptor, more preferably to a receptor selected from CD71, CD63, CA125, EpCAM(17-1A), CD52, CEA, CD44v6, FAP, EGF- IR, integrin, syndecan-1, vascular integrin alpha-V beta-3, HER2, EGFR, CD20, CD22, Folate receptor 1, CD146, CD56, CD19, CD138, CD27L receptor, PSMA, CanAg, integrin-alphaV, CA6, CD33, mesothelin, Cripto, CD3, CD30, CD239, CD70
  • Such an antibody can also be a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, a string of single-domain antibodies, a binding molecule comprising VHH, a binding molecule comprising VH, etc.
  • sdAb single-domain antibody
  • the first pharmaceutical combination comprising the second pharmaceutical composition or the third pharmaceutical composition according to the invention wherein the effector moiety is an oligonucleotide comprising or consisting of any one or more of a nucleic acid and a xeno nucleic acid, preferably selected from any one or more of a vector, a gene, a cell suicide inducing transgene, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), anti-sense oligonucleotide (ASO, AON), short interfering RNA (siRNA), microRNA (miRNA), DNA aptamer, RNA aptamer, mRNA, mini-circle DNA, peptide nucleic acid (PNA), phosphoramidate morpholino oligomer (PMO), locked nucleic acid (LNA), bridged nucleic acid (BNA), 2’-deoxy-2’-fluoroarabino nucleic acid (FANA), 2’-O-methoxyeth,
  • the first pharmaceutical combination comprising the second pharmaceutical composition or the third pharmaceutical composition according to the invention wherein the effector moiety comprises or consists of at least one proteinaceous molecule, preferably selected from any one or more of a peptide, a protein, an enzyme such as urease and Cre-recombinase, a ribosome-inactivating protein, a proteinaceous toxin selected from any one or more of a viral toxin such as apoptin; a bacterial toxin such as Shiga toxin, Shiga-like toxin, Pseudomonas aeruginosa exotoxin (PE) or exotoxin A of PE, full-length or truncated diphtheria toxin (DT), cholera toxin; a fungal toxin such as alpha-sarcin; a plant toxin including ribosome- inactivating proteins and the A chain of type 2 ribosome-inactivating proteins such as dian
  • dianthin-30 or dianthin-32 saporin e.g. saporin-S3 or saporin-S6, bouganin or de-immunized derivative debouganin of bouganin, shiga-like toxin A, pokeweed antiviral protein, ricin, ricin A chain, modeccin, modeccin A chain, abrin, abrin A chain, volkensin, volkensin A chain, viscumin, viscumin A chain; or an animal or human toxin such as frog RNase, or granzyme B or angiogenin from humans, or any fragment or derivative thereof; preferably the protein toxin is dianthin and/or saporin.
  • saporin e.g. saporin-S3 or saporin-S6, bouganin or de-immunized derivative debouganin of bouganin, shiga-like toxin A, pokeweed antiviral protein, ricin, ricin A chain, modeccin, modeccin A
  • An embodiment is the first pharmaceutical combination comprising the second pharmaceutical composition of the invention or the third pharmaceutical composition of the invention, wherein the second pharmaceutical composition or the third pharmaceutical composition comprises any one or more of an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody- oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, wherein the drug is for example a toxin such as saporin and dianthin, and wherein the oligonucleotide is for example an AON such as an siRNA or a BNA, for example for gene silencing of apolipoprotein B (apoB) or HSP27.
  • the drug is for example a toxin such as saporin and dianthin
  • the oligonucleotide is for example an AON such as an siRNA or a BNA, for example for gene silencing of
  • the first pharmaceutical combination comprising the first pharmaceutical composition of the invention, or the third pharmaceutical composition of the invention, wherein the saponin derivative is any one or more of the saponin derivatives according to the invention.
  • An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use as a medicament.
  • An aspect of the invention relates to the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use as a medicament.
  • An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination comprising the first pharmaceutical composition of the invention, or the third pharmaceutical composition of the invention, for use as a medicament.
  • the first pharmaceutical composition of the invention wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof; the first pharmaceutical combination of the invention wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof, or the third pharmaceutical composition of the invention wherein the saponin derivative comprises, preferably consists the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the
  • An aspect of the invention is the provision of the saponin derivative as described herein, preferably the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof, for use as a medicament.
  • An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cancer or an auto-immune disease.
  • An aspect of the invention relates to the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cancer or an auto-immune disease.
  • An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination of the invention, or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cancer or an auto-immune disease.
  • the first pharmaceutical composition of the invention wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof; the first pharmaceutical combination of the invention wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof; or the third pharmaceutical composition of the invention wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI),
  • An aspect of the invention relates to the first pharmaceutical combination, the second pharmaceutical combination, or the third pharmaceutical composition, for use according to the invention, preferably in a human patient, wherein the first cell surface molecule and the third cell surface molecule are CD71 and/or the second cell surface molecule is CD71, and/or the first proteinaceous molecule comprised by the saponin conjugate and the third proteinaceous molecule are a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the second proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the effector moiety is an oligonucleotide, preferably, the first, second and third cell surface molecule is CD71, the first, second and third proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and the effector moiety is an oligonucle
  • An aspect of the invention relates to an antibody-drug conjugate, antibody-oligonucleotide conjugate, ligand-drug conjugate or ligand-oligonucleotide conjugate, comprising the saponin conjugate of the invention and an effector moiety according to the invention, preferably an antibody- oligonucleotide conjugate comprising the saponin conjugate of the invention and an effector moiety according to the invention.
  • An aspect of the invention relates to the antibody-drug conjugate, antibody-oligonucleotide conjugate, ligand-drug conjugate or ligand-oligonucleotide conjugate of the invention, preferably the antibody-oligonucleotide conjugate of the invention, for use as a medicament.
  • An aspect of the invention relates to the antibody-drug conjugate, antibody-oligonucleotide conjugate, ligand-drug conjugate or ligand-oligonucleotide conjugate of the invention, preferably the antibody-oligonucleotide conjugate of the invention, for use in the treatment or prevention of a disease or health problem related to presence of the diseased cell according to the invention, for use in the treatment or prevention of a disease or health problem related to the presence of the aberrant cell according to the invention, for use in the treatment or prevention of a cancer, for use in the treatment or prevention of an autoimmune disease such as rheumatoid arthritis, preferably in a human patient, wherein preferably, the first, second and third cell surface molecule is CD71, the first, second and third proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and the effector moiety is an oligonucleotide.
  • An aspect of the invention relates to an in vitro or ex vivo method for transferring a molecule from outside a cell to inside said cell, preferably into the cytosol of said cell, comprising the steps of: a) providing a cell; b) providing the molecule for transferring from outside the cell into the cell provided in step a); c) providing a saponin derivative according to the invention; d) contacting the cell of step a) in vitro or ex vivo with the molecule of step b) and the saponin derivative of step c), therewith establishing the transfer of the molecule from outside the cell into said cell.
  • an embodiment is the method of the invention, wherein the cell is a human cell such as a T- cell, an NK-cell, a tumor cell, and/or wherein the molecule of step b) is any one of: an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-oligonucleotide conjugate or a receptor- ligand – oligonucleotide conjugate, wherein the drug is for example a toxin and wherein the oligonucleotide is for example an AON such as an siRNA or a BNA, and/or wherein the saponin derivative is selected from the group consisting of derivatives of: SO1861, SA1657, GE1741, SA1641, QS-21, QS-21A, QS-21 A-api, QS-21 A-xyl, QS-21B, QS-21 B-api, QS-21 B-xyl, QS-7- xyl, QS-7-api, QS-17-api, QS
  • the in vitro or ex vivo method for transferring a molecule from outside a cell to inside said cell, preferably into the cytosol of said cell as described herein wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof.
  • a saponin conjugate of the invention comprising at least one saponin moiety, a cell surface-receptor targeting ligand (cell-targeting ligand) such as an antibody or a binding fragment or domain thereof, or one or more GalNAc moieties, and optionally an effector moiety such as an oligonucleotide, is applied in the method of the invention.
  • the conjugate without an effector moiety is applied together with an effector moiety or a further conjugate of an effector moiety and a cell surface-receptor targeting ligand (cell-targeting ligand) such as an antibody or a binding fragment or domain thereof, or one or more GalNAc moieties.
  • the conjugate comprising saponin and an effector moiety, in addition to a cell surface-receptor targeting ligand (cell-targeting ligand) such as an antibody or a binding fragment or domain thereof, or one or more GalNAc moieties, is also applied in the method (such a conjugate is also referred to as a 1-component conjugate).
  • a conjugate is also referred to as a 1-component conjugate.
  • An embodiment is the method of the invention, wherein the saponin conjugate is selected from any one of the saponin conjugates of the invention, including the 1-component conjugate.
  • the cell-targeting ligand is an antibody such as a monoclonal antibody or at least an sdAb, capable of binding to CD71. It is preferred that the cell with which the method is applied (over)expresses CD71.
  • the molecule selected for transferring into the selected cell by applying the method is an oligonucleotide according to the invention.
  • the saponin on which the saponin derivative comprised by the saponin conjugate is based is selected from SO1861, SO1832 and QS-21, preferably SO1861 and SO1832, more preferably SO1861.
  • Saponin conjugate based on the saponin derivatives An aspect of the invention relates to a saponin conjugate comprising a cell-surface molecule binding-molecule (also referred to as: cell surface-receptor targeting ligand and cell-targeting ligand) such as a first proteinaceous molecule (‘proteinaceous molecule 1’) that is covalently bound to the saponin derivative according to the invention, i.e. covalently linked to the saponin derivative.
  • the cell-surface molecule binding-molecule is covalently bound to the derivatisation in the saponin derivative, i.e. the derivatised aldehyde functional group of the saponin on which the saponin derivative is based, i.e.
  • the cell-surface molecule binding-molecule typically is a protein, such as an antibody or a binding fragment thereof, or a single-domain antibody (sdAb) or a binding molecule comprising a sdAb.
  • An embodiment is the saponin derivative according to the invention, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (IX) wherein n and m each are an integer independently selected from 1, 2, or 3; o is an integer selected from 0-10, preferably 2-7, more preferably 4-6.
  • An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to molecule (KK): , wherein represents a saponin moiety according to formula (SM):
  • R 1 and R 2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide according to the invention, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23 according to the invention. Examples of such saponins are depicted in Table A1.
  • An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to formula (VII) (or Molecule (VII): (VII).
  • An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to molecule (AA):
  • SM saponin moiety according to formula (SM): , wherein R 1 and R 2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide according to the invention, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23 according to the invention.
  • Preferred saponins are for example tabulated in Table A1.
  • An embodiment is the saponin conjugate of the invention, wherein the saponin comprised by the conjugate is any one or more of: a) saponin selected from any one or more of list A: - Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; - Gypsophila elegans saponin mixture, or a saponin isolated from Gypsophila elegans; - Saponinum album saponin mixture, or a saponin isolated from Saponinum album; - Saponaria officinalis saponin mixture, or a saponin isolated from Saponaria officinalis; and - Quillaja bark saponin mixture, or a saponin isolated from Quillaja bark, for example Quil- A, QS-17-api, QS-17
  • An embodiment is the saponin conjugate of the invention, wherein the saponin is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS- 7, SA1641, a saponin isolated from Saponaria officinalis, Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; preferably wherein the saponin is any one or more of QS-21, SO1832, SO1861, SA1641 and GE1741; more preferably wherein the saponin is QS-21, SO1832 or SO1861; most preferably being SO1861.
  • the saponin is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS- 7, SA1641, a saponin isolated from Saponaria officinalis
  • An embodiment is the saponin conjugate of the invention, wherein the saponin is a saponin isolated from Saponaria officinalis, preferably wherein the saponin is any one or more of Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; more preferably wherein the saponin is any one or more of SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; even more preferably wherein the saponin is any one or more of SO1832, SO1861 and SO1862; even more preferably wherein the saponin is SO1832 and SO1861; most preferably being SO1861.
  • An embodiment is the saponin derivative of the invention and/or the saponin conjugate of the invention based on the saponin derivative of the invention, wherein the at least one saponin is covalently bound to a tri-functional linker.
  • a preferred saponin derivative of the invention and/or a saponin conjugate of the invention is a derivative or a conjugate, wherein the at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties, is/are covalently bound via a trifunctional linker.
  • An example of a trifunctional linker that is suitable for incorporation into a saponin derivative or saponin conjugate of the invention is the trifunctional linker represented by formula (XXI):
  • An embodiment is the saponin conjugate of the invention and/or the saponin derivative of the invention, wherein a trifunctional linker, such as the trifunctional linker represented by formula (XXI), is covalently bound to one or more saponin moieties via a first arm of the linker, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties, and, when the saponin conjugate is considered, optionally and preferably also covalently bound to at least one GalNAc moiety, preferably 1-4 GalNAc moieties, more preferably 3 GalNAc moieties, via a second arm of the linker, and, when the saponin conjugate is considered, optionally and preferably also covalently bound to an effector moiety, preferably an oligonucleotide, preferably an AON such as a BNA or an siRNA, via a third arm of the trifunctional linker.
  • a trifunctional linker such as the trifunctional
  • the saponin conjugate of the invention wherein the at least one GalNAc moiety, preferably three GalNAc moieties, the at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties and preferably 1, 4 or 8 saponin moieties, and the oligonucleotide are covalently bound via a tri-functional linker, preferably with each of the GalNAc moiety or GalNAc moieties, the saponin or the saponin moieties and the oligonucleotide covalently bound to a separate arm of the tri-functional linker.
  • the at least one GalNAc moiety preferably three GalNAc moieties
  • the at least one saponin preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties and preferably 1, 4 or 8 saponin moieties
  • An embodiment is the saponin derivative of the invention or the saponin conjugate of the invention based on the saponin derivative, comprising one saponin moiety.
  • An embodiment is the saponin derivative of the invention, wherein the at least one saponin is covalently bound to a tri-functional linker.
  • a preferred saponin conjugate comprises at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties, covalently bound to a trifunctional linker.
  • An example of a trifunctional linker that is suitable for incorporation into a saponin conjugate of the invention is the trifunctional linker represented by formula (XXI).
  • An embodiment is the saponin conjugate of the invention, wherein the conjugate comprises at least one GalNAc moiety, at least one saponin and an oligonucleotide, which are covalently bound to each other via a tri-functional linker, preferably with each of the GalNAc moiety, the saponin and the oligonucleotide covalently bound to a separate arm of the tri-functional linker.
  • a preferred saponin conjugate of the invention based on the saponin derivative of the invention is a saponin conjugate, wherein the at least one GalNAc moiety, preferably three GalNAc moieties, at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties, and the oligonucleotide are covalently bound via a trifunctional linker, preferably with each of the GalNAc moiety or GalNAc moieties, the saponin or more than one saponin moieties and the oligonucleotide covalently bound to a separate arm of the trifunctional linker.
  • An example of a trifunctional linker that is suitable for incorporation into a saponin conjugate of the invention is the trifunctional linker represented by formula (XXI).
  • An embodiment is the saponin conjugate of the invention based on the saponin derivative of the invention, comprising at least one saponin covalently linked to a ligand for asialoglycoprotein receptor (ASGPR), wherein the ligand for ASGPR comprises at least one N-acetylgalactosamine (GalNAc) moiety, preferably three or four GalNAc moieties, more preferably three GalNAc moieties, more preferably the ligand for ASGPR comprises or consists of (GalNAc)3Tris, and further covalently linked to an oligonucleotide, wherein the at least one saponin is a monodesmosidic or bidesmosidic penta-cyclic triterpene saponin of the 12,13-dehydrooleanane type, preferably with an al
  • An embodiment is the oligonucleotide conjugate of the invention, wherein the at least one GalNAc moiety, preferably three GalNAc moieties, the at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties, and the oligonucleotide are covalently bound via a tri-functional linker, preferably with each of the GalNAc moiety or moieties, the saponin or saponin moieties and the oligonucleotide covalently bound to a separate arm of the tri-functional linker.
  • An embodiment is the oligonucleotide conjugate of the invention, comprising one saponin moiety, 4 saponin moieties or 8 saponin moieties.
  • An embodiment is the oligonucleotide conjugate of the invention, wherein the at least one saponin moiety is linked via a hydrazone bond or via a semicarbazone bond.
  • the at least one saponin is preferably covalently bound in the oligonucleotide conjugate via a semicarbazone bond.
  • Such a semicarbazone bond (with a linker) is for example formed involving the aldehyde group at the C-23 atom of the quillaic acid aglycone core structure of the saponin or of the gypsogenin aglycone core structure of the saponin (see Table A1 for examples of saponins of these types).
  • saponin conjugates of the invention are formed upon conjugation of e.g. one or more GalNAc moieties and/or an oligonucleotide, with a saponin derivative of the invention.
  • An aspect of the invention relates to a saponin conjugate based on a saponin derivative according to the invention, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (IX) wherein n and m each are an integer independently selected from 1, 2, or 3; o is an integer selected from 0-10, preferably 2-7, more preferably 4-6; and wherein the maleimide functional group is further transformed into a thioether bond through reaction with a first proteinaceous molecule (‘proteinaceous molecule 1’) comprising a thiol functional group according to formula (X)
  • the saponin derivatives, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (IX) wherein n and m each are an integer independently selected from 1, 2, or 3; and o is an integer selected from 0-10, preferably 2-7, more preferably 4-6; are suitable for application as a precursor for a conjugation reaction with a further molecule comprising
  • the maleimide functional group of the saponin derivative according to formula (IX) can form a thio-ether bond with such a free sulfhydryl group.
  • the saponin derivative according to formula (IX) can be covalently coupled to a peptide or a protein which comprises a free sulfhydryl group such as a cysteine with a free sulfhydryl group.
  • Such a protein is for example an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, for example camelid VH, or a ligand for a cell- surface molecule such as a receptor such as EGF and a cytokine.
  • sdAb single-domain antibody
  • VHH for example camelid VH
  • a ligand for a cell- surface molecule such as a receptor such as EGF and a cytokine.
  • an antibody that comprises a free sulfhydryl group provides a conjugate for targeted delivery of the saponin to and inside a cell, when the antibody (or the binding domain or fragment thereof) is an antibody for specific binding to a target cell surface molecule such as a receptor, e.g. as present on a tumor cell.
  • the saponin derivative is coupled to an antibody or VHH capable of binding to a tumor-cell specific surface molecule such as a receptor, e.g. HER2, EGFR, CD71, preferably CD71.
  • the saponin conjugate of the invention comprises (is based on) the saponin derivative according to the invention, all embodiments referring to the saponin derivative applies mutatis mutandis to the saponin conjugate. That is to say, the saponin conjugates of the invention are based on the saponin derivatives according to the invention, detailed here above.
  • a preferred embodiment is the saponin conjugate according to the invention, wherein the saponin conjugate is according to formula (XI) wherein R 1 and R 2 are as defined in any one of claims 1-10; n and m each are an integer independently selected from 1, 2 or 3; and o is an integer selected from 0-10, preferably 2-7, more preferably 4-6.
  • a highly preferred embodiment is the saponin conjugate according to to formula (XII) (XII).
  • An aspect of the invention relates to the saponin derivative of the invention, comprising one saponin moiety, and/or to the saponin conjugate of the invention, comprising one saponin moiety.
  • the at least one saponin (four saponin derivative moieties for the saponin conjugate according to formula (XII)a (see below), eight saponin derivative moieties for the saponin conjugate according to formula (XII)b) (see below) on which the saponin derivative comprised by the saponin conjugate is based, is any one or more of a saponin selected from list B or C, more preferably from list C.
  • the saponin is SO1861 or SO1832, more preferably SO1861.
  • Figure 7B displays a typical example of a saponin conjugate according to the formula (XII)a.
  • the Proteinaceous molecule 1 is here an antibody, preferably a human anti-CD71 antibody.
  • Four G2 dendrons each comprising four copies of a derivative of SO1861 comprising the semicarbazone functional group, are linked to Cysteine residues of the antibody, via a linker.
  • Figure 8B displays a typical example of a saponin conjugate according to the formula (XII)b.
  • the Proteinaceous molecule 1 is here an antibody, preferably a human anti-CD71 antibody.
  • the first proteinaceous molecule (the proteinaceous molecule 1) is a monoclonal antibody or a binding fragment or binding domain thereof, preferably an anti-CD71-antibody or at least one single domain antibody (sdAb) capable of binding to CD71, wherein the sdAb preferably is a VHH domain.
  • the proteinaceous molecule 1 is an antibody; preferably an anti-CD71 antibody or at least one sdAb capable of binding to CD71.
  • the saponin is SO1861 or SO1832.
  • the saponin derivative moieties comprised by the saponin conjugate are the same.
  • the saponin conjugate comprises preferably 1 or 2 conjugated copies of the dendron-(saponin)4-maleimide2, for which dendron-(saponin)4-maleimide2 as an example dendron-(SO1861)4-maleimide2 is displayed in Figure 4H. More preferred is a single conjugated copy of the dendron-(saponin)4-maleimide2 per antibody molecule.
  • the saponin is SO1861 or SO1832, more preferably SO1861.
  • An embodiment is the saponin conjugate of the invention, wherein the saponin conjugate is according to formula (XII)a
  • the proteinaceous molecule 1 is an antibody; preferably an anti-CD71 antibody or at least one sdAb capable of binding to CD71.
  • the saponin is SO1861 or SO1832.
  • the saponin derivative moieties comprised by the saponin conjugate are the same.
  • the saponin conjugate comprises preferably 1 or 2 conjugated copies of the dendron-(saponin)8-maleimide1, for which dendron-(saponin)8-maleimide2 as an example dendron-(SO1861)8-maleimide2 is displayed in Figure 5H.
  • the saponin is SO1861 or SO1832, more preferably SO1861.
  • An embodiment is the saponin conjugate of the invention, wherein the saponin conjugate is according to formula (XII)b
  • An embodiment is the saponin conjugate according to formula (SapCon1) (for which an example based on SO1861 is referred to as “mAB-SC-SO1861(DAR4)” in Fig.6):
  • saponin derivative comprised by the saponin conjugate is preferably based on a) saponin selected from any one or more of list A: Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; Saponinum album saponin mixture, or a saponin isolated from Saponinum album; Saponaria officinalis saponin mixture, or a saponin isolated from Saponaria officinalis; and Quillaja bark saponin mixture, or a saponin isolated from Quillaja bark, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; or b) a saponin comprising a gyps
  • the saponin conjugate according to formula (SapCon1) comprises four covalently bound saponin derivatives comprising a semicarbazone functional group.
  • the four saponins on which the saponin derivatives are based are the same.
  • the at least one saponin (here, four saponin copies) on which the saponin derivative comprised by the saponin conjugate is based is any one or more of a saponin selected from list B or C, more preferably from list C.
  • the saponin is SO1861 or SO1832, more preferably SO1861.
  • Figure 6 displays an example of a saponin conjugate according to the formula (SapCon1): four copies of a saponin derivative based on SO1861 comprise the semicarbazone functional group and are linked, via a linker, to Cysteine residues of the monoclonal antibody, typically anti-CD71 antibody.
  • An embodiment is the saponin conjugate according to the invention, wherein the proteinaceous molecule 1 comprises a same first binding site for binding to a first epitope of a first cell-surface molecule.
  • the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule.
  • An embodiment is the saponin conjugate according to the invention, wherein the first binding site of the proteinaceous molecule 1 is selected from any one or more of cell-surface molecule binding-molecules: an amino acid, a peptide, a protein, an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, for example camelid VH, or a ligand for a cell-surface molecule such as a receptor such as EGF and a cytokine, an adnectin, an affibody, an anticalin, or binding molecules comprising one or more of any of these cell-surface molecule binding-molecules.
  • An embodiment is the saponin conjugate according to the invention, wherein the first binding site of the proteinaceous molecule 1 is or comprises a single-domain antibody (sdAb), preferably VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VHH domain such as derived from a heavy- chain only antibody (HCAb) such as from Camelidae origin or Ig-NAR origin such as a variable heavy chain new antigen receptor (VNAR) domain, preferably the HCAb is from Camelidae origin, preferably the sdAb is a VHH domain derived from an HCAb from Camelidae origin (camelid VH) such as derived from an HCAb from camel, lama, alpaca, dromedary, vicuna, guanaco and Bactrian camel.
  • An embodiment is the saponin conjugate according to the invention, wherein the first epitope of the first cell-surface molecule to which the first binding site can bind is a tumor-cell specific first epitope of a first tumor-cell surface molecule, more preferably a tumor-cell specific first epitope of a first tumor-cell surface receptor specifically present on a tumor cell.
  • the first epitope of the first cell-surface molecule, to which the proteinaceous molecule 1 can preferably bind is a tumor-cell specific first epitope of a first tumor-cell surface molecule, more preferably a tumor-cell specific first epitope of a first tumor-cell surface receptor specifically present on a tumor cell.
  • the saponin conjugate according to the invention, wherein the proteinaceous molecule 1 comprises a covalently bound effector moiety, and preferably, said effector moiety is an oligonucleotide.
  • the saponin conjugate comprises the proteinaceous molecule 1 and an oligonucleotide.
  • the saponin conjugate of the invention based on a saponin derivative of the invention and comprising an oligonucleotide, wherein the oligonucleotide comprised by said saponin conjugate is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt.
  • the saponin conjugate further comprises a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme), and/or further comprises a non-proteinaceous molecule such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme).
  • a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme)
  • a non-proteinaceous molecule such as one or more GalNAc
  • the saponin conjugate comprises a non-proteinaceous molecule such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme).
  • the saponin conjugate comprises a non-proteinaceous cell- surface molecule binding molecule (i.e.
  • a non-proteinaceous ligand for a cell-surface molecule such as a cell-surface receptor
  • a non-proteinaceous ligand for a cell-surface molecule such as a cell-surface receptor
  • one or more GalNAc moieties such as 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris.
  • the saponin conjugate of the invention based on a saponin derivative of the invention, wherein the proteinaceous molecule 1 comprised by the saponin conjugate is covalently bound to an oligonucleotide, wherein preferably the oligonucleotide is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt.
  • An aspect of the invention relates to an eighth pharmaceutical composition
  • an eighth pharmaceutical composition comprising the saponin conjugate, wherein the proteinaceous molecule 1 comprised by said conjugate comprises a covalently bound effector moiety, and preferably, said effector moiety is an oligonucleotide, and the eighth pharmaceutical composition optionally comprising a pharmaceutically acceptable excipient and/or diluent.
  • the eighth pharmaceutical composition or the saponin conjugate comprised by said eighth pharmaceutical composition for use as a medicament.
  • the eighth pharmaceutical composition or the saponin conjugate comprised by said eighth pharmaceutical composition, for use in the treatment of a cardiovascular disease or hypercholesterolemia or for use in a method for lowering LDL-cholesterol in the blood of a subject
  • the effector moiety is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, silencing gene apolipoprotein B (apoB), wherein preferably the oligonucleotide is any one of an AON such as a BNA, a xeno nucleic acid, an siRNA, an antisense oligonucleotide.
  • the inventors established that combining in a single conjugate at least one saponin provided with a semicarbazone functional group according to the invention, a binding partner for a cell receptor (i.e. a ligand) such as an antibody or a binding domain or fragment thereof or such as one or more such as three GalNAc moieties for binding ASGPR, and an effector moiety such as an oligonucleotide e.g.
  • a cell receptor i.e. a ligand
  • an effector moiety such as an oligonucleotide e.g.
  • an AON such as a BNA for silencing the HSP27 gene or the apoB gene, provides a conjugate with a higher potency when the activity and effect of the effector moiety in the target cell is considered and compared with the potency and activity achieved with a similar conjugate, though comprising at least one saponin provided with a hydrazone functional group.
  • the improved potency is related to more efficacious release of the saponin moiety from the conjugate due to higher susceptibility for bond cleavage under the slightly acidic pH condition in the endosome of the target cell, when the at least one saponin is provided with the semicarbazone functional group.
  • Examples with an antibody- oligonucleotide conjugate (AOC) comprising at least one saponin provided with the semicarbazone functional group covalently bound to the AOC indeed show the improved gene-silencing effect of this conjugate, compared to the similar conjugate though comprising at least one saponin provided with the hydrazone functional group covalently bound to the AOC.
  • Similar improved potency is achieved when the antibody is replaced by at least one GalNAc moiety, preferably three GalNAc moieties, for binding to the cellular asialoglycoprotein receptor (ASGPR).
  • an embodiment is the saponin conjugate according to the invention, wherein the cell- surface molecule targeting (binding) molecule can bind to a tumor-cell surface molecule, preferably a tumor-cell receptor such as a tumor-cell specific receptor, more preferably a receptor selected from CD71, CD63, CA125, EpCAM(17-1A), CD52, CEA, CD44v6, FAP, EGF-IR, integrin, syndecan-1, vascular integrin alpha-V beta-3, HER2, EGFR, CD20, CD22, Folate receptor 1, CD146, CD56, CD19, CD138, CD27L receptor, PSMA, CanAg, integrin-alphaV, CA6, CD33, mesothelin, Cripto, CD3, CD30, CD239, CD70, CD123, CD352, DLL3, CD25, ephrinA4, MUC1, Trop2, CEACAM5, CEACAM6, HER3, CD74, PTK7, Notch3, FGF2, C4.4A, FL
  • the semicarbazone functional group is hydrolysable (cleavable) under acidic conditions, preferably at pH 4.0 – 6.5, wherein hydrolysis of said semicarbazone functional group provides the aldehyde group on the aglycone core structure of the saponin on which the saponin derivative is based.
  • the saponin in the saponin conjugate is not split off from the conjugate while in the circulation or in tissue.
  • the saponin conjugate is endocytosed by the cell and the saponin conjugate is transferred to and delivered into the cell endosome.
  • the pH is suitable for hydrolysis (cleavage) of the semicarbazone functional group, such that the aldehyde functional group of the saponin on which the saponin conjugate is based, is again formed and the free saponin is provided.
  • the free saponin in the endosome facilitates endosomal escape of any effector molecule or effector moiety into the cytosol, when such effector molecule or effector moiety is co- localized in the endosome.
  • conjugating the saponin to a binding molecule through the semicarbazone functional group e.g., via a maleimide linker
  • the semicarbazone functional group is susceptible to hydrolysis at the endosomal acidic pH, stimulating formation of the aldehyde functional group in the saponin, therewith providing the ‘active’ form of the saponin, when endosomal escape enhancing activity is concerned.
  • any cytotoxicity of the free saponin comprising the aldehyde functional group is not anymore hampering the benefits of the improved delivery of any effector moiety or molecule in the cytosol. That is to say, in the saponin conjugate, cytotoxicity of the saponin is efficiently blocked, inhibited or diminished, when the conjugate circulates or is present in the body extracellularly, and once inside the endosome, the formed free saponin comprising the aldehyde functional group is an efficient molecule for potentiating a desired effect of an effector molecule or moiety (that is for example co- administered to a subject in the form of for example an ADC, AOC, and capable of binding to the same cell as to which the saponin-conjugate of the invention can bind).
  • An embodiment is the saponin conjugate or the saponin derivative according to the invention, wherein the semicarbazone functional group is cleavable or hydrolysable in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ⁇ 5.5, such that the aldehyde group of the saponin on which the saponin derivative is based is formed upon hydrolysis of the semicarbazone functional group.
  • the semicarbazone functional group is cleavable or hydrolysable in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ⁇ 5.5, such that the aldehyde group of the saponin on which the saponin derivative is based is formed upon hydrolysis of the semicarbazone functional group.
  • a specifically preferred embodiment is the saponin derivative according to the invention and/or the saponin conjugate according to the invention, wherein the semicarbazone functional group is subject to hydrolysis in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ⁇ 5.5.
  • the saponin derivative according to the invention in particular the saponin derivative according to formula (XII), comprising the semicarbazone functional group hydrolyses more rapidly and in an higher amount towards the corresponding saponin comprising a “free” aldehyde functional group, i.e.
  • An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to molecule (AA): , wherein represents a saponin moiety according to formula (SM): , wherein R 1 and R 2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23.
  • AA molecule
  • SM saponin moiety according to formula
  • the saponin derivative according to molecule (AA) is particularly suitable for synthesizing saponin conjugates of the invention, comprising either at least one GalNAc moiety, preferably three GalNAc moieties, or an oligonucleotide such as a gene- silencing siRNA or BNA, preferably BNA, or both of at least one GalNAc moiety, preferably three GalNAc moieties and an oligonucleotide such as a gene-silencing siRNA or BNA, preferably BNA.
  • AA saponin derivative according to molecule
  • the inventors now provide the saponin derivative according to molecule (AA) as a semi- product for application in preparing saponin conjugates of the invention, which display enhanced potency with regard to the endosomal escape enhancing activity of the saponin comprised by the conjugate, and which display improved efficacy when the (gene-silencing) effect of an oligonucleotide is considered, when comprised by such a conjugate.
  • Preferred is the saponin derivative according to molecule (BB): , which molecule (BB) is the covalent conjugation product obtained by the covalent conjugation of the saponin derivative according to molecule (AA) as here above described with the tri-functional linker according to formula (XXI): (XXI).
  • Such saponin derivative according to molecule (BB) is a semi-product suitable for providing (or synthesis of) a conjugate comprising the saponin with a semicarbazone functional group, and for example comprising a cell-surface receptor ligand such as one to three, preferably 3 GalNAc moieties, and/or an oligonucleotide such as an AON such as an siRNA or a BNA.
  • a conjugate displays improved potency when the activity of the oligonucleotide is considered, also when the endosomal escape enhancing activity of the saponin is considered.
  • Saponin derivatives of the invention are suitable for conjugation with for example a proteinaceous molecule such as a cell-receptor ligand, an antibody, a binding fragment or domain thereof, such as one or more V HH domains, as outlined here above, as well as for conjugation with for example a non-proteinaceous molecule such as a cell-receptor ligand such as one or more GalNAc moieties, preferably (GalNAc)3Tris.
  • a conjugation provides a saponin conjugate of the invention.
  • the saponin conjugate of the invention based on a saponin derivative of the invention and comprising an oligonucleotide, wherein the oligonucleotide comprised by said saponin conjugate is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt.
  • the saponin conjugate further comprises a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme), and/or further comprises a non-proteinaceous molecule such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme).
  • a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme)
  • a non-proteinaceous molecule such as one or more GalNAc
  • An aspect of the invention relates to saponin conjugate according to molecule (CC): , which molecule (CC) is the covalent conjugation product obtained by the covalent conjugation of the tri-functional linker according to formula (XXI) (as displayed here above) with the saponin derivative according to molecule (AA) as provided here above and with GalNAc conjugate according to molecule (FF): , wherein represents the tri-GalNAc conjugate according to molecule (DD1) or according to molecule (DD2): (DD1), wherein y1, y2 and y3 each are an integer independently selected from 0-20, preferably 1-15, more preferably 2-12, even more preferably 2-10, even more preferably 2-8, most preferably 2 and 3, and preferably y1, y2 and y3 are the same, and y4 is an integer selected from 1-100, preferably 2-80, more preferably 3-70, even more preferably 4-60, even more preferably 4-50, even more preferably 4-40, even more preferably 4-30, even
  • DD2 tri-GalNAc conjugate according to molecule (DD3) or according to molecule (DD4):
  • Such a saponin conjugate according to molecule (CC) is for example a semi-product for preparation of a conjugate further comprising an oligonucleotide such as a gene-silencing BNA or siRNA.
  • the saponin conjugate according to molecule (CC) is suitable for enhancing the effect and potency of for example a gene-silencing oligonucleotide for example provided with (liver) cell-targeting ligand such as an antibody or one or more GalNAc moieties, preferably three, when cells are contacted with both the saponin conjugate according to molecule (CC) and such an AOC or oligonucleotide-GalNAc conjugate.
  • An aspect of the invention relates to saponin conjugate according to molecule (EE): e , which molecule (EE) is the covalent conjugation product obtained by the covalent conjugation of the tri-functional linker according to formula (XXI) (displayed here above) with the saponin derivative according to molecule (AA) as shown here above and with GalNAc conjugate according to molecule (FF) as shown here above and with the oligonucleotide provided with a linker according to molecule (GG): , wherein the molecule (GG) represents the conjugation product of the conjugation reaction between the linker (E)-1-(4-((2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)hexanoyl)hydrazineylidene)methyl)benzamido)-N-(4-(6-methyl-1
  • Such a saponin conjugate according to molecule (EE) of the invention displays a surprisingly improved potency when the endosomal escape enhancing activity of the saponin moiety is considered. It is thought that improved efficacy relates to improved de-coupling (release) of the saponin from the conjugate by cleavage of the semicarbazone functional group under influence of the slightly acidic pH in the endosome of cells which have taken up the conjugate mediated by binding of the conjugate to the ASGPR.
  • An embodiment is the saponin derivative according to the invention wherein the saponin derivative is according to molecule (KK): , wherein represents a saponin moiety according to formula (SM): , wherein R 1 and R 2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide according to any one of the oligosaccharides as listed here above, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23 according to any one of the saponins listed here above, and in Table A1.
  • the saponin derivative according to molecule (KK) is for example a derivative suitable for conjugation with e.g. a cell-targeting antibody, e.g. in the context of an ADC or AOC.
  • Molecule (KK) is applicable as a semi-product for synthesizing such an ADC or AOC, providing a single conjugate comprising the cell-targeting moiety (e.g. an antibody or a binding domain thereof), an effector moiety such as a toxin or a (gene-silencing) oligonucleotide (e.g.
  • an AON such as a BNA or siRNA
  • the saponin moiety with improved activity due to enhanced release from the conjugate under influence of slightly acidic pH in the endosome of a targeted cell, by virtue of the presence of the semicarbazone functional group, and as compared with a similar conjugate though comprising the hydrazone functional group instead of the semicarbazone functional group.
  • the saponin derivative according to molecule (KK) is for example also a semi-product for producing a conjugate comprising more than one copies of the saponin moiety comprising the semicarbazone functional group. Examples are the synthesis of a conjugate comprising for example a G2 dendron or G3 dendron and four or eight covalently bound saponin derivatives comprising the semicarbazone functional group.
  • such a dendron-based conjugate with four or eight saponin moieties is a semi- product for providing a conjugate comprising an effector moiety such as a (gene-silencing) oligonucleotide, such as a BNA or an siRNA, and/or comprising a ligand for a cell-surface molecule such as a cell-receptor binding antibody or binding fragment or domain thereof or a cell-surface receptor ligand such as 1-3 GalNAc moieties for binding to ASGPR, preferably three GalNAc moieties.
  • an effector moiety such as a (gene-silencing) oligonucleotide, such as a BNA or an siRNA
  • a ligand for a cell-surface molecule such as a cell-receptor binding antibody or binding fragment or domain thereof or a cell-surface receptor ligand
  • 1-3 GalNAc moieties for binding to ASGPR, preferably three GalNAc moieties.
  • a gene-silencing oligonucleotide such as a gene-silencing oligonucleotide (an AON), e.g. a BNA.
  • an AON gene-silencing oligonucleotide
  • a certain selected cell-surface molecule such as a receptor
  • a certain cell-surface molecule binding ligand such as an antibody or 1-3 GalNAc moieties
  • a certain effector molecule such as a (gene-silencing) oligonucleotide (e.g.
  • an AON such as a BNA
  • presence of a single saponin derivative comprising the semicarbazone functional group in a conjugate of the saponin derivative, the effector molecule and the cell-surface molecule binding ligand may suffice to obtain optimal potency of the effector molecule, whereas for other combinations more than one saponin derivative moieties in the conjugate may be applied to achieve optimal potency, such as 2-32 saponin derivative moieties, preferably 2-16 moieties, more preferably 4-8 moieties, such as 4 or 8 moieties.
  • the saponin derivatives of the invention provide for a flexible platform when adapting the number of saponin derivative moieties in a saponin conjugate of the invention such that optimal efficacy of the effector molecule is achieved, is considered. Indeed, the inventors established that gene silencing was enhanced when the number of saponin derivative moieties comprising the semicarbazone functional group was increased from 1 to 4 to 8 for a conjugate of the invention comprising three GalNAc moieties and a BNA for silencing the apoB gene (see also the Examples section).
  • An aspect of the invention relates to saponin derivative according to molecule (JJ): which molecule (JJ) is the conjugate product of conjugation of N,N'-((9S,19S)-14-(6- aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo-4,11,14,17- tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide first with the saponin derivative according to molecule (KK), as outlined here above, and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido- 3,6,9,12-tetraoxapentadecan-15-oate.
  • Part of the invention is saponin conjugate according to molecule (LL):
  • LL which molecule (LL) is the covalent conjugation product obtained by the covalent conjugation of the molecule (JJ) as detailed here above with the conjugate of the tri-functional linker and GalNAc according to molecule (MM):
  • molecule (MM) is the conjugate of the tri-functional linker according to formula (XXI) as displayed here above and the GalNAc conjugate according to molecule (NN): , wherein represents the tri-GalNAc conjugate according to molecule (DD1) or molecule (DD2), preferably molecule (DD3) or molecule (DD4), more preferably molecule (DD3) as detailed here above.
  • An aspect of the invention relates to saponin conjugate according to molecule (PP): , which molecule (PP) is the covalent conjugation product obtained by the covalent conjugation of the molecule (LL) as given here above with the oligonucleotide provided with a linker according to molecule (GG) as detailed here above.
  • a saponin conjugate of the invention based on the saponin derivative of the invention, comprising four saponin moieties
  • a saponin conjugate displayed in Fig.40F is the saponin conjugate displayed in Fig.40F as molecule 42.
  • Synthesis of such a saponin conjugate of the invention comprising four saponin moieties is exemplified by the detailed description of the synthesis of molecule 42 (Fig.40F) in the Examples section here below and displayed in Fig. 40.
  • the saponin moieties are linked to the dendron via a linker, wherein each saponin moiety is linked to a linker via a semicarbazone bond. See also the saponin derivative according to molecule (KK), here above.
  • An embodiment is the saponin conjugate of the invention comprising eight saponin moieties.
  • the saponin conjugate of the invention wherein the at least one GalNAc moiety, preferably three GalNAc moieties, the at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 8 saponin moieties, and the oligonucleotide are covalently bound via a tri-functional linker, preferably with each of the GalNAc moiety or GalNAc moieties, the single saponin or the more than one saponin moieties and the oligonucleotide covalently bound to a separate arm of the tri-functional linker.
  • An embodiment is the saponin conjugate of the invention based on the saponin derivative of the invention, comprising eight saponin moieties covalently bound to a dendron, preferably a G3 dendron.
  • a dendron preferably a G3 dendron.
  • An example of such a (G3) dendron is (2S)-N-[(1S)-1- ⁇ [2-(6-amino-N- ⁇ 2-[(2S)-2,6- bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl ⁇ hexanamido)ethyl]carbamoyl ⁇ -5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide.
  • molecule (QQ) is the conjugate product of conjugation of (2S)-N-[(1S)-1- ⁇ [2-(6-amino-N- ⁇ 2- [(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl ⁇ hexanamido)ethyl]carbamoyl ⁇ -5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate first with saponin derivative according to molecule (KK) as detailed here above and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate.
  • An aspect of the invention relates to sap
  • RR which molecule (RR) is the covalent conjugation product obtained by the covalent conjugation of the molecule (QQ) as outlined here above with the conjugate of the tri-functional linker and GalNAc according to molecule (MM) as outlined here above.
  • QQ covalent conjugation of the molecule
  • MM conjugate of the tri-functional linker and GalNAc according to molecule (MM) as outlined here above.
  • SS saponin conjugate according to molecule
  • An embodiment is the saponin conjugate of the invention, wherein the saponin comprised by the conjugate is any one or more of: a) saponin selected from any one or more of list A: - Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; - Gypsophila elegans saponin mixture, or a saponin isolated from Gypsophila elegans; - Saponinum album saponin mixture, or a saponin isolated from Saponinum album; - Saponaria officinalis saponin mixture
  • An embodiment is the saponin conjugate of the invention, wherein the saponin is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS- 7, SA1641, a saponin isolated from Saponaria officinalis, Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; preferably wherein the saponin is any one or more of QS-21, SO1832, SO1861, SA1641 and GE1741; more preferably wherein the saponin is QS-21, SO1832 or SO1861; most preferably being SO1861.
  • the saponin is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS- 7, SA1641, a saponin isolated from Saponaria officinalis
  • An embodiment is the saponin conjugate of the invention, wherein the saponin is a saponin isolated from Saponaria officinalis, preferably wherein the saponin is any one or more of Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; more preferably wherein the saponin is any one or more of SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; even more preferably wherein the saponin is any one or more of SO1832, SO1861 and SO1862; even more preferably wherein the saponin is SO1832 and SO1861; most preferably being SO1861.
  • An embodiment is the saponin derivative according to the invention, and for example according to any one of the molecules (AA), (BB), (KK), (JJ) and (QQ) or saponin conjugate according to the invention and according to any one of the molecules (CC), (EE), (LL), (PP), (RR) and (SS), wherein the saponin derivative or the saponin conjugate is based on a saponin according to any one of the saponins listed here above and in Table A1.
  • the saponin derivative according to the invention and for example according to any one of the molecules (AA), (BB), (KK), (JJ) and (QQ) or the saponin conjugate according to the invention and according to any one of the molecules (CC), (EE), (LL), (PP), (RR) and (SS), wherein the saponin derivative or the saponin conjugate is based on a saponin selected from SO1861, SO1832 and QS-21, preferably SO1861 and SO1832, more preferably SO1861.
  • the saponin derivative according to the invention and for example according to any one of the molecules (AA), (BB), (KK), (JJ) and (QQ) or the saponin conjugate according to the invention and according to any one of the molecules (CC), (EE), (LL), (PP), (RR) and (SS), wherein the semicarbazone functional group is subject to hydrolysis in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ⁇ 5.5.
  • a saponin conjugate of the invention based on the saponin derivative of the invention, comprising eight saponin moieties is the saponin conjugate displayed in Fig.41D as molecule 47.
  • Synthesis of such a saponin conjugate of the invention comprising eight saponin moieties is exemplified by the detailed description of the synthesis of molecule 47 (Fig.41D) in the Examples section here below and displayed in Fig. 41.
  • the saponin moieties are linked to the dendron via a linker, wherein each saponin moiety is linked to a separate linker via a semicarbazone bond. See also the saponin derivative according to molecule (KK), here above.
  • the saponin conjugate of the invention based on the saponin derivative of the invention, comprising one saponin moiety, or 4 saponin moieties, preferably 4 saponin moieties covalently bound to a dendron, preferably a G2 dendron such as for example N,N'-((9S,19S)-14- (6-aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo-4,11,14,17- tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide), or 8 saponin moieties, preferably 8 saponin moieties covalently bound to a dendron, preferably a G3 dendron such as for example (2S)-N-[(1S)-1- ⁇ [2-(6-amino-N- ⁇ 2-[(2S)-2,6-bis[(2S)-2,6-bis((2
  • An embodiment is the saponin conjugate according to the invention and for example according to any one of the molecules (EE), (PP) and (SS), wherein the saponin derivative on which the saponin conjugate is based, is a saponin derivative formed upon derivatization of a saponin according to any one of the saponins listed here above and in Table A1.
  • Preferred is the saponin conjugate according to the invention and for example according to any one of the molecules (EE), (PP) and (SS), wherein the saponin conjugate is based on a saponin selected from SO1861, SO1832 and QS-21, preferably SO1861 and SO1832, more preferably SO1861 or SO1832.
  • SO1861 the saponin derivative according to molecule (VII)a:
  • (VII)a is conjugated with an oligonucleotide and with at least one GalNAc moiety, preferably 3 GalNAc moieties, to provide a saponin conjugate of the invention.
  • An embodiment is the saponin conjugate of the invention, wherein the saponin is SO1861, and wherein the saponin conjugate is provided by conjugation of SO1861 saponin derivative according to molecule (VII)a: (VII)a with an oligonucleotide and with at least one GalNAc moiety, preferably 3 GalNAc moieties, to provide the saponin conjugate.
  • An embodiment is the saponin conjugate according to the invention and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is any one of an AON, a BNA, a xeno nucleic acid, an siRNA, an antisense oligonucleotide.
  • the saponin conjugate is based on the saponin derivative according to the invention.
  • An embodiment is the saponin conjugate according to the invention and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is selected from any one or more of a(n): short interfering RNA (siRNA), short hairpin RNA (shRNA), anti-hairpin-shaped microRNA (miRNA), single-stranded RNA, aptamer RNA, double-stranded RNA (dsRNA), anti-microRNA (anti-miRNA, anti-miR), antisense oligonucleotide (ASO), DNA, antisense DNA, locked nucleic acid (LNA), bridged nucleic acid (BNA), 2’-O,4’- aminoethylene bridged nucleic acid (BNA NC ), BNA-based siRNA, and BNA-based antisense oligonucleotide (BNA-AON).
  • siRNA short interfering RNA
  • the saponin conjugate of the invention based on a saponin derivative of the invention and comprising an oligonucleotide, wherein the oligonucleotide comprised by said saponin conjugate is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, preferably being 8 – 100 nt, most preferably being 10 – 50 nt.
  • An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is selected from any one or more of a(n): anti-miRNA, a BNA-AON or an siRNA, such as BNA-based siRNA, selected from chemically modified siRNA, metabolically stable siRNA and chemically modified, metabolically stable siRNA.
  • a(n): anti-miRNA, a BNA-AON or an siRNA such as BNA-based siRNA, selected from chemically modified siRNA, metabolically stable siRNA and chemically modified, metabolically stable siRNA.
  • An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, silencing any one of genes: apolipoprotein B (apoB), HSP27, transthyretin (TTR), proprotein convertase subtilisin/kexin type 9 (PCSK9), TMPRSS6, delta-aminolevulinate synthase 1 (ALAS1), anti-thrombin 3 (AT3), glycolate oxidase (GO), complement component C5 (CC5), X gene of hepatitis B virus (HBV), S gene of HBV, alpha-1 antitrypsin (AAT), miR-122, hepatitis B virus
  • An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, silencing any one of genes: apolipoprotein B (apoB) and HSP27.
  • An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, targeting an mRNA involved in expression of any one of proteins: apoB, HSP27, TTR, PCSK9, TMPRSS6, ALAS1, AT3, GO, CC5, expression product of X gene of HBV, expression product of S gene of HBV, AAT, miR-122, hepatitis B virus HbsAg, LDHA, CEBPA and LDH, or is capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, antagonizing or restoring an miRNA function such as inhibiting an oncogenic miRNA (onco
  • An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, targeting an mRNA involved in expression of any one of proteins: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AAT, miR-122, hepatitis B virus HbsAg, LDHA and CEBPA.
  • the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, targeting an mRNA involved in expression of any one of proteins: HSP27, apoB, TTR, PCSK9, TMPRSS6, A
  • An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, targeting an mRNA involved in expression of any one of proteins: apoB and HSP27.
  • compositions comprising a saponin conjugate
  • a second pharmaceutical combination comprising: (a) a fourth pharmaceutical composition comprising the saponin conjugate of the invention and optionally a pharmaceutically acceptable excipient and/or diluent; and (b) a fifth pharmaceutical composition comprising a conjugate comprising a cell-surface molecule binding-molecule, such as a second proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety, wherein the proteinaceous molecule 2 is the same or different from the proteinaceous molecule 1 present in the saponin conjugate, and if the proteinaceous molecule 2 is different from the proteinaceous molecule 1, the proteinaceous molecule 2 comprising a second binding site for binding to a second epitope of a second cell-surface molecule, wherein the second cell-surface molecule is the same as or different from the first cell surface molecule, and if the second cell-surface molecule is different from the first cell surface molecule, the second cell-
  • the effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based.
  • the effector moiety is not the saponin derivative or the saponin conjugate of the invention.
  • the inventors have found that the saponin derivatives according to the invention which are used as a component for potentiating the intracellular effect of an effector molecule or effector moiety when the effector molecule is provided as a conjugate comprising a cell-surface molecule binding-molecule such as an antibody, e.g.
  • an ADC or AOC are now also suitably for (covalent) coupling to a cell-surface molecule binding-molecule such as a cell-surface molecule targeting antibody, such as an sdAb, such that by such coupling the saponin conjugate of the invention is provided, endowed with, for example, anti-tumor activity potentiating activity when used in combination with for example an ADC or an AOC.
  • a cell-surface molecule binding-molecule such as a cell-surface molecule targeting antibody, such as an sdAb
  • An embodiment is the fourth pharmaceutical composition according to the invention comprising the saponin conjugate according to the invention, preferably a pharmaceutically acceptable diluent, and further comprising: ⁇ a pharmaceutically acceptable salt, preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganese, potassium, sodium, strontium, or zinc salt, preferably NaCl; and/or ⁇ a pharmaceutically acceptable buffer system, such as a phosphate, a borate, a citrate, a carbonate, a histidine, a lactate, a tromethamine, a gluconate, an aspartate, a glutamate, a tartarate, a succinate, a malate, a fumarate, an acetate and/or a ketoglutarate containing buffer system.
  • a pharmaceutically acceptable salt preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganese, potassium,
  • An embodiment is the fourth pharmaceutical composition according to the invention comprising the saponin conjugate according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and has a pH within the range of 2-11, preferably within the range of 4-9, more preferably within the range of 6-8.
  • An embodiment is the first pharmaceutical composition of the invention, wherein the saponin conjugate is the saponin conjugate according to formula (XII).
  • An embodiment is the second pharmaceutical combination of the invention, comprising: (a) the fourth pharmaceutical composition of the invention comprising the saponin conjugate of the invention, wherein the first epitope on the first cell-surface molecule is a tumor-cell specific first epitope on a first tumor cell-specific surface molecule, preferably a tumor-cell specific first epitope on a first cell-surface receptor specifically present on a tumor cell; and (b) the fifth pharmaceutical composition of the invention, wherein the second cell-surface molecule is a second tumor cell-specific surface molecule which is the same or different from the first tumor cell-specific surface molecule, preferably a second cell-surface receptor specifically present on a tumor cell which is the same or different from the first cell-surface receptor specifically present at said tumor cell, and wherein the second epitope is a tumor-cell specific second epitope, wherein the first epitope and the second epitope, which is the same as or different from the first epitope, are exposed on the same cell.
  • An aspect of the invention relates to a third pharmaceutical combination, comprising: (a) the fourth pharmaceutical composition of the invention comprising the saponin conjugate according to the invention, comprising the first binding site for binding to the first epitope on the first cell-surface molecule, the fourth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent; and (b) a sixth pharmaceutical composition comprising a conjugate comprising a cell-surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, wherein the proteinaceous molecule 3 comprises the first binding site for binding to the first epitope on the cell-surface molecule of (a), the sixth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent, wherein the first binding site of the proteinaceous molecule 1 and the first binding site of the proteinaceous molecule 3 are the same, and wherein the first cell-surface molecule and the first epitope on the first cell
  • the effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based.
  • the effector moiety is not the saponin derivative or the saponin conjugate of the invention.
  • An embodiment is the sixth pharmaceutical composition according to the invention, further comprising: ⁇ a pharmaceutically acceptable salt, preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganese, potassium, sodium, strontium., or zinc salt, preferably NaCl; and/or ⁇ a pharmaceutically acceptable buffer system, such as a phosphate, a borate, a citrate, a carbonate, a histidine, a lactate, a tromethamine, a gluconate, an aspartate, a glutamate, a tartrate, a succinate, a malate, a fumarate, an acetate and/or a ketoglutarate containing buffer system.
  • An embodiment is the sixth pharmaceutical composition according to the invention comprising the saponin conjugate according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and has a pH within the range of 2-11, preferably within the range of 4-9, more preferably within the range of 6-8.
  • An embodiment is the second pharmaceutical combination or the third pharmaceutical combination according to the invention, wherein the proteinaceous molecule 2 and the proteinaceous molecule 3 is of a type as detailed or the proteinaceous molecule 1, e.g.
  • an antibody or an antigen binding fragment or antigen binding domain thereof a ligand for a cell-surface molecule or cell-surface receptor such as EGF or a cytokine, an scFv, a Fab, a binding molecule comprising an sdAb, such as a VHH, a binding molecule comprising any of an adnectin, an anticalin, an affibody.
  • any cell-surface molecule binding- molecule can be selected and is suitable for application in the saponin conjugates of the invention and for application in the pharmaceutical compositions and combinations of the invention, that is known today in the technological field of (specifically) targeting a mammalian (aberrant, tumor, auto- immune, etc.) cell with a binding molecule, e.g. for (targeted and specific) delivery of an effector molecule or effector moiety conjugated to the cell-surface molecule binding-molecule.
  • Suitable cell-surface molecule binding-molecules are the antibodies and binding fragments, binding domains and binding derivatives thereof and ligands such as EGF or cytokines used today to deliver drug molecules, payloads, effector moieties, protein toxins, small-molecule toxins, enzymes, oligonucleotides, etc., etc., e.g. in ADCs and AOCs.
  • Any cell-surface molecule binding-molecule applicable for e.g. designing and providing ADCs and AOCs is typically also applicable for providing the saponin conjugate of the invention (e.g., proteinaceous molecule 1).
  • ADCs and AOCs are typically also applicable for providing the cell-surface molecule binding-molecule conjugated with an effector moiety, e.g. the proteinaceous molecule 3 and proteinaceous molecule 2 conjugated to an effector moiety.
  • an effector moiety e.g. the proteinaceous molecule 3 and proteinaceous molecule 2 conjugated to an effector moiety.
  • any cell-surface molecule binding-molecule can be selected and is suitable for application in the saponin conjugates of the invention and for application in the pharmaceutical compositions and combinations of the invention, that is known today in the technological field of (specifically) targeting a mammalian (aberrant, tumor, auto-immune, etc.) cell with a binding molecule, e.g.
  • any of the cell-surface molecule binding-molecules proteinaceous molecule 1, proteinaceous molecule 2, proteinaceous molecule 3 can be replaced by a non- proteinaceous cell-surface molecule binding-molecule suitable for targeting (binding to) a selected and desired cell such as a mammalian cell, e.g. a tumor cell or an autoreactive immune cell (autoimmune cell).
  • a mammalian cell e.g. a tumor cell or an autoreactive immune cell (autoimmune cell).
  • the cell-surface molecules to which combinations of the proteinaceous molecule 1, proteinaceous molecule 2, proteinaceous molecule 3 bind are present at the surface of the same target cell, when combinations of proteinaceous molecule 1, proteinaceous molecule 2 and proteinaceous molecule 3 bind to different cell-surface molecules.
  • proteinaceous molecule 1 binds to HER2 and proteinaceous molecule 2 binds to CD71 or EGFR
  • HER2 and CD71 or HER2 and EGFR are typically present at the same cell.
  • An embodiment is the second pharmaceutical combination or the third pharmaceutical combination according to the invention, wherein the second binding site of the proteinaceous molecule 2 and the first binding site of the proteinaceous molecule 3 is/are or comprise(s) a single- domain antibody (sdAb), preferably VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VHH domain such as derived from a heavy-chain only antibody (HCAb) such as from Camelidae origin or Ig-NAR origin such as a variable heavy chain new antigen receptor (VNAR) domain, preferably the HCAb is from Camelidae origin, preferably the sdAb is a VHH domain derived from an HCAb from Camelidae origin (camelid VH) such as derived from an HCAb from camel, lama, alpaca, d
  • An embodiment is the second pharmaceutical combination or the third pharmaceutical combination according to the invention, wherein the second epitope of the second cell-surface molecule to which the second binding site can bind is a tumor-cell specific second epitope of a second tumor-cell surface molecule, more preferably a tumor-cell specific second epitope of a second tumor-cell surface receptor specifically present on a tumor cell, and wherein the first epitope of the first cell-surface molecule is a tumor-cell specific first epitope of a first tumor-cell surface molecule, more preferably a tumor-cell specific first epitope of a first tumor-cell surface receptor specifically present on a tumor cell, wherein the second cell-surface molecule and the first cell- surface molecule are present on the same cell.
  • An embodiment is the second pharmaceutical combination or the third pharmaceutical combination according to the invention, wherein the second and third cell-surface molecule binding (targeting) molecule can bind to a tumor-cell surface molecule, preferably a tumor-cell receptor such as a tumor-cell specific receptor, more preferably a receptor selected from CD71, CD63, CA125, EpCAM(17-1A), CD52, CEA, CD44v6, FAP, EGF-IR, integrin, syndecan-1, vascular integrin alpha- V beta-3, HER2, EGFR, CD20, CD22, Folate receptor 1, CD146, CD56, CD19, CD138, CD27L receptor, PSMA, CanAg, integrin-alphaV, CA6, CD33, mesothelin, Cripto, CD3, CD30, CD239, CD70, CD123, CD352, DLL3, CD25, ephrinA4, MUC1, Trop2, CEACAM5, CEACAM6, HER3, CD74, PTK7, Notch3, FGF
  • An aspect of the invention relates to a third pharmaceutical combination, comprising: (a) the fourth pharmaceutical composition of the invention and (b) the sixth pharmaceutical composition of the invention, wherein the first cell-surface molecule is expressed on a tumor cell surface, and preferably the first cell-surface molecule is a tumor cell-specific surface molecule, and wherein preferably the first epitope is a first tumor-cell specific epitope.
  • the second pharmaceutical combination or third pharmaceutical combination comprises or consists of an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, for example camelid VH, or a ligand for a cell-surface molecule such as a receptor such as EGF and a cytokine, preferably VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immuno
  • an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab
  • An aspect of the invention relates to a seventh pharmaceutical composition
  • a seventh pharmaceutical composition comprising: (a) the saponin conjugate of the invention; and (b) the conjugate comprising proteinaceous molecule 2 and an effector moiety of the invention, or the conjugate comprising proteinaceous molecule 3 and an effector moiety of the invention, and optionally further comprising a pharmaceutically acceptable excipient and/or diluent.
  • the effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based.
  • the effector moiety is not the saponin derivative or the saponin conjugate of the invention.
  • An embodiment is the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, wherein the effector moiety that is comprised by the conjugate comprising a cell-surface molecule binding- molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety or that is comprised by the conjugate comprising a cell-surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, comprises or consists of any one or more of: an oligonucleotide, a nucleic acid and a xeno nucleic acid, preferably selected from any one or more of a vector, a gene, a cell suicide inducing transgene, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), anti-sense oligonucleotide (ASO, AON), short interfering RNA (siRNA), microRNA (miRNA), DNA
  • An embodiment is the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, wherein the effector moiety that is comprised by the conjugate comprising a cell-surface molecule binding- molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety or that is comprised by the conjugate comprising a cell-surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, comprises or consists of any one or more of: at least one proteinaceous molecule, preferably selected from any one or more of a peptide, a protein, protein toxin, an enzyme such as urease and Cre-recombinase, a ribosome-inactivating protein, and more preferably selected from any one or more of a viral toxin such as apoptin; a bacterial toxin such as Shiga toxin, Shiga-like toxin, Pse
  • dianthin-30 or dianthin-32 saporin e.g. saporin-S3 or saporin-S6, bouganin or de-immunized derivative debouganin of bouganin, shiga-like toxin A, pokeweed antiviral protein, ricin, ricin A chain, modeccin, modeccin A chain, abrin, abrin A chain, volkensin, volkensin A chain, viscumin, viscumin A chain; or an animal or human toxin such as frog RNase, or granzyme B or angiogenin from humans, or any fragment or derivative thereof; preferably the protein toxin is dianthin and/or saporin.
  • saporin e.g. saporin-S3 or saporin-S6, bouganin or de-immunized derivative debouganin of bouganin, shiga-like toxin A, pokeweed antiviral protein, ricin, ricin A chain, modeccin, modeccin A
  • An embodiment is the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, wherein the effector moiety that is comprised by the conjugate comprising a cell-surface molecule binding- molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety or that is comprised by the conjugate comprising a cell-surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, comprises or consists of any one or more of: at least one payload, preferably selected from any one or more of a toxin targeting ribosomes, a toxin targeting elongation factors, a toxin targeting tubulin, a toxin targeting DNA and a toxin targeting RNA, more preferably any one or more of emtansine, pasudotox, maytansinoid derivative DM1, maytansinoid derivative DM4, monomethyl auristatin
  • An aspect of the invention relates to the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, for use as a medicament.
  • An aspect of the invention relates to the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, for use in the treatment or prevention of a cancer or of an autoimmune disease such as rheumatoid arthritis.
  • An aspect of the invention relates to a ninth pharmaceutical composition comprising the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), and optionally a pharmaceutically acceptable excipient and/or optionally a pharmaceutically acceptable diluent.
  • An aspect of the invention relates to the ninth pharmaceutical composition of the invention or to the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use as a medicament.
  • An aspect of the invention relates to the ninth pharmaceutical composition of the invention or to the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use in the treatment or prophylaxis of a disease or health problem in which an expression product is involved of any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AT3, GO, CC5, X gene of HBV, S gene of HBV, AAT, miR-122, hepatitis B virus HbsAg, LDHA, CEBPA and LDH, and/or for use in the treatment or prophylaxis of a disease or health problem which involves any one or more of genes: HSP27, apoB, TTR
  • An aspect of the invention relates to the ninth pharmaceutical composition of the invention or to the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use in the treatment or prophylaxis of a disease or health problem in which an expression product is involved of any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AAT, miR-122, hepatitis B virus HbsAg, LDHA and CEBPA, and/or for use in the treatment or prophylaxis of a disease or health problem which involves any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AAT, miR-122, hepatitis B virus HbsAg, LDHA and CEBPA.
  • An embodiment is the ninth pharmaceutical composition of the invention or the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use as here above outlined, wherein said use is in the treatment or prophylaxis of a disease or health problem in which an expression product is involved of any one or more of genes: HSP27 and apoB, preferably apoB, and/or for use in the treatment or prophylaxis of a disease or health problem which involves any one or more of genes: HSP27 and apoB, preferably apoB.
  • An embodiment is the ninth pharmaceutical composition of the invention or the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use as here above outlined, for use in the treatment or prophylaxis of a cancer, an infectious disease, a viral infection, hypercholesterolemia, cardiovascular disease, primary hyperoxaluria, haemophilia A, haemophilia B, AAT related liver disease, acute hepatic porphyria, TTR-mediated amyloidosis, hereditary TTR amyloidosis (hATTR), complement-mediated disease, hepatitis B infection, hepatitis C infection, ⁇ 1-antitrypsin deficiency, ⁇ -thalassaemia, or an auto- immune disease.
  • a cancer an infectious disease, a viral infection, hypercholesterolemia, cardiovascular disease, primary hyperoxaluria, haemophilia A, haemophilia B, AAT related liver disease,
  • An embodiment is the ninth pharmaceutical composition of the invention or the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use as here above outlined, wherein said use is in the treatment or prophylaxis of a cancer such as endometrial carcinoma, breast cancer, lung cancer or hepatocellular carcinoma, and/or a cardiovascular disease such as hypercholesterolemia, preferably hypercholesterolemia.
  • An aspect of the invention relates to the ninth pharmaceutical composition of the invention or to the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use in the lowering of LDL-cholesterol in a subject.
  • the saponin of the saponin derivative and the saponin conjugate based on the saponin derivative is a saponin derived from a plant.
  • the saponin on which the saponin derivative is based and the saponin comprised by the saponin conjugate of the invention is preferably a saponin isolated from a plant.
  • the term ‘plant’ is to be understood to include plants and trees.
  • the saponin is isolated from the root of a plant or from the bark of a tree. Examples of such plants from which the saponin is derived (isolated) are Quillaja saponaria, Gypsophila paniculate L., Saponaria officinalis such as Saponaria officinalis L.
  • the saponin derivative and the saponin conjugate comprise a single type of saponin, preferably a single type of saponin derived from plant material such as the roots of a plant, such as SO1861, SO1862 or SO1832 from Saponaria officinalis (e.g., Saponaria officinalis L.) (roots) or such as a QS-21, a QS-7 or a QS-17 from Quillaja saponaria (roots).
  • Suitable sources for isolating saponins according to the invention i.e.
  • Saponin suitable for the saponin derivative of the invention and for the saponin conjugate of the invention are thus for example: Quillaja saponaria saponin, saponin isolated from Quillaja saponaria, for example Quil-A, QS-17- api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl, Saponinum album, saponin isolated from Saponinum album, Saponaria officinalis saponin, saponin isolated from Saponaria officinalis (preferred), Quillaja bark saponin, saponin isolated from Quillaja bark saponin, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21, QS-21
  • the individual saponins present in QS-21 are suitable saponins for the saponin derivative and the saponin conjugate of the invention, i.e. the saponins depicted as the saponins of SCHEME Q:
  • An embodiment is the saponin derivative of the invention, or the saponin conjugate of the invention, wherein the saponin on which the saponin derivative is based or on which the saponin conjugate is based, is isolated from a plant.
  • the saponin is isolated from a part of a plant, such as the root, or from a part of a tree, such as the bark.
  • the saponin is isolated from roots derived from a plant.
  • EGF-dianthin was produced from E.coli according to standard procedures.
  • HSP27BNA oligo and ApoB and ApoB#02 were produced by Bio-Synthesis Inc, (Lewisville).
  • Tris(2-carboxyethyl)phosphine hydrochloride (TCEP, 98%, Sigma-Aldrich), 5,5- Dithiobis(2-nitrobenzoic acid) (DTNB, Ellman’s reagent, 99%, Sigma-Aldrich), ZebaTM Spin Desalting Columns (2 mL, Thermo-Fisher), NuPAGETM 4-12% Bis-Tris Protein Gels (Thermo- Fisher), NuPAGETM MES SDS Running Buffer (Thermo-Fisher), NovexTM Sharp Pre-stained Protein Standard (Thermo-Fisher), PageBlueTM Protein Staining Solution (Thermo-Fischer), PierceTM BCA Protein Assay Kit (Thermo-Fisher), N-Ethy
  • LC-MS method 1 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, mass ranges depending on the molecular weight of the product: neg or neg/pos within in a range of 1500-2400 or 2000-3000; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Acquity C18, 50 ⁇ 2.1 mm, 1.7 ⁇ m Temp: 60oC, Flow: 0.6 mL/min, lin.
  • LC-MS method 1, 3 Apparatus Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, neg/pos 1500-2400; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Acquity C18, 50 ⁇ 2.1 mm, 1.7 ⁇ m Temp: 60oC, Flow: 0.6 mL/min, lin.
  • UPIBSM UPISMFTN with SO
  • UPCMA PDA: UPPDATC, 210-320 nm
  • SQD ACQ-SQD2 ESI
  • ELSD gas pressure 40 psi
  • drift tube temp 50°C
  • column Waters XSelect TM CSH C18, 50 ⁇ 2.1 mm, 2.5 ⁇ m
  • Temp 40°C
  • Flow 0.5 mL/min
  • Gradient: t 0min 5% A
  • t2.0min 98% A
  • t2.7min 98% A
  • Eluent A 0.1% formic acid in acetonitrile
  • Eluent B 0.1% formic acid in water.
  • LC-MS method 1, 4 Apparatus Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, neg/pos 1500-2400; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Acquity C18, 50 ⁇ 2.1 mm, 1.7 ⁇ m Temp: 60oC, Flow: 0.6 mL/min, lin.
  • UPIBSM UPISMFTN with SO
  • UPCMA PDA: UPPDATC, 210-320 nm
  • SQD ACQ-SQD2 ESI
  • ELSD gas pressure 40 psi
  • drift tube temp 50°C column: Waters Acquity Shield RP18, 50 ⁇ 2.1 mm, 1.7 ⁇ m
  • Temp 25oC
  • Flow 0.5 mL/min
  • Gradient: t 0min 5% A
  • t2.0min 98% A
  • t2.7min 98% A
  • Eluent A acetonitrile
  • TNBS assay Glycine standards (0, 2.5, 5, 10, 15 and 20 ⁇ g/ml) were freshly prepared using DPBS pH 7.5.
  • TNBS assay reagent was prepared by combining TNBS (40 ⁇ l) and DPBS pH 7.5 (9.96 ml).10% w/v SDS was prepared using DI water. For the assay, 60 ⁇ l of each sample (singlicate) and standard (triplicate) were plated out. To each well was added TNBS reagent (60 ⁇ l) and incubated on a plate shaker for 3 hours at 37°C and 600rpm. Afterwards, 50 ⁇ l of 10% SDS and 25 ⁇ l 1M HCl were added and the plate optical density was analysed at 340 nm.
  • Lysine-targeting molecule incorporation determined by depletion of lysine concentration of conjugate with respect to unmodified protein.
  • SEC The conjugates were analysed by SEC using an Akta Purifier 10 system and Biosep SEC-s3000 column eluting with DPBS:IPA (85:15). Conjugate purity was determined by integration of the conjugate UV absorbance peak versus integrated impurities/aggregate forms UV absorbance peaks.
  • SDS-PAGE and Western Blotting Native proteins and conjugates were analysed under heat denaturing non-reducing and reducing conditions by SDS-PAGE against a protein ladder using a 4-12% bis-tris gel and MES as running buffer (200V, ⁇ 40 minutes).
  • Samples were prepared to 0.5 mg/ml, comprising LDS sample buffer and MOPS running buffer as diluent. For reducing samples, DTT was added to a final concentration of 50 mM. Samples were heat treated for 2 minutes at 90-95°C and 5 ⁇ g (10 ⁇ l) added to each well. Protein ladder (10 ⁇ l) was loaded without pre-treatment. Empty lines were filled with 1 ⁇ LDS sample buffer (10 ⁇ l). After the gel was run, it was washed thrice with DI water (100 ml) with shaking (15 minutes, 200 rpm). Coomassie staining was performed by shaker-incubating the gel with PAGEBlue protein stain (30 ml) (60 minutes, 200 rpm).
  • Samples were prepared to 0.5 mg/ml, and BNA standard was prepared to 20 ⁇ g/ml, respectively, all comprising TBE Urea sample buffer and purified H 2 O as diluent. Samples and standards were heat treated for 3 minutes at 70°C and 10 ⁇ l added to each well, equating to 5 ⁇ g of protein and conjugate samples, and 0.2 ⁇ g of BNA, per lane. Oligo ladder reconstituted to 0.1 ⁇ g/band/ml in TE pH 7.5 (2 ⁇ l) was loaded without pre- treatment. After the gel was run, it was stained with freshly prepared ethidium bromide solution (1 ⁇ g/ml) with shaking (40 minutes, 200 rpm).
  • the resulting gel was visualised by UV epi-illumination (254 nm), imaged and then further processed using ImageJ.
  • MALDI-TOF-MS MALDI-TOF spectra were recorded on a MALDI-Mass Spectrometer (Bruker Ultrafex III).
  • the sample dissolved in MilliQ water in nanomolar to micromolar range was spotted on the target (MTP 384 target plate polished steel T F, Bruker Daltons) using either super-DHB (99%, Fluka) or sinapinic acid (SA, 99%, Sigma-Aldrich) as the matrix dissolved in acetonitrile (MADLI-TOF-MS tested, Sigma) / 0.1% TFA (7:3 v/v) via the dried-droplet-method.
  • PepMix Peptide Calibration Standard, Bruker Daltons
  • ProteMass Protein Calibration Standard, Sigma-Aldrich
  • the background signal of ‘medium only‘ wells was subtracted from the signal from all other wells before the ratio of untreated/treated cells was calculated by dividing the background corrected signal of treated wells by the background corrected signal of the untreated wells (multiplied by 100 for percentage viability relative to untreated reference wells).
  • FACS analysis Cells were seeded in DMEM (PAN-Biotech GmbH) supplemented with 10% fetal calf serum (PAN- Biotech GmbH) and 1% penicillin/streptomycin (PAN-Biotech GmbH), at 500,000 c/plate in 10 cm dishes and incubated for 48 hrs (5% CO2, 37 ⁇ C) until a confluency of 90% was reached.
  • the cells were trypsinized (TryplE Express, Gibco Thermo Scientific) to obtain a single cell suspension. 0.75 x 10 6 Cells were transferred to a 15 mL Falcon tube and centrifuged (1,400 rpm, 3 min). The supernatant was discarded while leaving the cell pellet submerged. The cell pellet was resuspended and cells were washed with 4 mL cold PBS (Mg 2+ and Ca 2+ free, 2% FBS). After washing, the cells were resuspended in 3 mL cold PBS (Mg 2+ and Ca 2+ free, 2% FBS) and divided equally over 3 round bottom FACS tubes (1 mL/tube).
  • the cells were centrifuged again and resuspended in 200 ⁇ L cold PBS (Mg 2+ and Ca 2+ free, 2% FBS) or 200 ⁇ L antibody solution containing 5 ⁇ L antibody in 195 ⁇ L cold PBS (Mg 2+ and Ca 2+ free, 2% FBS).
  • APC Mouse IgG1, ⁇ APC anti-human EGFR was used to stain the EGFR receptor.
  • PE anti-human HER2 APC anti-human CD340 (erbB2/HER-2) (#324408 Biolegend ) was used to stain the HER2 receptor and PE Mouse IgG2a, ⁇ Isotype Ctrl FC (#400212, Biolegend) was used as its matched isotype control.
  • PE anti- human CD71 (#334106, Biolegend) was used to stain the CD71 receptor and PE Mouse IgG2a, ⁇ Isotype Ctrl FC (#400212, Biolegend) was used as its matched isotype control. Samples were incubated for 30 min at 4 °C on a tube roller mixer.
  • Fluorescence yields were recorded on a Fluoroskan Ascent FL (Thermo Scientific) at an excitation wavelength of 355 nm and an emission wavelength of 460 nm.6 ⁇ g at a concentration of 75.86 ⁇ M of ANS were used per sample and measurement.
  • Haemolysis assay Human red blood cells (RBCs) were isolated from a buffy coat using a Ficoll gradient. The RBC packed cells ( ⁇ 4-5 ml) were washed 2x with 50 ml DPBS without Ca 2+ /Mg 2+ (PAN-Biotech GmbH). Cells were pelleted by centrifugation for 10 min, 800xg at RT.
  • RBC were counted and resuspended at 500.000.000 c/ml in DPBS (without Ca 2+ /Mg 2+ ), based on total cell count.
  • SO1861-linker dilutions were prepared in DPBS (with Ca 2+ /Mg 2+ , PAN-Biotech GmbH), at 1.11x final strength.
  • a 0.02% Triton-X100 solution was prepared in DPBS +/+ .135 ⁇ l of all compounds was dispensed per well in a 96 well V-bottom plate. To this, 15 ⁇ l RBC suspension was added and mixed shortly (10 sec - 600 rpm). The plate was then incubated a further 30 min at RT, with gentle agitation.
  • RNA isolation and gene expression analysis RNA from cells was isolated and analysed according to standard protocols (Biorad).
  • Dendron-(EMCH-SO1861)4-maleimide1 ( Figure 4 g) Dendron(SO1861)4-amine (8.12 mg, 0.891 ⁇ mol) and 2,5-dioxopyrrolidin-1-yl 1-(2,5-dioxo-2,5- dihydro-1H-pyrrol-1-yl)-3,6,9,12-tetraoxapentadecan-15-oate (3.94 mg, 8.91 ⁇ mol) were dissolved in DMF(1.00 mL). Next, DIPEA (1.55 ⁇ L, 8.91 ⁇ mol) was added and the mixture was shaken for 1 min and left standing at room temperature. After 3 hours, the reaction mixture was subjected to preparative LC-MS.
  • the resulting residue was dissolved in a mixture of 20 mM NH4HCO3 with 0.5 mM TCEP/acetonitrile (3:1, v/v, 3.242 mL). From this solution, 1000 ⁇ L was directly added to SO1861-EMCH (14.4 mg, 6.94 ⁇ mol, 4.5 equiv. compared to the scaffold) and the mixture was shaken for 1 min and left standing at room temperature. After 10 min, the reaction mixture was lyophilized overnight.
  • Boc-Lys(Boc)-ONp (3.36 g, 7.18 mmol) was added and the reaction mixture was stirred at room temperature overnight.
  • the reaction mixture was evaporated in vacuo and the residue was purified by flash chromatography (DCM - methanol/DCM (1/9, v/v) gradient 100:0 rising to 0:100) to give the title product (2.71 g, 100%) as a white solid. Purity based on LC-MS 97%. LRMS (m/z): 807 [M-198] 2+ LC-MS r.t.
  • Dendron-(semicarbazone-SO1861)8-azide Dendron-(semicarbazone-SO1861)8-amine (5.4 mg, 0.28 ⁇ mol, molecule 44) and 2,5- dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate (1.1 mg, 2.8 ⁇ mol, molecule 18) were dissolved in DMF(1.00 mL). Next, DIPEA (1.302 ⁇ L) was added and the mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.
  • Dendron(SO1861)8-amine (17 mg, 0.891 ⁇ mol) and 2,5-dioxopyrrolidin-1-yl 1-(2,5-dioxo-2,5- dihydro-1H-pyrrol-1-yl)-3,6,9,12-tetraoxapentadecan-15-oate (3.94 mg, 8.91 ⁇ mol) were dissolved in DMF(1.00 mL). Next, DIPEA (1.55 ⁇ L, 8.91 ⁇ mol) was added and the mixture was shaken for 1 min and left standing at room temperature. After 3 hours, the reaction mixture was subjected to preparative LC-MS.
  • Dendron(SO1861)8-amine (27 mg, 1.4 ⁇ mol) and 2,5-Dioxopyrrolidin-1-yl 3-(2-(2-(3-(2,5-dioxo-2h- pyrrol-1(5h)-yl)propanamido)ethoxy)ethoxy)propanoate (5.84 mg, 0.014 mmol) were dissolved in DMF (1.00 mL). Next, DIPEA (2.39 ⁇ L, 0.014 mmol) was added and the suspension was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.
  • cetuximab-(SC-SO1861) 4 The procedure is exemplary described for cetuximab-(SC-SO1861) 4 : to a solution of cetuximab (40 mg, 8.0 ml) was added 10 ⁇ l/ml each of Tris concentrate (127 mg/ml, 1.05 M), Tris.HCl concentrate (623 mg/ml, 3.95 M) and EDTA-Na2 concentrate (95 mg/ml, 0.26 M) to give a 50 mM TBS, 2.5 mM EDTA buffer pH 7.5.
  • BNA (9.5 mg, 1.6 ⁇ 10 -3 mmol, 9.59 mg/ml) was added an aliquot of freshly prepared TCEP solution (50.0 mg/ml, 10 mole equivalents, 16.3 ⁇ 10 -3 mmol) in TBS pH 7.5, the mixture briefly vortexed then incubated for 60 minutes at 37 °C with roller-mixing. After, the mixture was desalted using a PD10 G25 desalting column eluted with TBS pH 7.5, followed by repeated washing via diafiltration using vivaspin T43K MWCO filters (3,000, 20 ⁇ C, ⁇ 15 minutes) and TBS pH 7.5 (seven cycles in total) to remove residual TCEP.
  • To Tras-SMCC (4.93 mg, 3.3 ⁇ 10 -5 mmol, 2.127 mg/ml) was added an aliquot of BNA-SH (8.0 mole equivalents, 26.3 ⁇ 10 -5 mmol, 3.098 mg/ml, 0.499 ml), the mixture vortexed briefly then incubated overnight at 20 ⁇ C. After ca.
  • the conjugate was purified by gel filtration using a 1.6 ⁇ 35 cm Sephadex G50M column eluted with DPBS pH 7.5.
  • the conjugate was collected, pooled and concentrated to ca.1 ml.
  • the concentrate was analysed by BCA assay to ascertain antibody concentration and then by UV-vis spectrophotometry to ascertain a combined mass based extinction coefficient ⁇ value for the conjugate and incorporation of BNA.
  • the product was normalised to 2.0 mg/ml and spin-filtered to 0.2 ⁇ m.
  • cetuximab-(SC-SO1861)4-(BNA)2 cetuximab-(SC-SO1861)-(BNA) (DAR4/DAR2) comprising four copies of the SO1861 and two copies of the BNA.
  • This exemplary conjugate is tested for its influence on HSP27 expression in A431 cells (See Figure 22).
  • the conjugate mixture was again UV analysed to confirm PDT displacement by HSP27BNA and was then purified using a 2.6 ⁇ 26 cm Sephadex G50M column eluted with DPBS pH 7.5 to give purified Cet-(SC- SO1861)4 – HSP27BNA conjugate.
  • the aliquot was analysed by BCA colorimetric assay and assigned a new molar absorptivity, then concentrated and normalised to 2.5 mg/ml, filtered to 0.2 ⁇ m and then dispensed into an aliquot for characterisation (retain) and two aliquots for product testing, one supplied refrigerated and the other frozen.
  • HSP27BNA oligonucleotide sequences HSP27 (5’-GGCacagccagtgGCG-3’) [SEQ ID NO: 1], more specifically BNA NC , modified from Zhang et al.
  • BNA NC oligos were ordered with 5’-Thiol C6 linker at Bio-Synthesis Inc (Lewisville, Texas), with BNA bases in capitals, and fully phosphorothioated backbones.
  • hCD71mab-EMCH-SO1861 hCD71mab was desalted into TBS pH 7.5 buffer and then normalised to 3 mg/ml.
  • hCD71mab 7.52 mg, 3.007 mg/ml, 5.1 ⁇ 10 -5 mmol
  • TCEP solution 2.0 mg/ml, 4 mole equivalents, 20.4 ⁇ 10 -5 mmol
  • a ca.1 mg (0.340 ml) aliquot of hCD71mab-SH was removed from the mixture and purified by gel filtration using a zeba spin desalting column into TBS pH 7.5.
  • hCD71mab-SC-SO1861 ( Figure 6)
  • hCD71 (55.1 mg, 0.37 ⁇ mol, 8.10 mg/ml, 6.80 ml) as supplied was buffered exchanged using a zeba spin desalting column eluting with TBS pH 7.5, and normalised to 3 mg/ml.
  • To hCD71 50 mg, 0.33 ⁇ mol, 5.044 mg/ml was added an aliquot of freshly prepared TCEP solution (2.00 mg/ml, 3 mole equivalents, 1 ⁇ mol), the mixture vortexed briefly then incubated for 210 minutes at 20°C with roller-mixing.
  • hCD71mab-dendron(EMCH-SO1861)4 ( Figure 7) hCD71 (55.1 mg, 0.37 ⁇ mol, 8.10 mg/ml, 6.80 ml) as supplied was buffered exchanged using a zeba spin desalting column eluting with TBS pH 7.5, and normalised to 5 mg/ml.
  • hCD71 50 mg, 0.33 ⁇ mol, 5.044 mg/ml was added an aliquot of freshly prepared TCEP solution (2.00 mg/ml, 3 mole equivalents, 1 ⁇ mol), the mixture vortexed briefly then incubated for 210 minutes at 20 °C with roller-mixing. After incubation (prior to addition of Dendron-(EMCH-SO1861)4-maleimide1), a 1.0 mg (0.201 ml) aliquot of hCD71 solution was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5.
  • hCD71- dendron(EMCH-SO8161)4 mixture 0.4 mg aliquot of hCD71- dendron(EMCH-SO8161)4 mixture was removed, purified by gel filtration using zeba spin desalting column into TBS pH 7.5 and characterised by Ellman’s assay alongside positive and negative controls to obtain Dendron-(EMCH-SO1861)4 incorporation.
  • To the bulk hCD71- Dendron-(EMCH- SO1861)4 mixture was added an aliquot of freshly prepared NEM solution (5 mole equivalents, 1.4 ⁇ mol of a 2.5 mg/ml solution) to quench the reaction.
  • the conjugate was purified by zeba 40K MWCO spin desalting columns eluted with DPBS pH 7.5 to give purified hCD71-SO1861 conjugate.
  • hCD71mab-dendron(SC-SO1861)8 ( Figure 8) hCD71 (55.1 mg, 0.37 ⁇ mol, 8.10 mg/ml, 6.80 ml) as supplied was buffered exchanged using a zeba spin desalting column eluting with TBS pH 7.5, and normalised to 3 mg/ml. To hCD71 (50 mg, 0.33 ⁇ mol, 5.044 mg/ml) was added an aliquot of freshly prepared TCEP solution (1 mg/ml, 1.3 mole equivalents, 0.43 ⁇ mol), the mixture vortexed briefly then incubated for 210 minutes at 20 °C with roller-mixing.
  • cetuximab (5.85 mg, 4.793 mg/ml, 3.9 ⁇ 10 -5 mmol) was added an aliquot of freshly prepared TCEP solution (2.72 mole equivalents, 1.1 ⁇ 10 -4 mmol, 30.4 ⁇ g, 30.4 ⁇ l of a 1 mg/ml solution), the mixture vortex mixed briefly then incubated for 210 minutes at 20 °C with roller-mixing. After incubation (prior to addition of Dendron-(EMCH- SO1861)4-maleimide1), a 1 mg (0.214 ml) aliquot of Ab-SH was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5.
  • the product was concentrated then normalised to 2.50 mg/ml using a vivaspin T4 concentrator (3,000 g, 5°C, 30 minutes).
  • Tris concentrate 127 mg/ml, 1.05M
  • Tris.HCl concentrate 623 mg/ml, 3.95M
  • EDTA.2Na.2H 2 O concentrate 95 mg/ml, 0.26M
  • cetuximab (78.1 mg, 4.739 mg/ml, 5.2 ⁇ 10- 4 mmol) was added an aliquot of freshly prepared TCEP solution (1.647 mole equivalents, 8.6 ⁇ 10- 4 mmol, 245 ⁇ g, 245 ⁇ l of a 1 mg/ml solution), the mixture vortex mixed briefly then incubated for 90 minutes at 20°C with roller-mixing. After incubation (prior to addition of Dendron-(EMCH- SO1861)4-maleimide1), a 2 mg (0.428 ml) aliquot of Ab-SH was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5.
  • the product was concentrated then normalised to 2.50 mg/ml using a vivaspin T4 concentrator (3,000 g, 5°C, 30 minutes).
  • This TTE mix was pre-tested against histidine pH 6.0 buffer (30 ⁇ l/ml) to yield a final pH 7.53 at 19°C.
  • An aliquot of cetuximab (10 mg, 6.70 ⁇ 10 -5 mmol, 4.793 mg/ml) was added an aliquot of freshly prepared TCEP solution (1.00 mg/ml, 1.24 mole equivalents, 8.30 ⁇ 10 -5 mmol, 24 ⁇ l), the mixture vortexed briefly then incubated for 210 minutes at 20 °C with roller-mixing.
  • the aliquot was concentrated by vivaspin T15 centrifugal filtration (3,000 g, 10 minute intervals, 20°C), analysed by UV-vis spectrophotometry and BCA assay to ascertain a new EC280 and normalised to 2.5 mg/ml, filtered to 0.2 ⁇ m and then dispensed into aliquots for in-house characterisation and customer testing.
  • Example 1 Results SO1861-SC-Mal (blocked) ( Figure 2B; Molecule (VIII)) was tested for pH dependent release with a release kinetics assay and compared with SO1861-EMCH (blocked) ( Figure 3). SO1861-EMCH (blocked) was produced in same way as in Figure 2B. The assay was performed in buffers with pH 7.4, pH 6.0 pH, pH 5.0, or pH 4.0 at 37 ⁇ C for 24 hours.
  • SO1861, SO1861-EMCH, SO1861-SC and SO1861-SC-Mal were titrated in the presence of a suboptimal, fixed concentration (Figure 21) of 5 pM EGFdianthin (Dia-EGF), 50 pM trastuzumab-saporin, 10 pM CD71-saporin or 10 pM cetuximab- saporin on EGFR/HER2 expressing cells (HeLa and A431, Table 1, 3, 4).
  • SO1861, SO1861-EMCH or SO1861- SC-Mal were titrated on a fixed, suboptimal concentration (determined in Figure 13A) of 50 nM trastuzumab-S-HSP27BNA, an antisense (BNA) oligonucleotide targeting heat-shock protein 27 (HSP27) conjugated to trastuzumab lysines via a stable linker (S) with a DAR 2, in A431 cells (HER2 +/- ) (Table 1, Figure 13B).
  • BNA antisense oligonucleotide targeting heat-shock protein 27 conjugated to trastuzumab lysines via a stable linker (S) with a DAR 2, in A431 cells (HER2 +/- ) (Table 1, Figure 13B).
  • CMC critical micelle concentration
  • SO1861-semicarbazone-Mal (SO1861-SC-Mal) was conjugated via cysteine residues (Cys) to cetuximab (a monoclonal antibody binding human EGFR), with a DAR 4, to yield cetuximab-(SC- SO1861) 4 as depicted in Figure 6.
  • Cetuximab-(SC-SO1861) 4 was titrated on a fixed, suboptimal concentration (see Figure 21) of 10 pM CD71mab-saporin (monoclonal antibody binding human CD71; clone OKT-9, conjugated to the protein toxin saporin).
  • cetuximab-(SC-SO1861) 4 or cetuximab-(EMCH-SO1861) 4 could not induce any cell killing activity in EGFR ++ /CD71 + expressing cells.
  • cetuximab-(EMCH-SO1861) 4 more potently enhances endosomal escape of the CD71mab conjugated protein toxin (the same concentration of 10 pM the protein toxin is not effective in the absence of saponin; see Figure 21), thereby inducing efficient cell killing of EGFR ++ /CD71 + expressing cells.
  • Improved acid-sensitive linker release of SO1861 from an antibody at low pH in endosomes thus improves the efficacy of delivery of a protein toxin such as a ribosomal inactivating protein toxin to the cytoplasm by mAb-SO1861 conjugates.
  • cetuximab-(SC-SO1861) 4 was titrated alongside a fixed concentration of 10 pM CD71mab-saporin, and targeted protein toxin-mediated cell killing was determined on HeLa (Table 1;EGFR +/- /CD71 + ) and A2058 (Table1, EGFR-/CD71 + ) cells.
  • SO1861 concentrations required to induce endosomal escape and cytoplasmic delivery of the protein toxin are not reached (i.e., below threshold), demonstrating enhanced delivery efficiency does not increase delivery to untargeted cells and therefore maintain target selectivity.
  • SO1861-SC-Mal was conjugated via cysteine residues (Cys) to trastuzumab (monoclonal antibody binding human HER2), with a DAR 4, to yield trastuzumab-(SC-SO1861) 4 .
  • trastuzumab-(SC-SO1861) 4 was titrated along a fixed concentration of 10 pM CD71mab-saporin on JIMT-1 (Table1; HER2 +/- /CD71 + ) and MDA-MB-468 (Table 1; HER2-/CD71 + ).
  • targeted protein toxin-mediated cell killing was determined.
  • MDA-MB-468 cells that lack HER2 receptor expression
  • CD71mab-(SC-SO1861) SO1861-SC-Mal or Dendron-(SC-SO1861)8-Mal was conjugated via cysteine residues (Cys) to CD71mab (a monoclonal antibody binding human CD71) to yield CD71mab-(SC-SO1861) (DAR4.2) or CD71mab-dendron(SC-SO1861)8 (DAR 1.5).
  • CD71mab-(SC-SO1861) (DAR4.2) or CD71mab-dendron(SC-SO1861)8 (DAR 1.5, on average 12 SO1861 molecules, as depicted in Figure 8A, 8B) or CD71mab-(EMCH-SO1861) (DAR3.8) or CD71mab-dendron(EMCH-SO1861)4 (DAR 3.2, on average 12 SO1861 molecules; as depicted in Figure 7A, 7B) was titrated in combination with a fixed suboptimal concentration (see Figure 21) of 5 pM DianthinEGF (Dia-EGF; dianthin protein toxin fused to EGF).
  • Targeted protein toxin mediated cell killing potency was determined on CD71+/EGFR+ expressing cells (Table 1; SK-BR-3 (CD71 + /EGFR + ), JIMT-1 (CD71 + /EGFR + ), HeLa (CD71 + /EGFR + ), MDA-MB-468 (CD71 + /EGFR + ), A431 (CD71 + /EGFR + ) as well as on A2058 (CD71 + /EGFR-) ( Figure 23).
  • Improved release of SO1861 from from SC-linked CD71 receptor targeted monoclonal antibody in the endosome thus improves the delivery of a protein toxin such as a ribosomal inactivating protein toxin to the cytoplasm as compared to EMCH-linked CD71 conjugates.
  • a protein toxin such as a ribosomal inactivating protein toxin
  • EXAMPLE 2 The inventors have previously established that numerous aberrant or diseased cells such as tumor cells can be targeted with a conjugate comprising a ligand such as EGF or an antibody and comprising a saponin such as a saponin as listed in Table A1, without wishing to be bound by any theory, resulting in the endocytosis of the conjugate and the accumulation of the saponin in the endosome of the targeted cell, facilitating the endosomal escape of a molecule such as an oligonucleotide or a proteinaceous toxin, which is present in said same cell in the same endosomes at the same time, from the endosome and into the cytosol of the targeted cell.
  • a conjugate comprising a ligand such as EGF or an antibody and comprising a saponin such as a saponin as listed in Table A1
  • a conjugate comprising a ligand such as EGF or an antibody and comprising a saponin such as a saponin as listed
  • an endocytic receptor was targeted, such as EGFR, HER2 and CD71.
  • CD71 is preferred.
  • the conjugates comprised a monoclonal antibody capable of binding to such an endocytic cell-surface receptor on the target cell, or comprised at least one sdAb binding such a receptor.
  • suitable endocytic receptor targeting ligands and antibodies were EGF, VHH capable of binding to HER2, VHH capable of binding to CD71, VHH capable of binding to EGFR, MoAb capable of binding to CD71, MoAb capable of binding to HER2 such as trastuzumab and pertuzumab, MoAb capable of binding to EGFR such as cetuximab and matuzumab.
  • the saponin comprised by the conjugate was any one of SO1861, SA1641, GE1741, QS- 21, QS-21A, QS21-B, Quil-A, SO1832, SO1904, and SO1862.
  • the inventors have previously successfully established that oligonucleotides such as BNA HSP27 and proteinaceous toxins such as saporin and dianthin are efficiently endocytosed and released from endosomes into the cell cytosol under influence of a conjugate comprising a saponin according to Table A1.
  • the saponin moieties were for example linked to an antibody involving a hydrazone bond formed at the C-23 position, i.e.
  • Such saponin-bearing conjugate was for example co-administered with a second conjugate such as an ADC or an AOC.
  • a second conjugate such as an ADC or an AOC.
  • the saponin was covalently bound (e.g., via the hydrazone bond) to such an ADC or AOC, which also resulted in enhanced activity of the effector molecule comprised by the ADC or AOC, once present inside the target cell.
  • This is referred to as the 1-component approach.
  • Illustrative examples of such 2-component combinations are for example published in international applications WO2020126627, WO2021261995, and WO2021259925.
  • Illustrative examples of such 1-component conjugates are for example published in international application WO2020126620.
  • CD71 is a suitable target for delivery of saponin and/or effector moiety into a target cell such as an aberrant or diseased cell.
  • oligonucleotide is a suitable effector molecule to be delivered in a target cell and into the cytosol of said cell, under influence of a saponin-bearing conjugate.
  • TABLE T1 published examples of a conjugate comprising a saponin and a cell-targeting ligand, wherein the saponin is not linked with the ligand via a semicarbazone bond, said conjugate combined with a second conjugate comprising a cell-targeting ligand and an effector moiety, and published examples of 1-component conjugates comprising a cell-targeting ligand, an effector moiety and a saponin, wherein the saponin is not linked via a semicarbazone bond in the 1- component conjugate.
  • TFA trifluoroacetic acid TFL trifunctional linker Analytical methods LC-MS method 1 Apparatus: Waters IClass; Bin.
  • UPIBSM UPISMFTN with SO
  • UPCMA PDA: UPPDATC, 210-320 nm
  • SQD ACQ-SQD2 ESI
  • ELSD gas pressure 40 psi
  • drift tube temp 50°C
  • column Acquity C18, 50 ⁇ 2.1 mm, 1.7 ⁇ m Temp: 60oC
  • Flow 0.6 mL/min, lin.
  • UPIBSM UPISMFTN with SO
  • UPCMA PDA: UPPDATC, 210-320 nm
  • SQD ACQ-SQD2 ESI
  • ELSD gas pressure 40 psi
  • drift tube temp 50°C
  • column Waters XSelect TM CSH C18, 50 ⁇ 2.1 mm, 2.5 ⁇ m
  • Temp 25°C
  • Flow 0.5 mL/min
  • Gradient: t 0min 5% A
  • t2.0min 98% A
  • t2.7min 98% A
  • Eluent A acetonitrile
  • UV-vis spectrophotometry Protein concentrations were determined using a Thermo Nanodrop 2000 spectrophotometer and the following mass based extinction coefficient ⁇ 280 values ((mg/ml)-1 cm-1); Oligo concentrations were determined using a molar extinction coefficient ⁇ 260 value of 153,000 M-1 cm-1. Ellman’s assay was carried out using a Perkin Elmer Lambda 25 Spectrophotometer and a literature molar extinction coefficient ⁇ 412 value of 14150 M-1 cm-1 for TNB.
  • Samples were prepared to 0.5 mg/ml, comprising LDS sample buffer and MOPS running buffer as diluent. For reducing samples, DTT was added to a final concentration of 50 mM. Samples were heat treated for 2 minutes at 90-95°C and 5 ⁇ g (10 ⁇ l) added to each well. Protein ladder (10 ⁇ l) was loaded without pre-treatment. Empty lines were filled with 1 ⁇ LDS sample buffer (10 ⁇ l). After the gel was run, it was washed thrice with DI water (100 ml) with shaking (15 minutes, 200 rpm). Coomassie staining was performed by shaker-incubating the gel with PAGEBlue protein stain (30 ml) (60 minutes, 200 rpm).
  • Samples were prepared to 0.5 mg/ml, and BNA standard was prepared to 20 ⁇ g/ml, respectively, all comprising TBE Urea sample buffer and purified H 2 O as diluent. Samples and standards were heat treated for 3 minutes at 70°C and 10 ⁇ l, equating to 5 ⁇ g of protein and conjugate samples, and 0.2 ⁇ g of BNA, were added per lane. Oligo ladder reconstituted to 0.1 ⁇ g/band/ml in TE pH 7.5 (2 ⁇ l) was loaded without pre-treatment. After the gel was run, it was stained with freshly prepared ethidium bromide solution (1 ⁇ g/ml) with shaking (40 minutes, 200 rpm).
  • the resulting gel was visualised by UV epi-illumination (254 nm), imaged and then further processed using ImageJ.
  • MALDI-TOF-MS MALDI-TOF spectra were recorded on a MALDI-Mass Spectrometer (Bruker Ultrafex III).
  • the sample dissolved in MilliQ water in nanomolar to micromolar range was spotted on the target (MTP 384 target plate polished steel T F, Bruker Daltons) using either super-DHB (99%, Fluka) or sinapinic acid (SA, 99%, Sigma-Aldrich) as the matrix dissolved in acetonitrile (MADLI-TOF-MS tested, Sigma) / 0.1 % TFA (7:3 v/v) via the dried-droplet-method.
  • PepMix Peptide Calibration Standard, Bruker Daltons
  • ProteMass Protein Calibration Standard, Sigma-Aldrich
  • Trifunctional linker-(L-hydrazone-SO1861)- (L-BNA oligo) – (Trivalent-GalNAc) synthesis ( Figure 36)
  • the trifunctional linker (TFL) has the IUPAC name: 5,8,11,18,21,24,27-Heptaoxa-2,14,30- triazatritriacontanoic acid, 14-[16-(11,12-didehydrodibenz[b,f]azocin-5(6H)-yl)-13,16-dioxo-3,6,9- trioxa-12-azahexadec-1-yl]-33-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)-15,31-dioxo-, (1R,4E)-4- cycloocten-1-yl ester.
  • the trifunctional linker has the following formula (XXI): Intermediate 1: SO1861-L-hydrazone-azide (molecule 3) To SO1861 (60 mg, 0.032 mmol, molecule 1) and 1-azido-3,6,9,12-tetraoxapentadecane-15- hydrazide (39.3 mg, 0.129 mmol, molecule 2) was added methanol (extra dry, 1.00 mL) and TFA (9.86 ⁇ l, 0.129 mmol). The reaction mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative MP- LC.
  • the trivalent GalNAc-amine formate is obtained based on the trivalent GalNAc-azide which is the Intermediate 7 as shown in Fig.35D.
  • the formate of molecule 6 is not shown for simplicity.
  • the reaction mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was evaporated in vacuo and the residue was dissolved in a mixture of 0.1% formic acid in water and 0.1% formic acid in acetonitrile (9:1, v/v, 1 mL). The resulting solution was directly subjected to preparative MP- LC. 2B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (13.0 mg, 66%) as a white solid.
  • reaction mixture was added to a freshly prepared solution of TFL-(DBCO)-(TCO)-(Maleimide) (20.6 mg, 6.13 ⁇ mol, molecule 5) in 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 2.00 mL). The resulting mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative MP-LC. 2A Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (3.83 mg, 21%) as a white solid. Purity based on LC-MS 89%.
  • reaction mixture was shaken for 1 min and left standing at room temperature. After 30 min, the reaction mixture was frozen and lyophilized overnight to yield the crude title product as a pink fluffy solid.
  • To the crude product was added a solution of 20 mM ammonium bicarbonate (1.50 mL) and the resulting suspension was filtered over a 0.45 ⁇ m syringe filter. The filtrate was lyophilized overnight to yield the title product (3.4 mg, 89%) as a pink fluffy solid. Purity based on LC-MS 90%.
  • reaction mixture was shaken for 1 min and left standing at room temperature. After 30 min, the reaction mixture was added to a freshly prepared solution of trifunctional linker (7.39 mg, 6.13 ⁇ mol, molecule 4) in 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 2.00 mL). The resulting mixture was shaken for 1 min and then left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative MP-LC. 2A Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (3.83 mg, 21%) as a white solid. Purity based on LC-MS 89%.
  • reaction mixture was shaken for 1 min and then left standing at room temperature. After 30 min, the reaction mixture was added to a freshly prepared solution of TFL-(L-semicarbazone-SO1861)-(TCO)-(maleimide) (20.4 mg, 6.13 ⁇ mol, molecule 29) in 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 2.00 mL). The resulting mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative MP-LC. 2A Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (16.7 mg, 54%) as a white solid. Purity based on LC-MS 94%.
  • reaction mixture was stirred at room temperature. After 30 min, the reaction mixture was evaporated in vacuo and co-evaporated with dichloromethane (2 ⁇ 50 mL). Next, the residue was dissolved in dichloromethane (100 mL) and resulting solution was stirred at 0°C. A solution of Boc hydrazine (2.33 mL, 15.0 mmol) in dichloromethane (20 mL) and DiPEA (3.83 mL, 22.0 mL) was added, and the reaction mixture was stirred overnight at room temperature.
  • Trifunctional linker-(dendron(-L- semicarbazone -SO1861)8)- BNA oligo - Trivalent-GalNAc synthesis ( Figure 41) Intermediate 25: dendron(L-semicarbazone-SO1861) 8 -amine (molecule 44) (2S)-N-[(1S)-1- ⁇ [2-(6-amino-N- ⁇ 2-[(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl ⁇ hexanamido)ethyl]carbamoyl ⁇ -5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate (0.61 mg, 0.299 ⁇ mol, molecule 43) was dissolved in a mixture
  • TCO blocking on TFL has been performed on the following conjugates: TFL-(L-hydrazone-SPT001)-(blocked TCO)-(trivalent GalNAc) (molecule 51) TFL-(dendron (L-hydrazone-SPT001)4)-(blocked TCO)-(trivalent GalNAc) (molecule 52) TFL-(dendron-(L-hydrazone-SPT001)8)-(blocked TCO)-(trivalent GalNAc) (molecule 53) TFL-(L-semicarbazone-SPT001)-(blocked TCO)-(trivalent GalNAc) (molecule 54) TFL-(dendron((L-semicarbazone-SPT001)4)-(blocked TCO)-(trivalent GalNAc) (molecule 55) TFL-(dendron(L-semicarbazone-SPT001)8)-(blocked TCO)-(trivalent GalNAc) (molecule 56) The procedure is exemplary described for TFL-(
  • a conjugate according to the invention comprising a single GalNAc moiety, has been synthesized and tested.
  • Luminescence based cell viability assay Cell Titer Glo - CTG
  • Cells were incubated for 72 hr at 37°C following compound addition before the cell viability was determined according to the manufacturer’s instruction (CellTiter-Glo® 2.0 Cell Viability Assay, Promega). Briefly, the plate was first equilibrated to RT for 30 minutes. Next, 120 ⁇ L CTG solution was added to each well containing 120 ⁇ L media. The plate briefly mixed (10 sec, 600 rpm) and incubated for approximately 10 minutes in the dark at RT.
  • the luminescence signal was measured on a Spectramax ID5 plate reader (Molecular Devices).
  • the background signal of wells containing only medium was subtracted from all other well values before the cell viability percentage of treated/untreated cells was calculated by dividing the background corrected signal of treated wells by the background corrected signal of the untreated wells (x 100 for percentage).
  • Human primary hepatocyte treatment Cryopreserved primary human hepatocytes (Cytes Biotechnologies S.L., Spain) were thawed in hepatocyte thawing media (Cytes Biotechnologies S.L., Spain). Cells were re-suspended in hepatocyte plating media (Cytes Biotechnologies S.L., Spain).
  • Cells were seeded onto collagen-I coated plates at a density of 215.600 cells/well or 66.600 cells/well for 48 or 96-well plates, respectively (Greiner BioOne). Cells were pre-cultured for 4-6 hrs at 37°C allowing for cell attachment to cell culture plates before test compounds were added. Plating medium was replaced by 315 ⁇ l or 108 ⁇ l maintenance media (Cytes Biotechnologies S.L., Spain), after which conjugates were added from a 10x concentrated stock solution in PBS. Plates were incubated for 72 hr at 37°C before being harvested for gene expression and cell viability analysis.
  • BNA bridged- nucleic acid
  • PE anti-human CD71 (#334106, Biolegend) was used to stain the transferrin receptor, PE Mouse IgG2a, ⁇ Isotype Ctrl FC (#400212, Biolegend) was used as its matched isotype control.
  • PE anti-human ASGPR1 (#130-122-963, Miltenyi) was used to stain the ASGPR1 receptor and PE Mouse IgG1, Isotype Ctrl (#130-113-762, Miltenyi) was used as its matched isotype control. Samples were incubated for 30 min at 4°C.
  • RNA isolation and gene expression analysis from primary mouse and human hepatocytes RNA from cells was isolated using TRI Reagent® Solution (Thermo Scientific) according to the manufacturer’s instruction. Conversion into cDNA was performed using iScriptTM cDNA Synthesis Kit (BioRad) using standard protocols. ApoB expression levels and levels of specific hepatocyte housekeeping genes were determined using quantitative real-time PCR assays (qRT-PCR) using iTaqTM Universal SYBR® Green Supermix (BioRad) and the Light Cycler 480 (Roche Diagnostics, Rotnch, Switzerland) with gene specific DNA primers, listed in Table A4.
  • trivalent (GalNAc)3-SO1861 (EMCH) was co-administered at 5 ml/kg in the tail vain (i.v.) right after the trivalent GalNAc-ApoB conjugate.
  • Animals were weighed weekly and clinical observations were performed 2 – 3 times daily within the first 48 hrs, and at least once daily thereafter until study end. - Sampling of serum, liver, and kidney tissue.
  • post-dose timepoints e.g., 24 hrs, 72 hrs, 196 hrs, 336 hrs, 672 hrs post dose
  • serum was generated from the collected blood for biomarker analysis, using standard procedures.
  • 3 animals per timepoint per treatment group (6 animals in the vehicle control group in study A) were sacrificed to collect terminal bleeds and collect relevant organs, such as liver and kidney tissues for further analyses.
  • One half of the liver and one kidney was frozen and used for tissue RNA analysis. Table A5.
  • ApoB expression levels and levels of specific liver housekeeping genes were determined using quantitative real-time PCR assays (qRT-PCR) using iTaqTM Universal SYBR® Green Supermix (BioRad) and the Light Cycler 480 (Roche Diagnostics, Rotnch, Switzerland) with gene specific DNA primers, listed in Table A4 (study A) and Table A7 (study B), respectively. Analysis was done by the ⁇ Ct method to determine ApoB expression relative to 2 liver-specific housekeeping control mRNAs. Each analysis reaction was performed in triplicate. Table A7.
  • Covalent binding of the saponin to the GalNAc/oligonucleotide conjugate via a semicarbazone bond thus results in increased efficacy when relative apoB mRNA levels are compared with levels in cells treated with a conjugate where saponin was linked to the GalNAc/oligonucleotide conjugate via a hydrazone bond.
  • improved efficacy of the release of free saponin from the conjugate, when the conjugate is transferred into the endosome is at the basis for the improved potency of the oligonucleotide, as obtained with the conjugate comprising saponin bound via semicarbazone.
  • Covalent binding of the saponin to the GalNAc/oligonucleotide conjugate via a semicarbazone bond thus results in increased efficacy when relative apoB mRNA levels are considered and compared with levels measured for control animals which were treated with conjugate comprising saponin linked via a hydrazone bond to the GalNAc/oligonucleotide conjugate.
  • improved efficacy of the release of free saponin from the conjugate, when the conjugate is transferred into the endosome is at the basis for the improved potency of the oligonucleotide, as obtained with the conjugate comprising saponin bound via semicarbazone.
  • the co-administration group of 10-fold less payload i.e., 0.1 mg/kg (GalNAc)3-ApoB#02 + 5 mg/kg (GalNAc)3-SO1861 still showed 25% decrease.
  • NB levels for 0.1 mg/kg ApoB#02 (196 hrs), 0.01 mg/kg (GalNAc)3-ApoB + 5 mg/kg (GalNAc)3- SO1861 (196 hrs and 336 hrs) and 0.1 mg/kg (GalNAc)3-ApoB + 5 mg/kg (GalNAc)3-SO1861 (196 hrs) are not reported.
  • the observed serum apoB protein reduction (shown in Figure 26) translated also to a reduction in serum LDL-cholesterol (LDL-C) levels.
  • Targeted (GalNAc)3-ApoB#02 at a dose of 1 mg/kg reduced LDL-C to an average of 2.7 mg/dl within 24 hrs already (n 3 animals), i.e., a 53% reduction compared to vehicle and ApoB#02 BNA groups.
  • mice in treatment groups gained weight comparable to the mice receiving vehicle.
  • a decrease of saponin amount (0.1 mg/kg (GalNAc)3-SO1861 (sc) + 0.1 mg/kg (GalNAc)3-ApoB#02) yielded less potency (122 ⁇ g/ml apoB protein).
  • mice in treatment groups gained weight comparable to the mice receiving vehicle. Serum ALT levels were determined and results are shown in Figure 33.
  • this data shows that the saponin conjugates are well tolerated in the doses and dose regimen applied, and particularly, that administration of SO1861-containing conjugates (GalNAc)3- SO1861-ApoB#02 (sc), (GalNAc)3-d(SO1861)4-ApoB#02 (sc), and (GalNAc)3-d(SO1861)8- ApoB#02 (sc), as well as co-administration of (GalNAc)3-SO1861 with (GalNAc)3-ApoB#02 has no immediate tolerability issues, while showing high potency in the C57BL/6J mouse model.

Abstract

The invention relates to a saponin derivative based on a saponin comprising a triterpene aglycone and at least one of a first saccharide chain and a second saccharide chain linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde functional group which has been transformed to a semicarbazone functional group. The invention also relates to a first pharmaceutical composition comprising the saponin derivative of the invention. In addition, the invention relates to a pharmaceutical combination comprising the first pharmaceutical composition of the invention and a second pharmaceutical composition comprising for example an ADC or a GalNAc-oligonucleotide conjugate. The invention also relates to the first pharmaceutical composition or the pharmaceutical combination of the invention, for use as a medicament, or use in the treatment or prophylaxis of a cancer or an auto-immune disease, a cardiovascular disease or hypercholesterolemia, or in a method for lowering LDL-cholesterol in the circulation of a subject. The invention also relates to a saponin conjugate comprising a (non-)proteinaceous molecule, capable of binding to a cell, and optionally comprising an effector moiety such as an oligonucleotide. The invention also relates to a saponin conjugate comprising GalNAc and an oligonucleotide.

Description

SEMICARBAZONE-BASED SAPONIN CONJUGATE TECHNOLOGICAL FIELD The invention relates to a saponin derivative based on a saponin comprising a triterpene aglycone and at least one saccharide chain linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde functional group which has been transformed to a semicarbazone functional group. The invention also relates to a first pharmaceutical composition comprising the saponin derivative of the invention. In addition, the invention relates to a pharmaceutical combination comprising the first pharmaceutical composition of the invention and a second pharmaceutical composition comprising a conjugate of a cell-surface molecule binding-molecule and an effector moiety, such as any one or more of an antibody-effector moiety conjugate, an receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-nucleic acid conjugate or a receptor-ligand – nucleic acid conjugate (such as a receptor-ligand – oligonucleotide conjugate, wherein for example the oligonucleotide is an AON such as a BNA or an siRNA, and wherein the receptor ligand is for example EGF or at least one GalNAc moiety). The invention also relates to the first pharmaceutical composition or the therapeutic combination comprising the first pharmaceutical composition of the invention, for use as a medicament, or for use in the treatment or prophylaxis of a cancer or an auto-immune disease or a cardiovascular disease or hypercholesterolemia, or for use in a method for decreasing the level of LDL, preferably LDL-cholesterol, in the blood of a subject. Furthermore, the invention relates to an in vitro or ex vivo method for transferring a molecule such as an effector molecule or, when part of a conjugate, an effector moiety, from outside a cell to inside said cell, comprising contacting said cell with the molecule and with a saponin derivative of the invention. The invention also relates to a saponin conjugate comprising a cell-surface molecule binding-molecule such as a proteinaceous molecule or a non-proteinaceous molecule such as a receptor-ligand such as at least one GalNAc moiety, capable of binding to said cell, covalently bound to the saponin, wherein the saponin conjugate is based on the saponin derivative of the invention. The invention also relates to a pharmaceutical combination comprising a third pharmaceutical composition comprising the saponin conjugate of the invention and a fourth pharmaceutical composition comprising an active pharmaceutical ingredient such as a conjugate of a cell-surface molecule binding-molecule and an effector moiety, for example an ADC or an AOC or a conjugate of a receptor ligand, such as at least one GalNAc moiety, and an oligonucleotide, or the invention also relates to a pharmaceutical composition comprising the saponin conjugate of the invention and a conjugate of a cell-surface molecule binding-molecule and an effector moiety such as a conjugate of a receptor ligand, such as at least one GalNAc moiety, and an oligonucleotide. In addition, the invention relates to the pharmaceutical combination of the invention or the pharmaceutical composition of the invention, for use as a medicament, or for use in the treatment or the prophylaxis of a cancer or an auto-immune disease or a cardiovascular disease or hypercholesterolemia, or for use in a method for decreasing the level of LDL-cholesterol in the blood of a subject. The invention also relates to a saponin derivative in which at least one GalNAc moiety, an oligonucleotide and at least one saponin molecule are covalently bound together, wherein the saponin derivative is based on a saponin comprising a triterpene aglycone and at least one saccharide chain linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde functional group which has been transformed to a semicarbazone functional group (also referred to as ‘semicarbazone bond’). An aspect of the invention relates to the saponin derivative encompassing GalNAc, an oligonucleotide and one or more saponin moieties, for use as a medicament or for use in a method for the treatment or prophylaxis of a cardiovascular disease or hypercholesterolemia, or for use in a method for lowering LDL-cholesterol in the blood of a subject. BACKGROUND OF THE INVENTION Targeted tumor therapy is a cancer treatment that uses drugs to target specific genes and proteins that are involved in the growth and survival of cancer cells. Immunotoxins, which are targeted toxins that contain an antibody as targeting moiety, are very promising because they combine the specificity of an antibody against tumor-specific antigens, which enables them to channel the toxin to the aimed point of action and can introduce additionally cell killing mechanisms such as antibody- dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity. To exhibit its effect, the toxin needs to be released into the cytosol after internalization. A major drawback is that the targeting moiety which bears the payload is often not fully internalized, directly recycled to the surface after internalization, or degraded in lysosomes, therewith hampering the sufficient delivery of the payload into the cell cytosol. To ensure a toxic payload concentration for tumor cells and to overcome insufficient cytosolic entry, high serum levels of the targeted toxin are required often resulting in severe side effects, in particular including immunogenicity and vascular leak syndrome. Thus, a sufficiently wide therapeutic window remains a concern when treating cancer patients with antibody-drug conjugates (ADCs). To cope with the drawback of insufficient cytosolic entry, several strategies were developed relating to for example the redirection of toxins to endogenous cellular membrane transport complexes of the biosynthetic pathway, disruption of endosomes, attenuation of the membrane integrity of endosomal membranes, or use of cell penetrating peptides. For example, glycosylated triterpenes such as saponins were found to act as endosomal escape enhancers for targeted toxins, such as ribosome-inactivating proteins (RIPs), in tumor therapy. Structural-activity relationship analysis of saponins revealed that the presence of inter alia an aldehyde at the C-4 position appears to be beneficial for the ability of saponins to enhance the cytotoxicity of RIPs (see Formula (1) with A1 = H or OH and A2 = a polysaccharide moiety).
Figure imgf000004_0001
Formula (1) Especially, saponin SO1861 (Formula (2), sometimes also referred to as SPT001 or SPT1 or SPT), a triterpenoid saponin, was identified as a potent enhancer of the endosomal escape of tumor-cell targeted toxins. A dual effect for the enhancer mechanism is postulated: first, a direct increase of the endosomal escape resulting in caspase-dependent apoptosis that is, second, combined with lysosomal-mediated cell death pathways, which are triggered after the release of cathepsins and other hydrolytic enzymes following destruction of lysosomal membranes.
Figure imgf000004_0002
Formula (2) The application of saponins as endosomal escape enhancers is based on the recognition that these saponins have the ability to rupture erythrocyte membranes. However, at the very same time, the cell rupturing activity of saponins contributes to (the risk for) side effects when a subject is treated with such saponins, therewith influencing optimal therapeutic windows in view of limiting therapeutic index. Indeed, toxicity of such saponins, extracellularly and/or intracellularly, when administered to a patient in need of anti-tumor therapy, is of concern when the optimal dosing regimen and route and frequency of administration are considered. All characteristics of the chemical composition of the saponins themselves, including the structure of the triterpene backbone, a pentacyclic C30 terpene skeleton (also known as sapogenin or aglycone), number and length of saccharide side chains as well as type and linkage variants of the sugar residues linked to the backbone, contribute to the hemolytic potential and/or cytotoxicity of such saponins. The saponins per se are not target-specific when the endosome and the cytosol of cells are considered, and saponins expectedly and most often distribute in a (human) subject with other kinetics than the targeted toxins, even when the same route of administration would be considered for a combination of a saponin and e.g. an ADC. Thus, after application to a patient in need thereof of a therapeutic combination comprising e.g. an ADC and a saponin, the saponin molecules can be found in any organ, implying that specificity is only mediated by the targeted toxin. Distribution of saponins in the whole body (systemic distribution) requires higher concentrations for a successful treatment when compared to specific accumulation in target cells as is achieved for the ADC. Hence, the toxicity of the modified saponins needs to be low enough for a successful application in view of the systemic application of saponins in the body, in order to achieve a suitable therapeutic window. Therefore, there is a still a need to improve the therapeutic index when co-administration of a saponin together with e.g. an ADC is considered: need for better controlling (or better: lowering) the cytotoxicity of saponins while at the same time maintaining sufficient efficacy when potentiation of the cytotoxic effect of an ADC is considered. ADCs are mainly composed of an antibody, a cytotoxic moiety such as a payload, and a linker. Several novel strategies have been proposed and carried out in the design and development of new ADCs to overcome the existing problems, targeting each of the components of ADCs. For example, by identification and validation of adequate antigenic targets for the antibody component, by selecting antigens which have high expression levels in tumor and little or no expression in normal tissues, antigens which are present on the cell surface to be accessible to the circulating ADCs, and antigens which allow internalizing of ADCs into the cell after binding; and alternative mechanisms of activity; design and optimize linkers which enhance the solubility and the drug-to- antibody ratio (DAR) of ADCs and overcome resistance induced by proteins that can transport the chemotherapeutic agent out of the cells; enhance the DAR ratio by inclusion of more payloads, select and optimize antibodies to improve antibody homogeneity and developability. In addition to the technological development of ADCs, new clinical and translational strategies are also being deployed to maximize the therapeutic index, such as, change dosing schedules through fractionated dosing; perform bio-distribution studies; include biomarkers to optimize patient selection, to capture response signals early and monitor the duration and depth of response, and to inform combination studies. An example of ADCs with clinical potential are those ADCs such as brentuximab vedotin, inotuzumab ozogamicin, moxetumomab pasudotox, and polatuzumab vedotin, which are evaluated as a treatment option for lymphoid malignancies and multiple myeloma. Polatuzumab vedotin, binding to CD79b on (malignant) B-cells, and pinatuzumab vedotin, binding to CD22, are tested in clinical trials wherein each ADC was combined with co-administered rituximab, a monoclonal antibody binding to CD20 and not provided with a payload [B. Yu and D. Liu, Antibody-drug conjugates in clinical trials for lymphoid malignancies and multiple myeloma; Journal of Hematology & Oncology (2019) 12:94]. Combinations of monoclonal antibodies such as these examples are yet a further approach and attempt to arrive at the ‘magic bullet’ which combines many or even all of the aforementioned desired characteristics of ADCs. Meanwhile in the past few decades, nucleic acid-based therapeutics have been under development. Therapeutic nucleic acids can be based on deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), in the form of anti-sense oligonucleotides (ASOs, AONs), and short interfering RNAs (siRNAs), microRNAs, and DNA and RNA aptamers, RNA interference (RNAi), and for approaches such as gene therapy. Many of them share the same fundamental basis of action by inhibition of either RNA transcription or driving alternative splicing or degradation of mRNA, thereby preventing expression of disease-related abnormal proteins. The largest number of clinical trials is being carried out in the field of gene therapy, with almost 2600 ongoing or completed clinical trials worldwide but with only about 4% entering phase 3. This is followed by clinical trials with ASOs. Similarl to ADCs, despite the large number of techniques being explored, therapeutic nucleic acids share two major issues during clinical development: delivery into cells and off-target effects (often resulting in intolerable adverse events and side effects). For instance, ASOs such as peptide nucleic acid (PNA), phosphoramidate morpholino oligomer (PMO), locked nucleic acid (LNA) and other bridged nucleic acids (BNA) are being investigated as an attractive strategy to inhibit specifically target genes and especially those genes that are difficult to target with small molecule inhibitors or neutralizing antibodies. Currently, the efficacy of different ASOs is being studied in many neurodegenerative diseases such as Huntington’s disease, Parkinson’s disease, Alzheimer’s disease, and amyotrophic lateral sclerosis but also in several cancer indications. The application of ASOs as potential therapeutic agents requires safe and effective methods for their delivery to the cytoplasm and/or nucleus of the target cells and tissues. Although the clinical relevance of ASOs has been demonstrated, inefficient cellular uptake, both in vitro and in vivo, limit the efficacy of ASOs and has been a barrier to therapeutic development. Cellular uptake can be < 2% of the injected dose, resulting in too low ASO concentration at the active site for an effective and sustained pharmacological activity. This consequently requires an increase of the administered dose which induces off-target effects. Most common side-effects are activation of the complement cascade, the inhibition of the clotting cascade and toll-like receptor mediated stimulation of the immune system. Chemotherapeutics are most commonly small molecules, however, their efficacy is hampered by the severe off-target side toxicity, as well as their poor solubility, rapid clearance and limited tumor exposure. Scaffold-small-molecule drug conjugates such as polymer-drug conjugates (PDCs) are macromolecular constructs with pharmacologically activity, which comprises one or more molecules of a small-molecule drug bound to a carrier scaffold (e.g., polyethylene glycol (PEG)). Such conjugate principle has attracted much attention and has been under investigation for several decades. The majority of conjugates of small-molecule drugs under pre-clinical or clinical development are for oncological indications. However, to this date only one drug not related to cancer has been approved in 2014 (Movantik, a PEG oligomer conjugate of opioid antagonist naloxone, AstraZeneca) for opioid-induced constipation in patients with chronic pain. Translating application of drug-scaffold conjugates into treatment of human subjects provided little clinical success so far. For example, PK1 (N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer doxorubicin; development by Pharmacia, Pfizer) showed great anti-cancer activity in both solid tumors and leukemia in murine models, and was under clinical investigation for oncological indications. Despite demonstrating significant reduction of nonspecific toxicity and improved pharmacokinetics, improvements in anticancer efficacy turned out to be marginal, and as a consequence further development of PK1 was discontinued. The failure of scaffold-small-molecule drug conjugates is at least partially attributed to its poor accumulation at the tumor site. For example, while in murine models PK1 showed 45–250 times higher accumulation in the tumor than in healthy tissues (liver, kidney, lung, spleen, and heart), accumulation in tumor was only observed in a small subset of patients in the clinical trial. A potential solution to these problems is application of nanoparticle systems for drug delivery, such as liposomes. Liposomes are sphere-shaped vesicles consisting of one or more phospholipid bilayers, which are spontaneously formed when phospholipids are dispersed in water. The amphiphilicity characteristics of the phospholipids provide it with the properties of self- assembly, emulsifying and wetting characteristics, and these properties can be employed in the design of new drugs and new drug delivery systems. Drug encapsulated in a liposomal delivery system may convey several advantages over a direct administration of the drug, such as an improvement and control over pharmacokinetics and pharmacodynamics, tissue targeting property, decreased toxicity and enhanced drug activity. Examples of such successes are liposome- encapsulated forms of a small molecule chemotherapy agent doxorubicin (Doxil: a pegylated liposome-encapsulated form of doxorubicin; Myocet: a non-pegylated liposomal doxorubicin), which have been approved for clinical use. Therefore, a solution still needs to be found allowing for drug therapies such as anti-tumor therapies and anti-auto-immune disease therapies (e.g., rheumatoid arthritis treatment options) and, generally, gene-silencing therapies, applicable for non-systemic use when desired, wherein the drug has for example an acceptable safety profile, little to no off-target activity, sufficient efficacy, sufficiently low clearance rate from the patient’s body, a sufficiently wide therapeutic window, etc. SUMMARY OF THE INVENTION According to the inventors the saponin derivatives according to the invention, wherein the aldehyde functional group is transformed to a semicarbazone functional group according to formula (I) are not known in the art.
Figure imgf000008_0004
Here, X = O, P or S, and Y = NR3R4, wherein R3 and R4 independently represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, preferably one of R3 and R4 is H; or
Figure imgf000008_0001
wherein n and m each are an integer independently selected from 1, 2, or 3, Z = CH2, O, S, P or NR5, and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl, an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000008_0002
or an azide moiety according to formula (II)c
Figure imgf000008_0003
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6, and W is a thiol functional group according to formula (III)
Figure imgf000009_0001
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. Surprisingly, the inventors have found that these saponin derivatives have one or more of the following benefits: i) a reduced toxicity when cell viability is considered of cells contacted with the saponin derivatives, ii) increased activity when potentiation of an effector moiety, e.g. toxin cytotoxicity or AON (e.g. BNA) mediated gene silencing, is considered (without wishing to be bound by any theory: relating to similar or improved endosomal escape enhancing activity of the modified saponin) and/or iii) reduced hemolytic activity, when compared with the toxicity, activity and haemolytic activity of unmodified saponin (non- derivatized saponin). Therewith, the inventors provide saponin derivatives with an improved therapeutic window, since the ratio between IC50 values for cell toxicity and e.g. IC50 values for toxin potentiation or IC50 values for gene silencing is increased, and/or since the ratio between IC50 values for saponin haemolytic activity and e.g. IC50 values for toxin potentiation or IC50 values for gene silencing is increased. In addition, the inventors surprisingly established (tumor) cell killing by contacting such cells with a saponin conjugate of the current invention based on a saponin derivative of the current invention e.g. comprising a ligand such as an antibody or a GalNAc moiety, for a cell-surface molecule such as a receptor such as ASGPR (when the ligand is at least one GalNAc moiety in the saponin conjugate), together with an ADC such as an antibody – protein toxin conjugate or a conjugate comprising a GalNAc moiety and an oligonucleotide, despite the medium to low expression of the cell-surface receptor targeted by the cell-surface molecule binding-molecule (e.g. antibody, one or more GalNAc moieties) comprised by the saponin conjugate and/or despite the medium to low expression of the cell-surface receptor targeted by the ADC or by the GalNAc/oligonucleotide conjugate. The saponin derivative and the saponin conjugate of the invention comprise the semicarbazone functional group. For example, in a comparative example, such cell killing when cells are contacted with the ADC could not be established or only to a lower extent, when a saponin conjugate comprising the same cell-surface molecule binding-molecule (e.g., antibody) but comprising a hydrazone functional group (=N-N(H)-C(O)-) instead of the semicarbazone functional group, was contacted with the cells. Therewith, the inventors now provide for a more potent saponin derivative and saponin conjugate, when the activation or potentiating of an effector moiety such as an effector moiety comprised by an ADC or AOC or comprised by a GalNAc/oligonucleotide conjugate, is considered. Preferably, the saponin conjugate of the invention is based on a saponin derivative of the invention and comprising an oligonucleotide, wherein the oligonucleotide comprised by said saponin conjugate is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt. In certain embodiments, the saponin conjugate further comprises a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme), and/or further comprises a non-proteinaceous molecule such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme). Furthermore, the inventors have found that the saponin derivatives according to the invention comprising the semicarbazone functional group hydrolyses more rapidly and in a higher amount towards the corresponding native saponin comprising a “free” aldehyde functional group, as compared to saponin derivatives comprising a hydrazone functional group (=N-N(H)-C(O)-) known in the art, under acidic conditions such as present in endosomes and/or lysosomes of mammalian cells, in particular of human cells. This has the benefit that a lower amount of the saponin derivatives according to the invention should be administered to a patient in need of potentiation of e.g. an ADC or an AOC or a GalNAc/oligonucleotide conjugate, to obtain the same amount of native saponin comprising the “free” aldehyde to act as endosomal escape enhancer for targeted toxins or targeted oligonucleotides, compared to the required amount of saponin derivative comprising the hydrazone functional group (=N-N(H)-C(O)-). Without wishing to be bound by any theory, faster release of the saponin comprising the aldehyde functional group from the saponin derivative that comprises the semicarbazone functional group according to the invention, when compared to release of the saponin comprising the aldehyde functional group from the saponin derivative that comprises the hydrazone functional group, is at the basis for the improved activity of the saponin conjugate of the invention comprising a saponin derivative of the invention, wherein the activity is the potentiation of the effector moiety activity inside the cytosol or nucleus of the targeted cell by endosomal escape enhancement. An aspect of the invention relates to a saponin derivative based on a saponin comprising a triterpene aglycone core structure and at least one of a first saccharide chain ‘R1’ and a second saccharide chain ‘R2’ linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde group, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (I)
Figure imgf000010_0001
wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, X = O, P or S, and Y = NR3R4, wherein R3 and R4 independently represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, preferably one of R3 and R4 is H; or
Figure imgf000011_0002
wherein n and m each are an integer independently selected from 1, 2, or 3, Z = CH2, O, S, P or NR5, and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl, an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000011_0003
or an azide moiety according to formula (II)c
Figure imgf000011_0004
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6, and W is a thiol functional group according to formula (III)
Figure imgf000011_0001
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. Preferred is the saponin derivative according to the invention, wherein the saponin on which the saponin derivative is based is a monodesmosidic or bi-desmosidic triterpene saponin belonging to the type of a 12,13-dehydrooleanane with the aldehyde group in position C-23 and optionally comprising a glucuronic acid group in a carbohydrate substituent at the C-3beta-OH group of the saponin, preferably a bi-desmosidic triterpene saponin belonging to the type of a 12,13- dehydrooleanane with the aldehyde group in position C-23 and comprising a glucuronic acid group in a carbohydrate substituent at the C-3beta-OH group of the saponin. Typically and preferably, the saponin derivative according to the invention is according to formula (IV):
Figure imgf000012_0003
wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, X = O, P or S, and Y = NR3R4, wherein R3 and R4 independently represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, preferably one of R3 and R4 is H; or
Figure imgf000012_0001
, wherein n and m each are an integer independently selected from 1, 2 or 3; Z = CH2, O, S, P or NR5, and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000012_0002
or an azide moiety according to formula (II)c
Figure imgf000013_0001
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6 and W is a thiol functional group according to formula (III)
Figure imgf000013_0002
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. Preferred is the saponin derivative according to the invention, wherein X = O. Also preferred is the saponin derivative according to the invention, wherein
Figure imgf000013_0003
n and m each are an integer independently selected from 1, 2 or 3; and Z = CH2, O, S, P or NR5; and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000013_0004
or an azide moiety according to formula (II)c
Figure imgf000013_0005
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6 and W is a thiol functional group according to formula (III)
Figure imgf000014_0004
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. A saponin derivative according to the invention is a saponin derivative wherein
Figure imgf000014_0005
n and m each are an integer independently selected from 1, 2 or 3; and Z = O or NR5; wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000014_0001
or an azide moiety according to formula (II)c
Figure imgf000014_0002
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6 and W is a thiol functional group according to formula (III)
Figure imgf000014_0003
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. Preferred is the saponin derivative of the invention, wherein
Figure imgf000015_0001
; n and m each are an integer independently selected from 1, 2 or 3; and Z = O or NR5; wherein R5 represents H, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000015_0004
or an azide moiety according to formula (II)c
Figure imgf000015_0002
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6 and W is a thiol functional group according to formula (III)
Figure imgf000015_0003
wherein U = SH, NH2 or OH, preferably NH2 or OH, more preferably OH; and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. Particular (preferred) saponin derivatives according to the invention are saponin derivatives, wherein n = 1 and m = 1, or n = 2 and m = 1, or n = 2 and m = 2, or n = 3 and m = 2, or n = 3 and m = 3; preferably wherein n = 2 and m = 2. An embodiment is the saponin derivative of the invention, wherein the saponin on which the saponin derivative is based is any one or more of: a) saponin selected from any one or more of list A: - Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; - Gypsophila elegans saponin mixture, or a saponin isolated from Gypsophila elegans; - Saponinum album saponin mixture, or a saponin isolated from Saponinum album; - Saponaria officinalis saponin mixture, or a saponin isolated from Saponaria officinalis; and - Quillaja bark saponin mixture, or a saponin isolated from Quillaja bark, for example Quil- A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; or b) a saponin comprising a gypsogenin aglycone core structure, selected from list B: SA1641, gypsoside A, NP-017772, NP-017774, NP-017777, NP-017778, NP-018109, NP- 017888, NP-017889, NP-018108, SO1658 and Phytolaccagenin; or c) a saponin comprising a quillaic acid aglycone core structure, selected from list C: AG1856, AG1, AG2, Agrostemmoside E, GE1741, Gypsophila saponin 1 (Gyp1), NP- 017674, NP-017810, NP-003881, NP-017676, NP-017677, NP-017705, NP-017706, NP- 017773, NP-017775, SA1657, Saponarioside B, SO1542, SO1584, SO1674, SO1700, SO1730, SO1772, 10 SO1832, SO1861, SO1862, SO1904, QS-7, QS-7 api, QS-17, QS- 18, QS-21 A-apio, QS-21 A-xylo, QS-21 B-apio and QS-21 B-xylo; preferably, the saponin is any one or more of a saponin selected list B or C, more preferably, a saponin selected from list C. An embodiment is the saponin derivative of the invention, wherein the saponin (on which the saponin derivative is based) is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS-7, SA1641, a saponin isolated from Saponaria officinalis, Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; preferably wherein the saponin is any one or more of QS- 21, SO1832, SO1861, SA1641 and GE1741; more preferably wherein the saponin is QS-21, SO1832 or SO1861; most preferably being SO1861. An embodiment is the saponin derivative of the invention, wherein the saponin (on which the saponin derivative is based) is a saponin isolated from Saponaria officinalis, preferably wherein the saponin is any one or more of Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; more preferably wherein the saponin is any one or more of SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; even more preferably wherein the saponin is any one or more of SO1832, SO1861 and SO1862; even more preferably wherein the saponin is SO1832 and SO1861; most preferably being SO1861. A saponin derivative according to the invention is the saponin derivative according to molecule (AA):
Figure imgf000017_0001
, wherein
Figure imgf000017_0002
represents a saponin moiety according to formula (SM):
Figure imgf000017_0003
, wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23. Preferably, the saponin derivative of molecule (AA) is based on SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861. A saponin derivative according to the invention is the saponin derivative according to molecule (BB):
Figure imgf000018_0001
, which molecule (BB) is the covalent conjugation product obtained by the covalent conjugation of the saponin derivative according to molecule (AA) with the tri-functional linker according to formula (XXI):
Figure imgf000018_0002
Preferably, the saponin derivative of molecule (BB) is based on SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861. A saponin conjugate according to the invention is the saponin conjugate according to molecule (CC):
Figure imgf000019_0001
, which molecule (CC) is the covalent conjugation product obtained by the covalent conjugation of the tri-functional linker according to formula (XXI) with the saponin derivative according to molecule (AA) and with GalNAc conjugate according to molecule (FF):
Figure imgf000019_0002
, wherein
Figure imgf000019_0003
represents the tri-GalNAc conjugate according to molecule (DD1) or according to molecule (DD2):
Figure imgf000020_0001
wherein y1, y2 and y3 each are an integer independently selected from 0-20, preferably 1-15, more preferably 2-12, even more preferably 2-10, even more preferably 2-8, most preferably 2 and 3, and preferably y1, y2 and y3 are the same, and y4 is an integer selected from 1-100, preferably 2-80, more preferably 3-70, even more preferably 4-60, even more preferably 4-50, even more preferably 4-40, even more preferably 4-30, even more preferably 4-20, even more preferably 4-6, most preferably 3-5, such as 4;
Figure imgf000021_0001
wherein x1, x2 and x3 each are an integer independently selected from 0-20, preferably 1-15, more preferably 2-12, even more preferably 2-10, even more preferably 2-8, most preferably 2 and 3, and preferably x1, x2 and x3 are the same, and x4 is an integer selected from 1-50, preferably 2-40, more preferably 3-30, even more preferably 4-20, even more preferably 5-15, most preferably 8- 12, such as 9, and preferably represents the tri-GalNAc conjugate according to molecule (DD3) or according to molecule (DD4):
Figure imgf000022_0001
Preferably, the saponin conjugate of molecule (CC) is based on saponin SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861. A saponin conjugate according to the invention is the saponin conjugate according to molecule (EE):
Figure imgf000023_0001
, which molecule (EE) is the covalent conjugation product obtained by the covalent conjugation of the tri-functional linker according to formula (XXI) with the saponin derivative according to molecule (AA) and with GalNAc conjugate according to molecule (FF) and with the oligonucleotide provided with a linker according to molecule (GG):
Figure imgf000023_0002
, wherein the molecule (GG) represents the conjugation product of the conjugation reaction between the linker (E)-1-(4-((2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)hexanoyl)hydrazineylidene)methyl)benzamido)-N-(4-(6-methyl-1,2,4,5-tetrazin-3-yl)benzyl)- 3,6,9,12-tetraoxapentadecan-15-amide and the oligonucleotide-linker molecule according to molecule (HH):
Figure imgf000024_0002
Preferably, the saponin conjugate of molecule (EE) is based on saponin SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861. Typically, the oligonucleotide of molecule (EE) is an AON such as a BNA or an siRNA. For example, the oligonucleotide of molecule (EE) is a BNA, for example a BNA for silencing HSP27 expression or apoB expression, preferably in a human cell. A saponin derivative according to the invention is the saponin derivative according to molecule (JJ):
Figure imgf000024_0001
which molecule (JJ) is the conjugate product of conjugation of N,N'-((9S,19S)-14-(6- aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo-4,11,14,17- tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide first with saponin derivative according to molecule (KK):
Figure imgf000025_0001
and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate , wherein
Figure imgf000025_0002
represents a saponin moiety according to formula (SM). Preferably, the saponin derivative of molecule (JJ) is based on SO1861, SO1832 or QS- 21, more preferably SO1861 or SO1832, most preferably SO1861. A saponin conjugate according to the invention is the saponin conjugate according to molecule (LL):
Figure imgf000026_0001
, which molecule (LL) is the covalent conjugation product obtained by the covalent conjugation of the molecule (JJ) with the conjugate of the tri-functional linker and GalNAc according to molecule (MM):
Figure imgf000027_0001
, wherein molecule (MM) is the conjugate of the tri-functional linker according to formula (XXI) and the GalNAc conjugate according to molecule (NN):
Figure imgf000027_0002
, wherein
Figure imgf000027_0003
represents the tri-GalNAc conjugate according to molecule (DD1) or molecule (DD2), preferably molecule (DD3) or molecule (DD4), more preferably molecule (DD3) as detailed here above. A saponin conjugate according to the invention is the saponin conjugate according to molecule (PP): edi toe lcunogi l o
Figure imgf000028_0001
, which molecule (PP) is the covalent conjugation product obtained by the covalent conjugation of the molecule (LL) with the oligonucleotide provided with a linker according to molecule (GG). A saponin derivative according to the invention is the saponin derivative according to molecule (QQ):
Figure imgf000029_0001
, which molecule (QQ) is the conjugate product of conjugation of (2S)-N-[(1S)-1-{[2-(6-amino-N-{2- [(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate first with saponin derivative according to molecule (KK) and subsequently with 2,5- dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate. Preferably, the saponin derivative of molecule (QQ) is based on SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861. A saponin conjugate according to the invention is the saponin conjugate according to molecule (RR):
Figure imgf000030_0001
, which molecule (RR) is the covalent conjugation product obtained by the covalent conjugation of the molecule (QQ) with the conjugate of the tri-functional linker and GalNAc according to molecule (MM). A saponin conjugate according to the invention is the saponin conjugate according to molecule (SS):
Figure imgf000031_0001
(SS) , which molecule (SS) is the covalent conjugation product obtained by the covalent conjugation of the molecule (RR) with the oligonucleotide provided with a linker according to molecule (GG). Preferably, the saponin derivatives of molecule (JJ) and molecule (QQ) and/or the saponin conjugates of molecules (LL), (PP), (RR) and/or (SS) is/are based on saponin SO1861, SO1832 or QS-21, more preferably SO1861 or SO1832, most preferably SO1861. Typically, the oligonucleotide of molecule (PP) and/or of molecule (SS) is/are an AON such as a BNA or an siRNA. For example, the oligonucleotide of molecule (SS) is a BNA, for example a BNA for silencing HSP27 expression or apoB expression, preferably in a human cell. An aspect of the invention relates to a ninth pharmaceutical composition comprising any one of the conjugates according to molecules (LL), (PP), (RR) and (SS). An aspect of the invention relates to the ninth pharmaceutical composition comprising any one of the conjugates according to molecules (LL), (PP), (RR) and (SS) or to any one of the conjugates according to molecules (LL), (PP), (RR) and (SS), for use as a medicament. An aspect of the invention relates to the ninth pharmaceutical composition comprising any one of the conjugates according molecules (LL), (PP), (RR) and (SS) or to any one of the conjugates according to molecules (LL), (PP), (RR) and (SS), for use in the treatment or prophylaxis of a cancer, an infectious disease, a viral infection, hypercholesterolemia, cardiovascular disease, primary hyperoxaluria, haemophilia A, haemophilia B, AAT related liver disease, acute hepatic porphyria, TTR-mediated amyloidosis, hereditary TTR amyloidosis (hATTR), complement- mediated disease, hepatitis B infection, hepatitis C infection, α1-antitrypsin deficiency, β- thalassaemia, or an auto-immune disease. An aspect of the invention relates to the ninth pharmaceutical composition comprising any one of the conjugates according to molecules (LL), (PP), (RR) and (SS) or to any one of the conjugates according to molecules (LL), (PP), (RR) and (SS), for use in the lowering of LDL- cholesterol in a subject. In preferred saponin derivatives according to the invention and/or preferred saponin conjugates of the invention R1 is selected from: H, GlcA-, Glc-, Gal-, Rha-(1→2)-Ara-, Gal-(1→2)-[Xyl-(1→3)]-GlcA-, Glc-(1→2)-[Glc-(1→4)]-GlcA-, Glc-(1→2)-Ara-(1→3)-[Gal-(1→2)]-GlcA-, Xyl-(1→2)-Ara-(1→3)-[Gal-(1→2)]-GlcA-, Glc-(1→3)-Gal-(1→2)-[Xyl-(1→3)]-Glc-(1→4)-Gal-, Rha-(1→2)-Gal-(1→3)-[Glc-(1→2)]-GlcA-, Ara-(1→4)-Rha-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Rha-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Rha-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Ara-(1→4)-Rha-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, and derivatives thereof, and R2 is selected from: H, Glc-, Gal-, Rha-(1→2)-[Xyl-(1→4)]-Rha-, Rha-(1→2)-[Ara-(1→3)-Xyl-(1→4)]-Rha-, Ara-, Xyl-, Xyl-(1→4)-Rha-(1→2)-[R1-(→4)]-Fuc- wherein R1 is 4E-Methoxycinnamic acid, Xyl-(1→4)-Rha-(1→2)-[R2-(→4)]-Fuc- wherein R2 is 4Z-Methoxycinnamic acid, Xyl-(1→4)-[Gal-(1→3)]-Rha-(1→2)-4-OAc-Fuc-, Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-3,4-di-OAc-Fuc-, Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R6-(→4)]-3-OAc-Fuc- wherein R6 is 4E-Methoxycinnamic acid, Glc-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-4-OAc-Fuc-, Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-4-OAc-Fuc-, (Ara- or Xyl-)(1→3)-(Ara- or Xyl-)(1→4)-(Rha- or Fuc-)(1→2)-[4-OAc-(Rha- or Fuc-)(1→4)]-(Rha- or Fuc-), Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Qui-(1→4)]-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-Fuc-, Xyl-(1→4)-[Gal-(1→3)]-Rha-(1→2)-Fuc-, Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-Fuc-, Ara/Xyl-(1→4)-Rha/Fuc-(1→4)-[Glc/Gal-(1→2)]-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R7-(→4)]-Fuc- wherein R7 is 5-O-[5-O-Ara/Api-3,5- dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R8-(→4)]-Fuc- wherein R8 is 5-O-[5-O-Ara/Api-3,5-dihydroxy-6- methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Rha-(1→3)]-4-OAc-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[Rha-(1→3)]-4-OAc-Fuc-, 6-OAc-Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3-OAc-Rha-(1→3)]-Fuc-, Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3-OAc--Rha-(1→3)]-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Qui-(1→4)]-Fuc-, Glc-(1→3)-[Xyl-(1→4)]-Rha-(1→2)-[Qui-(1→4)]-Fuc-, Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3,4-di-OAc-Qui-(1→4)]-Fuc-, Glc-(1→3)-[Xyl-(1→4)]-Rha-(1→2)-Fuc-, 6-OAc-Glc-(1→3)-[Xyl-(1→4)]-Rha-(1→2)-Fuc-, Glc-(1→3)-[Xyl-(1→3)-Xyl-(1→4)]-Rha-(1→2)-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[Rha-(1→3)]-4OAc-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[Rha-(1→3)]-4OAc-Fuc-, Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R9-(→4)]-Fuc- wherein R9 is 5-O-[5-O-Rha- (1→2)-Ara/Api-3,5-dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R10-(→4)]-Fuc- wherein R10 is 5-O-[5-O- Ara/Api-3,5-dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R11-(→4)]-Fuc- wherein R11 is 5-O-[5-O- Ara/Api-3,5-dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R12-(→4)]-Fuc- wherein R12 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R13-(→4)]-Fuc- wherein R13 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R14-(→3)]-Fuc- wherein R14 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R15-(→3)]-Fuc- wherein R15 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid) Glc-(1→3)-[Glc-(1→6)]-Gal-, and derivatives thereof. In preferred saponin derivatives according to the invention and/or preferred saponin conjugates of the invention, R1 is Gal-(1→2)-[Xyl-(1→3)]-GlcA-; and R2 is selected from: Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3,4-di-OAc-Qui-(1→4)]-Fuc-, Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R12-(→4)]-Fuc- wherein R12 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R13-(→4)]-Fuc- wherein R13 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R14-(→3)]-Fuc- wherein R14 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, and Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R15-(→3)]-Fuc- wherein R15 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, preferably, R1 is Gal-(1→2)-[Xyl-(1→3)]-GlcA- and R2 is Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl- (1→3)-4-OAc-Qui-(1→4)]-Fuc-. Typically, for the saponin derivative according to the invention, the saponin derivative is a derivative of a saponin selected from the group of saponins consisting of: Quillaja bark saponin, dipsacoside B, saikosaponin A, saikosaponin D, macranthoidin A, esculentoside A, phytolaccagenin, aescinate, AS6.2, NP-005236, AMA-1, AMR, alpha-Hederin, NP-012672, NP- 017777, NP-017778, NP-017774, NP-018110, NP-017772, NP-018109, NP-017888, NP-017889, NP-018108, SA1641, AE X55, NP-017674, NP-017810, AG1, NP-003881, NP-017676, NP- 017677, NP-017706, NP-017705, NP-017773, NP-017775, SA1657, AG2, SO1861, GE1741, SO1542, SO1584, SO1658, SO1674, SO1832, SO1904, SO1862, QS-7, QS1861, QS-7 api, QS1862, QS-17, QS-18, QS-21 A-apio, QS-21 A-xylo, QS-21 B-apio, QS-21 B-xylo, beta-Aescin, Aescin Ia, Teaseed saponin I, Teaseedsaponin J, Assamsaponin F, Digitonin, Primula acid 1 and AS64R, preferably the saponin derivative is selected from the group consisting of a QS-21 derivative, an SO1861 derivative, an SA1641 derivative and a GE1741 derivative, more preferably the saponin derivative is selected from the group consisting of a QS-21 derivative and an SO1861 derivative, most preferably the saponin derivative is an SO1861 derivative. Also preferred is the saponin derivative according to the invention, which is a derivative of SO1861, SO1832 or QS-21, preferably SO1861 and SO1832. Particularly preferred is a saponin derivative of the invention, wherein the saponin derivative is according to formula (V), formula (VI), formula (VII) or formula (VIII):
Figure imgf000035_0001
Figure imgf000036_0001
preferably wherein the saponin derivative is according to formula (V), formula (VII) or formula (VIII), more preferably wherein the saponin derivative is according to formula (V) or formula (VIII), most preferably according to formula (VIII). Preferred is a saponin derivative of the invention, wherein the saponin derivative is according to molecule (V), molecule (VII) or molecule (VIII):
5
Figure imgf000037_0001
Figure imgf000038_0001
Molecule (VIII). An aspect of the invention relates to a first pharmaceutical composition comprising the saponin derivative according to the invention and optionally a pharmaceutically acceptable excipient and/or diluent. An aspect of the invention relates to a first pharmaceutical combination comprising: (a) the first pharmaceutical composition of the invention; and (b) a second pharmaceutical composition comprising a conjugate of a cell-surface molecule binding-molecule and an effector moiety, wherein the cell-surface molecule binding-molecule is a proteinaceous molecule such as an antibody, and optionally comprising a pharmaceutically acceptable excipient and/or diluent. An aspect of the invention relates to a first pharmaceutical combination comprising: (a) the first pharmaceutical composition of the invention; and (b) a second pharmaceutical composition comprising any one or more of: a conjugate of a cell- surface molecule binding-molecule and an effector moiety, an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-oligonucleotide conjugate, and a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent. An aspect of the invention relates to a third pharmaceutical composition comprising the saponin derivative of the invention and further comprising a conjugate of a cell-surface molecule binding- molecule and an effector moiety, wherein the cell-surface molecule binding-molecule is a proteinaceous molecule such as an antibody, and optionally comprising a pharmaceutically acceptable excipient and/or diluent. An aspect of the invention relates to a third pharmaceutical composition comprising the saponin derivative of the invention and further comprising any one or more of: a conjugate of a cell-surface molecule binding-molecule and an effector moiety, an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody- oligonucleotide conjugate and a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent. An embodiment is the first pharmaceutical combination comprising the second pharmaceutical composition of the invention, or the third pharmaceutical composition of the invention, wherein the second pharmaceutical composition or the third pharmaceutical composition comprises any one or more of an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody- oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, wherein preferably the toxin is a protein toxin. Preferred is the first pharmaceutical combination comprising the first pharmaceutical composition of the invention, or the third pharmaceutical composition of the invention, wherein the saponin derivative is any one or more of the saponin derivatives according to the invention. An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use as a medicament. An aspect of the invention relates to the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use as a medicament. An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cancer or an auto-immune disease. An aspect of the invention relates to the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cancer or an auto-immune disease. An aspect of the invention relates to the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cardiovascular disease or of hypercholesterolemia, or for use in a method for lowering LDL-cholesterol in the blood of a subject, preferably a human subject. Examples of suitable target cell-surface receptors to which the saponin conjugate of the invention can bind are: HER2, EGFR and CD71. Therefore, these targets are preferred. More preferred is CD71. An aspect of the invention relates to the first pharmaceutical combination of the invention, the second pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, or to the 1-component saponin conjugate of the invention, for use according to the invention, i.e., for use in the treatment or prevention of a disease or health problem related to presence of a diseased cell according to the invention, for use in the treatment or prevention of a disease or health problem related to the presence of the aberrant cell according to the invention, for use in the treatment or prevention of a cancer, and/or for use in the treatment or prevention of an autoimmune disease, preferably in a human patient, wherein the first cell surface molecule and the third cell surface molecule are CD71 and/or the second cell surface molecule is CD71, and/or the first proteinaceous molecule and the third proteinaceous molecule are a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the second proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the effector moiety is an oligonucleotide, preferably, the first, second and third cell surface molecule is CD71, the first, second and third proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and the effector moiety is an oligonucleotide. An aspect of the invention relates to an in vitro or ex vivo method for transferring a molecule from outside a cell to inside said cell, preferably into the cytosol of said cell, comprising the steps of: a) providing a cell; b) providing the molecule for transferring from outside the cell into the cell provided in step a); c) providing a saponin derivative according to the invention; d) contacting the cell of step a) in vitro or ex vivo with the molecule of step b) and the saponin derivative of step c), therewith establishing the transfer of the molecule from outside the cell into said cell. An aspect of the invention relates to a saponin conjugate based on a saponin derivative according to the invention, wherein the aldehyde group (of the saponin) is transformed into a semicarbazone functional group according to formula (IX)
Figure imgf000040_0001
wherein n and m each are an integer independently selected from 1, 2, or 3; o is an integer selected from 0-10, preferably 2-7, more preferably 4-6; and wherein the maleimide functional group is further transformed into a thioether bond through reaction with a first proteinaceous molecule (‘proteinaceous molecule 1’) comprising a thiol functional group according to formula (X)
Figure imgf000041_0001
A preferred saponin conjugate according to the invention is the saponin conjugate according to formula (XI)
Figure imgf000041_0002
wherein R1 and R2 are as defined in any one of claims 1-10; n and m each are an integer independently selected from 1, 2 or 3; and o is an integer selected from 0-10, preferably 2-7, more preferably 4-6. A typical (preferred) saponin conjugate according to the invention is a saponin conjugate, wherein n = 1 and m = 1, or n = 2 and m = 1, or n = 2 and m = 2, or n = 3 and m = 2, or n = 3 and m = 3; preferably wherein n = 2 and m = 2. Preferred is the saponin conjugate according to the invention, wherein the saponin conjugate is according to formula (XII)
Figure imgf000042_0001
Also part of the invention is the saponin conjugate according to the invention, wherein the proteinaceous molecule 1 comprises a covalently bound effector moiety. Preferred is the saponin conjugate according to the invention, wherein the effector moiety is an oligonucleotide. Thus, in certain embodiments the saponin conjugate comprises the proteinaceous molecule 1 and an oligonucleotide. Preferred is the saponin conjugate of the invention based on a saponin derivative of the invention and comprising an oligonucleotide, wherein the oligonucleotide comprised by said saponin conjugate is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt. In certain embodiments, the saponin conjugate further comprises a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme), and/or further comprises a non-proteinaceous molecule such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme). Preferred is the saponin conjugate of the invention based on a saponin derivative of the invention, wherein the proteinaceous molecule 1 comprised by the saponin conjugate is covalently bound to an oligonucleotide, wherein preferably the oligonucleotide is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt. An aspect of the invention relates to an eighth pharmaceutical composition comprising the saponin conjugate which comprises the proteinaceous molecule 1 comprising a covalently bound effector moiety, preferably an oligonucleotide, and optionally a pharmaceutically acceptable excipient and/or diluent. An aspect of the invention relates to the eighth pharmaceutical composition for use as a medicament. Preferably, in the saponin conjugate according to the invention, the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule. A typical saponin conjugate of the invention is the saponin conjugate, wherein the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule, wherein said first binding site is or comprises any one or more of: an amino acid, a peptide, a protein, an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, a ligand for a cell-surface molecule such as a receptor such as EGF or a cytokine. The antibodies (immunoglobulins) of the present invention may be bi- or multifunctional. For example, a bifunctional antibody has one arm having a specificity for one receptor or antigen, while the other arm recognizes a different receptor or antigen. Alternatively, each arm of the bifunctional antibody may have specificity for a different epitope of the same receptor or antigen of the target cell. The antibodies (immunoglobulins) of the present invention may be, but are not limited to, polyclonal antibodies, monoclonal antibodies, human antibodies, humanized antibodies, chimeric antibodies, resurfaced antibodies, anti-idiotypic antibodies, mouse antibodies, rat antibodies, rat/mouse hybrid antibodies, llama antibodies, llama heavy-chain only antibodies, heavy-chain only antibodies, and veterinary antibodies. Preferably, the antibody (immunoglobulin) of the present invention is a monoclonal antibody. The resurfaced, chimeric, humanized and fully human antibodies are also more preferred because they are less likely to cause immunogenicity in humans. The antibodies of the ADC of the present invention preferably specifically binds to an antigen expressed on the surface of a cancer cell, an autoimmune cell, a diseased cell, an aberrant cell, while leaving any healthy cell essentially unaltered (e.g., by not binding to such normal cell, or by binding to a lesser extent in number and/or affinity to such healthy cell). A preferred embodiment is the saponin conjugate according to the invention, wherein the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule, wherein said first binding site is or comprises any one or more of: a single-domain antibody (sdAb), preferably a VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VHH domain such as derived from a heavy-chain only antibody (HCAb) such as from Camelidae origin or Ig-NAR origin such as a variable heavy chain new antigen receptor (VNAR) domain, preferably the HCAb is from Camelidae origin, preferably the sdAb is a VHH domain derived from an HCAb from Camelidae origin (camelid VH) such as derived from an HCAb from camel, lama, alpaca, dromedary, vicuna, guanaco and Bactrian camel. Preferably, in the saponin conjugate according to the invention, the first epitope of the first cell-surface molecule, to which the proteinaceous molecule 1 can preferably bind, is a tumor-cell specific first epitope of a first tumor-cell surface molecule, more preferably a tumor-cell specific first epitope of a first tumor-cell surface receptor specifically present on a tumor cell. An embodiment is the saponin conjugate of the invention, based on the saponin derivative of the invention, wherein the first cell surface molecule is a first cell surface receptor, preferably an endocytic cell-surface receptor, preferably a diseased cell specific receptor or an aberrant cell specific receptor or a tumor-cell specific receptor, or a receptor overexpressed at a diseased cell, aberrant cell or tumor cell, more preferably the cell surface molecule is selected from any one or more of: CD71, CA125, EpCAM(17-1A), CD52, CEA, CD44v6, FAP, EGF-IR, integrin, syndecan-1, vascular integrin alpha-V beta-3, HER2, EGFR, CD20, CD22, Folate receptor 1, CD146, CD56, CD19, CD138, CD27L receptor, prostate specific membrane antigen (PSMA), CanAg, integrin- alphaV, CA6, CD33, mesothelin, Cripto, CD3, CD30, CD239, CD70, CD123, CD352, DLL3, CD25, ephrinA4, MUC-1, Trop2, CEACAM5, CEACAM6, HER3, CD74, PTK7, Notch3, FGF2, C4.4A, FLT3, CD38, FGFR3, CD7, PD-L1, CTLA-4, CD52, PDGFRA, VEGFR1, VEGFR2, c-Met (HGFR), EGFR1, RANKL, ADAMTS5, CD16, CXCR7 (ACKR3), glucocorticoid-induced TNFR-related protein (GITR), even more preferably the cell surface molecule is selected from: CD71, HER2, c- Met, VEGFR2, CXCR7, CD71, EGFR and EGFR1, even more preferably the cell surface molecule is any one of CD71, HER2 and EGFR, most preferably the cell surface molecule is cell surface receptor CD71. An embodiment is the saponin conjugate of the invention, comprising an antibody, based on the saponin derivative of the invention, wherein the antibody is selected from, or the sdAb is derived from or based on, any one or more of immunoglobulins: an anti-CD71 antibody such as IgG type OKT-9, an anti-HER2 antibody such as trastuzumab (Herceptin), pertuzumab, an anti-CD20 antibody such as rituximab, ofatumumab, tositumomab, obinutuzumab ibritumomab, an anti-CA125 antibody such as oregovomab, an anti-EpCAM (17-1A) antibody such as edrecolomab, an anti- EGFR antibody such as cetuximab, matuzumab, panitumumab, nimotuzumab, an anti-CD30 antibody such as brentuximab, an anti-CD33 antibody such as gemtuzumab, huMy9-6, an anti- vascular integrin alpha-v beta-3 antibody such as etaracizumab, an anti-CD52 antibody such as alemtuzumab, an anti-CD22 antibody such as epratuzumab, pinatuzumab, binding fragment (Fv) of anti-CD22 antibody moxetumomab, humanized monoclonal antibody inotuzumab, an anti-CEA antibody such as labetuzumab, an anti-CD44v6 antibody such as bivatuzumab, an anti-FAP antibody such as sibrotuzumab, an anti-CD19 antibody such as huB4, an anti-CanAg antibody such as huC242, an anti-CD56 antibody such as huN901, an anti-CD38 antibody such as daratumumab, OKT-10 anti-CD38 monoclonal antibody, an anti-CA6 antibody such as DS6, an anti-IGF-1R antibody such as cixutumumab, 3B7, an anti-integrin antibody such as CNTO 95, an anti-syndecan- 1 antibody such as B-B4, an anti-CD79b such as polatuzumab, an anti-HIVgp41 antibody, or an immunoglobulin with at least 95% amino-acid sequence identity with any one of these immunoglobulins, preferably at least 96%, more preferably at least 97%, even more preferably at least 98%, even more preferably at least 99%, preferably the antibody is selected from, or the sdAb is derived from or based on any one or more of immunoglobulins: an anti-HIVgp41 antibody, an anti-CD71 antibody, an anti-HER2 antibody and an anti-EGFR antibody, or an immunoglobulin with at least 95% amino-acid sequence identity with any one of these immunoglobulins, preferably at least 96%, more preferably at least 97%, even more preferably at least 98%, even more preferably at least 99%, more preferably the antibody is, or the sdAb is derived from or based on any one or more of: trastuzumab, pertuzumab, cetuximab, matuzumab, an anti-CD71 antibody, OKT-9, or an immunoglobulin with at least 95% amino-acid sequence identity with any one of these immunoglobulins, preferably at least 96%, more preferably at least 97%, even more preferably at least 98%, even more preferably at least 99%, even more preferably the antibody is, or the sdAb is derived from or based on any one or more of: an anti-CD71 antibody, trastuzumab, cetuximab, the anti-CD71 antibody OKT-9, or an immunoglobulin with at least 95% amino-acid sequence identity with any one of these immunoglobulins, preferably at least 96%, more preferably at least 97%, even more preferably at least 98%, even more preferably at least 99%, more preferably the antibody is, or the sdAb is derived from or based on any one or more of: an anti-CD71 antibody such as OKT-9, or an immunoglobulin with at least 95% amino-acid sequence identity with such immunoglobulin, preferably at least 96%, more preferably at least 97%, even more preferably at least 98%, even more preferably at least 99%, and preferably the proteinaceous molecule 1 is a monoclonal antibody, preferably an anti-CD71-antibody. It is specifically preferred that for the saponin derivative according to the invention and/or the saponin conjugate according to the invention, the semicarbazone functional group
Figure imgf000045_0001
is hydrolysable (cleavable) under acidic conditions, preferably at pH 4.0 – 6.5, wherein hydrolysis of said semicarbazone functional group provides the aldehyde group on the aglycone core structure of the saponin on which the saponin derivative is based. Thus, a specifically preferred embodiment is the saponin derivative according to the invention and/or the saponin conjugate according to the invention, wherein the semicarbazone functional group is subject to hydrolysis in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ≤ 5.5. Surprisingly, the inventors have found that the saponin derivatives according to the invention which are used as a component for potentiating the intracellular effect of an effector molecule or effector moiety when the effector molecule is provided as a conjugate comprising a cell-surface molecule binding-molecule such as an antibody, e.g. as an ADC or AOC, are now also suitably for (covalent) coupling to a cell-surface molecule binding-molecule such as a cell-surface molecule targeting antibody, such as an sdAb, such that by such coupling the saponin conjugate of the invention is provided, endowed with, for example, anti-tumor activity potentiating activity when used in combination with for example an ADC or an AOC. An aspect of the invention relates to a second pharmaceutical combination comprising: (a) a fourth pharmaceutical composition comprising the saponin conjugate of the invention and optionally a pharmaceutically acceptable excipient and/or diluent; and (b) a fifth pharmaceutical composition comprising a conjugate comprising a cell- surface molecule binding-molecule, such as a second proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety, wherein the proteinaceous molecule 2 is the same or different from the proteinaceous molecule 1 present in the saponin conjugate, and if the proteinaceous molecule 2 is different from the proteinaceous molecule 1, the proteinaceous molecule 2 comprising a second binding site for binding to a second epitope of a second cell-surface molecule, wherein the second cell-surface molecule is the same as or different from the first cell surface molecule, and if the second cell-surface molecule is different from the first cell surface molecule, the second cell-surface molecule and the first cell surface molecule are preferably present on the same cell, the fifth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent. The effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based. The effector moiety is not the saponin derivative or the saponin conjugate of the invention. An embodiment is the second pharmaceutical combination of the invention, comprising: (a) the fourth pharmaceutical composition of the invention comprising the saponin conjugate of the invention, wherein the first epitope on the first cell-surface molecule is a tumor-cell specific first epitope on a first tumor cell-specific surface molecule, preferably a tumor-cell specific first epitope on a first cell-surface receptor specifically present at a tumor cell; and (b) the fifth pharmaceutical composition of the invention, wherein the second cell-surface molecule is a second tumor cell-specific surface molecule which is the same or different from the first tumor cell-specific surface molecule, preferably a second cell-surface receptor specifically present at a tumor cell which is the same or different from the first cell-surface receptor specifically present at said tumor cell, and wherein the second epitope is a tumor-cell specific second epitope, wherein the first epitope and the second epitope, which is the same as or different from the first epitope, are exposed at the same cell. An aspect of the invention relates to a third pharmaceutical combination, comprising: (a) the fourth pharmaceutical composition of the invention comprising the saponin conjugate according to the invention, comprising the first binding site for binding to the first epitope on the first cell-surface molecule, the fourth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent; and (b) a sixth pharmaceutical composition comprising a conjugate comprising a cell-surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, wherein the proteinaceous molecule 3 comprises the first binding site for binding to the first epitope on the cell-surface molecule of (a), the sixth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent, wherein the first binding site of the proteinaceous molecule 1 and the first binding site of the proteinaceous molecule 3 are the same, and wherein the first cell-surface molecule and the first epitope on the first cell-surface molecule, to which the proteinaceous molecule 1 can bind, and the first cell-surface molecule and the first epitope on the first cell-surface molecule, to which the proteinaceous molecule 3 can bind, are the same. The effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based. The effector moiety is not the saponin derivative or the saponin conjugate of the invention. An aspect of the invention relates to a third pharmaceutical combination, comprising: (a) the fourth pharmaceutical composition of the invention and (b) the sixth pharmaceutical composition of the invention, wherein the first cell-surface molecule is expressed on a tumor cell surface, and preferably the first cell-surface molecule is a tumor cell-specific surface molecule, and wherein preferably the first epitope is a first tumor-cell specific epitope. Preferred are the second pharmaceutical combination or third pharmaceutical combination according to the invention, wherein the second binding site of the proteinaceous molecule 2 and/or the third binding site of the proteinaceous molecule 3 comprises or consists of an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, single-domain antibody (sdAb), scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a ligand for a cell-surface molecule such as a receptor such as EGF and a cytokine, a single-domain antibody (sdAb), preferably VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VHH domain such as derived from a heavy-chain only antibody (HCAb) such as from Camelidae origin or Ig-NAR origin such as a variable heavy chain new antigen receptor (VNAR) domain, preferably the HCAb is from Camelidae origin, preferably the sdAb is a VHH domain derived from an HCAb from Camelidae origin (camelid VH) such as derived from an HCAb from camel, lama, alpaca, dromedary, vicuna, guanaco and Bactrian camel. An aspect of the invention relates to a seventh pharmaceutical composition comprising: (a) the saponin conjugate of the invention; and (b) the conjugate comprising proteinaceous molecule 2 and an effector moiety of the invention, or the conjugate comprising proteinaceous molecule 3 and an effector moiety of the invention, and optionally further comprising a pharmaceutically acceptable excipient and/or diluent. The effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based. The effector moiety is not the saponin derivative or the saponin conjugate of the invention. An aspect of the invention relates to the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, for use as a medicament. An aspect of the invention relates to the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, for use in the treatment or prevention of a cancer or of an autoimmune disease such as rheumatoid arthritis. A preferred embodiment is the first pharmaceutical combination of the invention, or the second pharmaceutical combination of the invention, or third pharmaceutical composition of the invention, for use according to the invention, preferably in a human patient, wherein the first cell surface molecule and the third cell surface molecule are CD71 and/or the second cell surface molecule is CD71, and/or the first proteinaceous molecule and the third proteinaceous molecule are a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the second proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the effector moiety is an oligonucleotide, preferably, the first, second and third cell surface molecule is CD71, the first, second and third proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and the effector moiety is an oligonucleotide. An embodiment is the saponin derivative of the invention, or the saponin conjugate of the invention, wherein the saponin on which the saponin derivative is based or on which the saponin conjugate is based, is isolated from a plant. Preferably, the saponin is isolated from a part of a plant, such as the root, or from a part of a tree, such as the bark. Preferably, the saponin is isolated from roots derived from a plant. DEFINITIONS The term “saponin“ has its regular scientific meaning and here refers to a group of amphipatic glycosides which comprise one or more hydrophilic glycone moieties combined with a lipophilic aglycone core which is a sapogenin. The saponin may be naturally-occurring or synthetic (i.e., non- naturally occurring). The term “saponin” includes naturally-occurring saponins, derivatives of naturally-occurring saponins as well as saponins synthesized de novo through chemical and/or biotechnological synthesis routes. The term “cell-surface molecule” has its regular scientific meaning and here refers to a molecule that is present and exposed at the outside surface of a cell such as a blood cell or an organ cell, such as a mammalian cell, such as a human cell. The term “saponin derivative” has its regular scientific meaning and here refers to a saponin, i.e. a modified saponin, which has a chemical modification at a position where previously an aldehyde group was present in the non-derivatised saponin before being subjected to chemical modification for provision of the saponin derivative. For example, the saponin derivative is provided by chemical modification of an aldehyde group, in a saponin upon which the saponin derivative is based, i.e. the saponin is provided and an aldehyde group is chemically modified therewith providing the saponin derivative. For example, the saponin that is derivatised for provision of the saponin derivative is a naturally occurring saponin. Typically, the saponin derivative is a synthetic saponin, typically the saponin derivative is a derivatisation of a natural saponin, and is thus derived from a natural saponin, although a saponin derivative can also be derived from a synthetic saponin which may or may not have a natural counterpart. Typically, the saponin derivative has not a natural counterpart, i.e. the saponin derivative is not produced naturally by e.g. plants or trees. Optionally, the saponin derivative further has one or more chemical modifications at positions where previously any of a carboxyl group, an acetate group and/or an acetyl group was present in the non-derivatised or derivatised saponin before being subjected to chemical modification for provision of the saponin derivative. For example, the saponin derivative is provided by chemical modification of any one or more of a carboxyl group, an acetate group and/or an acetyl group in a saponin upon which the saponin derivative is based, i.e. the saponin is provided and an aldehyde group, a carboxyl group, an acetate group and/or an acetyl group is chemically modified therewith providing the saponin derivative. The term “mono-desmosidic saponin” has its regular scientific meaning and here refers to a triterpenoid saponin containing a single saccharide chain bound to the aglycone core, wherein the saccharide chain consists of one or more saccharide moieties. The term “bi-desmosidic saponin” has its regular scientific meaning and here refers to a triterpenoid saponin containing two saccharide chains bound to the aglycone core, wherein each of the two saccharide chains consists of one or more saccharide moieties. The term “triterpenoid saponin” has its regular scientific meaning and here refers to a saponin having a triterpenoid-type of aglycone core structure. The triterpenoid saponin differs from a saponin based on a steroid glycoside such as sapogenol in that such saponin comprising steroid glycoside has a steroid core structure, and the triterpenoid saponin differs from a saponin based on an alkaloid glycoside such as tomatidine in that such saponin comprising alkaloid glycoside has an alkaloid core structure. The term “conjugate” has its regular scientific meaning and here refers to at least a first molecule that is covalently bound through chemical bonds to at least a second molecule, therewith forming a covalently coupled assembly comprising or consisting of the first molecule and the second molecule. Typical conjugates are an ADC, an AOC, and SO1861-EMCH (EMCH linked to the aldehyde group of the aglycone core structure of the saponin). The term “tumor cell-specific surface molecule” and the term “tumor cell-specific receptor” have their regular scientific meaning and here refer to a molecule or a receptor that is expressed and exposed at the surface of a tumor cell and not at the surface of a healthy, non-cancerous cell, or is expressed at the surface of a healthy, non-cancerous cell to a lower extent than the level of expression (number of molecules/receptors) at the surface of the tumor cell. As used herein, the terms “nucleic acid”, “oligonucleotide” and “polynucleotide” are synonymous to one another and are to be construed as encompassing any polymeric molecule made of units, wherein a unit comprises a nucleobase (or simply “base” e.g., being a canonical nucleobase like adenine (A), cytosine (C), guanine (G), thymine (T), or uracil (U), or any known non-canonical, modified, or synthetic nucleobase like 5-methylcytosine, 5-hydroxymethylcytosine, xanthine, hypoxanthine, 7-methylguanine; 5,6-dihydrouracil etc.) or a functional equivalent thereof, which renders said polymeric molecule capable of engaging in hydrogen bond-based nucleobase pairing (such as Watson–Crick base pairing) under appropriate hybridisation conditions with naturally-occurring nucleic acids such as deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), which naturally-occurring nucleic acids are to be understood being polymeric molecules made of units being nucleotides. Hence, from a chemistry perspective, the term nucleic acid under the present definition can be construed as encompassing polymeric molecules that chemically are DNA or RNA, as well as polymeric molecules that are nucleic acid analogues, also known as xeno nucleic acids (XNA) or artificial nucleic acids, which are polymeric molecules wherein one or more (or all) of the units are modified nucleotides or are functional equivalents of nucleotides. Nucleic acid analogues are well known in the art and due to various properties, such as improved specificity and/or affinity, higher binding strength to their target and/or increased stability in vivo, they are extensively used in research and medicine. Typical examples of nucleic acid analogues include but are not limited to locked nucleic acid (LNA) (that is also known as bridged nucleic acid (BNA)), phosphorodiamidate morpholino oligomer (PMO also known as Morpholino), peptide nucleic acid (PNA), glycol nucleic acid (GNA), threose nucleic acid (TNA), hexitol nucleic acid (HNA), 2’-deoxy-2’-fluoroarabinonucleic acid (FANA or FNA), 2’-deoxy-2’-fluororibonucleic acid (2’-F RNA or FRNA); altritol nucleic acids (ANA), cyclohexene nucleic acids (CeNA) etc. In accordance with the canon, length of a nucleic acid is expressed herein the number of units from which a single strand of a nucleic acid is build. Because each unit corresponds to exactly one nucleobase capable of engaging in one base pairing event, the length is frequently expressed in so called "base pairs" or "bp" regardless whether the nucleic acid in question is a single stranded (ss) or double stranded (ds) nucleic acid. In naturally-occurring nucleic acids 1 bp corresponds to 1 nucleotide, abbreviated to 1 nt. For example, a single stranded nucleic acid made of 1000 nucleotides (or a double stranded nucleic acid made of two complementary strands each of which is made of 1000 nucleotides) is described as having a length of 1000 base pairs or 1000 bp, which length can also be expressed as 1000 nt or as 1 kilobase that is abbreviated to 1 kb.2 kilobases or 2 kb are equal to the length of 2000 base pair which equates 2000 nucleotides of a single stranded RNA or DNA. To avoid confusion however, in view of the fact the nucleic acids as defined herein may comprise or consist of units not only chemically being nucleotides but also being functional equivalents thereof, the length of nucleic acids will preferentially be expressed herein in "bp" or "kb" rather than in the equally common in the art denotation "nt". In advantageous embodiments, the nucleic acid as disclosed herein is no longer than 1 kb, preferably no longer than 500 bp, most preferably no longer than 250 bp. In particularly advantageous embodiments, the nucleic acid is an oligonucleotide (or simply an oligo) defined as nucleic acid no longer than 100 bp, i.e. in accordance with the above provided definition, being any polymeric molecule made of no more than 100 units, wherein each unit comprises a nucleobase or a functional equivalent thereof, which renders said oligonucleotide capable of engaging in hydrogen bond-based nucleobase pairing under appropriate hybridisation conditions with DNA or RNA. Within the ambit of said definition, it will immediately be appreciated that the disclosed herein oligonucleotides can comprise or consist of units not only being nucleotides but also being synthetic equivalents thereof. In other words, from a chemistry perspective, as used herein the term oligonucleotide will be construed as possibly comprising or consisting of RNA, DNA, or a nucleic acid analogue such as but not limited to LNA (BNA), PMO (Morpholino), PNA, GNA, TNA, HNA, FANA, FRNA, ANA, CeNA and/or the like. The term “RNAi-mediated gene-targeting” has its regular scientific meaning and here refers to the in vivo, ex vivo or in vitro approach of influencing functioning of the gene in a cell by transferring into said cell an oligonucleotide, such as a small double-stranded RNA molecule, that targets mRNA involved in transcription of the gene: for example, small double-stranded RNA molecules are capable of efficiently triggering RNAi silencing of specific genes. The term “bridged nucleic acid”, or “BNA” in short, or “locked nucleic acid” or “LNA” in short or 2'-O,4'-C-aminoethylene or 2'-O,4'-C-aminomethylene bridged nucleic acid (BNANC), has its regular scientific meaning and here refers to a modified RNA nucleotide. A BNA is also referred to as ‘constrained RNA molecule’ or ‘inaccessible RNA molecule’. A BNA monomer can contain a five- membered, six-membered or even a seven-membered bridged structure with a “fixed” C3’-endo sugar puckering. The bridge is synthetically incorporated at the 2’, 4’-position of the ribose to afford a 2’, 4’-BNA monomer. A BNA monomer can be incorporated into an oligonucleotide polymeric structure using standard phosphoramidite chemistry known in the art. A BNA is a structurally rigid oligonucleotide with increased binding affinity and stability. The term “BNA” also refers to BNANC or 2',4'-BNANC (2'-O,4'-aminoethylene bridged nucleic acid) and here refers to an oligonucleotide that contains one or more nucleotide building blocks with a six-member bridged structure with an N-O linkage, and with an (N-H) or (N-Me) residue. The term “payload” has its regular scientific meaning and here refers to a biologically active molecule, such as for example a cytotoxic (anti-cancer) drug molecule. The term “proteinaceous” has its regular scientific meaning and here refers to a molecule comprising at least two amino acid residues linked via a peptide bond with each other so that the molecule relates to, resembles, or is a polypeptide or a protein, meaning that the molecule possesses, to some degree, the physicochemical properties characteristic of a protein, is of protein, relating to protein, containing protein, pertaining to protein, consisting of protein, resembling protein, or being a protein. The term “proteinaceous” as used in for example ‘proteinaceous molecule’ refers to the presence of at least two amino acid residues linked via a peptide bond with each other so that at least a part of the molecule that resembles or is a protein, wherein ‘protein’ is to be understood to include a chain of amino-acid residues at least two residues long, thus including a peptide, a polypeptide and a protein and an assembly of proteins or protein domains. In the proteinaceous molecule, the at least two amino-acid residues are for example linked via (an) amide bond(s), such as (a) peptide bond(s). In the proteinaceous molecule, the amino-acid residues are natural amino-acid residues and/or artificial amino-acid residues such as modified natural amino- acid residues. It is preferred that a proteinaceous molecule is a molecule comprising at least two amino-acid residues, preferably between 2 and about 2.000 amino-acid residues. Also preferred is a proteinaceous molecule that is a molecule comprising from 2 to 20 (typical for a peptide) amino acids. Also preferred is a proteinaceous molecule that is a molecule comprising from 21 to 1.000 amino acid residues (typical for a polypeptide, a protein, a protein domain, such as an antibody, a Fab, an scFv, a ligand for a receptor such as EGF). Preferably, the amino-acid residues are (typically) linked via (a) peptide bond(s). According to the invention, said amino-acid residues are or comprise (modified) (non-)natural amino acid residues. The term “binding molecule” has its regular scientific meaning and here refers to a molecule capable of specifically binding to another molecule such as a cell-surface molecule, e.g. a cell- surface receptor. Typical binding molecules are peptides, proteins, non-protein molecules, cell- surface receptor ligands, protein ligands, that can bind to e.g. a protein, a lipid, a (poly)saccharide, such as a cell-surface receptor or a cell-surface molecule. “Specifically binding” here refers to specific and selective binding with higher affinity than non-specific background binding. The term “moiety” has its regular scientific meaning and here refers to a molecule that is bound, linked, conjugated to a further molecule, linker, assembly of molecules, etc., and therewith forming part of a larger molecule, conjugate, assembly of molecules. Typically, a moiety is an molecule that is covalently bound to another molecules, involving one or more chemical groups initially present on the effector molecule. For example, saporin is a typical effector molecule. As part of an antibody-drug conjugate, the saporin is a typical effector moiety in the ADC. As part of an antibody-oligonucleotide conjugate, an AON such as a BNA or an siRNA is a typical effector moiety in the AOC. The term “aglycone core structure” has its regular scientific meaning and here refers to the aglycone core of a saponin without the one or two carbohydrate antenna or saccharide chains (glycans) bound thereto. For example, quillaic acid is the aglycone core structure for SO1861, QS- 7 and QS-21. Typically, the glycans of a saponin are mono-saccharides or oligo-saccharides, such as linear or branched glycans. The term “QS-21” (also referred to as “QS21”), unless further specified, refers to any one of the isomers of QS-21. As will be understood by the skilled person, a typical natural extract comprising QS-21 will comprise a mixture of the different isomers of QS-21. However, through purification or (semi-)synthetic routes, a single isomer can be isolated. The term “Saponinum album” has its normal meaning and here refers to a mixture of saponins produced by Merck KGaA (Darmstadt, Germany) containing saponins from Gypsophila paniculata and Gypsophila arostii, containing SA1657 and mainly SA1641. The term “Quillaja saponin” has its normal meaning and here refers to the saponin fraction of Quillaja saponaria and thus the source for all other QS saponins, mainly containing QS-18 and QS-21. “QS-21” or “QS21” has its regular scientific meaning and here refers to a mixture of QS-21 A-apio (~63%), QS-21 A-xylo (~32%), QS-21 B-apio (~3.3%), and QS-21 B-xylo (~1.7%). Similarly, “QS-21A” has its regular scientific meaning and here refers to a mixture of QS-21 A-apio (~65%) and QS-21 A-xylo (~35%). Similarly, “QS-21B” has its regular scientific meaning and here refers to a mixture of QS-21 B-apio (~65%) and QS-21 B-xylo (~35%). The term “Quil-A” refers to a commercially available semi-purified extract from Quillaja saponaria and contains variable quantities of more than 50 distinct saponins, many of which incorporate the triterpene-trisaccharide substructure Gal-(1→2)-[Xyl-(1→3)]-GlcA- at the C-3beta- OH group found in QS-7, QS-17, QS18, and QS-21. The saponins found in Quil-A are listed in van Setten (1995), Table 2 [Dirk C. van Setten, Gerrit van de Werken, Gijsbert Zomer and Gideon F. A. Kersten, Glycosyl Compositions and Structural Characteristics of the Potential Immuno-adjuvant Active Saponins in the Quillaja saponaria Molina Extract Quil A, RAPID COMMUNICATIONS IN MASS SPECTROMETRY, VOL. 9,660-666 (1995)]. Quil-A and Quillaja saponin are fractions of saponins from Quillaja saponaria and both contain a large variety of different saponins with largely overlapping content. The two fractions differ in their specific composition as the two fractions are gained by different purification procedures. The term “QS1861” and the term “QS1862” refer to QS-7 and QS-7 api. QS1861 has a molecular mass of 1861 Dalton, QS1862 has a molecular mass of 1862 Dalton. QS1862 is described in Fleck et al. (2019) in Table 1, row no.28 [Juliane Deise Fleck, Andresa Heemann Betti, Francini Pereira da Silva, Eduardo Artur Troian, Cristina Olivaro, Fernando Ferreira and Simone Gasparin Verza, Saponins from Quillaja saponaria and Quillaja brasiliensis: Particular Chemical Characteristics and Biological Activities, Molecules 2019, 24, 171; doi:10.3390/molecules24010171]. The described structure is the api-variant QS1862 of QS-7. The molecular mass is 1862 Dalton as this mass is the formal mass including a proton at the glucuronic acid. At neutral pH, the molecule is deprotonated. When measuring in mass spectrometry in negative ion mode, the measured mass is 1861 Dalton. The term “saccharide chain” has its regular scientific meaning and here refers to any of a glycan, a carbohydrate antenna, a single saccharide moiety (monosaccharide) or a chain comprising multiple saccharide moieties (oligosaccharide, polysaccharide). The saccharide chain can consist of only saccharide moieties or may also comprise further moieties such as any one of 4E-Methoxycinnamic acid, 4Z-Methoxycinnamic acid, and 5-O-[5-O-Ara/Api-3,5-dihydroxy-6- methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), such as for example present in QS-21. The terms “SO1861” and “SO1862” refer to the same saponin of Saponaria officinalis, though in deprotonated form or api form, respectively. The molecular mass is 1862 Dalton as this mass is the formal mass including a proton at the glucuronic acid. At neutral pH, the molecule is deprotonated. When measuring the mass using mass spectrometry in negative ion mode, the measured mass is 1861 Dalton. Similarly, the terms “SO1831” and “SO1832” refer to the same saponin of Saponaria officinalis, though in deprotonated form or api form, respectively. The molecular mass is 1832 Dalton as this mass is the formal mass including a proton at the glucuronic acid. At neutral pH, the molecule is deprotonated. When measuring the mass using mass spectrometry in negative ion mode, the measured mass is 1831 Dalton. The term “Api/Xyl-“ or “Api- or Xyl-“ in the context of the name of a saccharide chain has its regular scientific meaning and here refers to the saccharide chain either comprising an apiose (Api) moiety, or comprising a xylose (Xyl) moiety. The term “transformation” has its regular scientific meaning and here refers to the chemical transformation or modification of a first functional group or first chemical group or first chemical moiety such that a second functional group or second chemical group or second chemical moiety is provided. An example is the transformation of an aldehyde group carbonyl group into a semicarbazone functional group through reaction with a semicarbazide. The term "antibody" as used herein is used in the broadest sense, which may refer to an immunoglobulin (Ig) defined as a protein belonging to the class IgG, IgM, IgE, IgA, or IgD (or any subclass thereof), or a functional binding fragment or binding domain of an immunoglobulin. In the context of the present invention, a "binding fragment" or a “binding domain” of an immunoglobulin or of an antibody is defined as antigen-binding fragment or -domain or other derivative of a parental immunoglobulin that essentially maintains the antigen binding activity of such parental immunoglobulin. Functional fragments and functional domains are antibodies in the sense of the present invention even if their affinity to the antigen is lower than that of the parental immunoglobulin. "Functional fragments and -domains" in accordance with the invention include, but are not limited to, F(ab')2 fragments, Fab' fragments, Fab fragments, scFv, dsFv, single-domain antibody (sdAb), monovalent IgG, scFv-Fc, reduced IgG (rIgG), minibody, diabodies, triabodies, tetrabodies, Fc fusion proteins, nanobodies, variable V domains such as VHH, Vh, and other types of antigen recognizing immunoglobulin fragments and domains. The fragments and domains may be engineered to minimize or completely remove the intermolecular disulphide interactions that occur between the CH1 and CL domains. Functional fragment and –domains offer the advantage of greater tumor penetration because of their smaller size. In addition, the functional fragment or – domain can be more evenly distributed throughout the tumor mass as compared to whole immunoglobulin. The term “antibody-drug conjugate” or “ADC” has its regular scientific meaning and here refers to any conjugate of an antibody such as an IgG, an immunoglobulin, an immunoglobulin binding fragment, a binding derivative or binding fragment or binding domain of an antibody such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single- domain antibody (sdAb), preferably a VHH, a ligand for a cell-surface molecule such as a receptor such as EGF and a cytokine, multiple VH domains, single-domain antibodies, VHH, or camelid VH, etc., and any molecule that can exert a therapeutic effect when contacted with cells of a subject such as a human patient, such as an active pharmaceutical ingredient, a toxin, an oligonucleotide, an enzyme, a small molecule drug compound, etc. The term “antibody-oligonucleotide conjugate” or “AOC” has its regular scientific meaning and here refers to any conjugate of an antibody such as an IgG, an immunoglobulin, an immunoglobulin binding fragment, a binding derivative or binding fragment or binding domain of an antibody such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, a ligand for a cell-surface molecule such as a receptor such as EGF and a cytokine, multiple VH domains, single-domain antibodies, VHH, or camelid VH, etc., and any oligonucleotide molecule that can exert a therapeutic effect when contacted with cells of a subject such as a human patient, such as an oligonucleotide selected from a natural or synthetic string of nucleic acids encompassing DNA, modified DNA, RNA, mRNA, modified RNA, synthetic nucleic acids, presented as a single-stranded molecule or a double- stranded molecule, such as a BNA, an antisense oligonucleotide (ASO), a short or small interfering RNA (siRNA; silencing RNA), an anti-sense DNA, anti-sense RNA, etc. The term “linker” has its regular scientific meaning, and linkers are commonly known in the art of bioconjugation. Common linkers are for example described in G.T. Hermanson (Bioconjugation Techniques, Third edition, Elsevier, 2013, ISBN: 978-0-12-382239-0). Here, the term linker refers to a chemical moiety or a linear stretch of amino-acid residues complexed through peptide bonds, which is suitable for covalently attaching (binding) a first molecule, such as a saponin, to another molecule, e.g. to a (proteinaceous) ligand or to an effector molecule or to a scaffold, for example composed of or comprising amino-acid residues, nucleic acids, etc. Typically, the linker comprises a chain of atoms linked by chemical bonds. Any linker molecule or linker technology known in the art can be used in the present disclosure. Where indicated, the linker is a linker for covalently binding of molecules through a chemical group on such a molecule suitable for forming a covalent linkage or bond with the linker. The linker may be a non-cleavable linker, e.g., the linker is stable in physiological conditions. The linker may be a cleavable linker, e.g. a linker that is cleavable, in the presence of an enzyme or at a particular pH range or value, or under physiological conditions such as intracellular conditions in the endosomes such as the late endosomes and the lysosomes of mammalian cells such as human cells. Exemplary linkers that can be used in the context of the present disclosure include, but is not limited to, N-ε- maleimidocaproic acid hydrazide (EMCH), succinimidyl 3-(2-pyridyldithio)propionate or 3-(2- Pyridyldithio)propionic acid N-hydroxysuccinimide ester (SPDP), a linker represented by a maleimide moiety according to formula (II)a or formula (II)b,
Figure imgf000056_0001
or an azide moiety according to formula (II)c
Figure imgf000056_0003
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6, and W is a thiol functional group according to formula (III), wherein
Figure imgf000056_0002
p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2, and 1- [Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxid hexafluorophosphate (HATU). The term “effector molecule”, or “effector moiety” when referring to the effector molecule as part of e.g. a covalent conjugate, has its regular scientific meaning and here refers to a molecule or moiety that has an effect on any one or more of a target molecule and/or proximally to any one or more of a target molecule and/or that can selectively bind to any one or more of a target molecule, wherein the target molecules are for example: a protein, a peptide, a carbohydrate, a saccharide such as a glycan, a (phospho)lipid, a nucleic acid such as DNA, RNA, an enzyme, and regulates the biological activity of such one or more target molecule(s). The effector molecule is for example a molecule selected from any one or more of a small molecule such as a drug molecule, a toxin such as a protein toxin, an oligonucleotide such as an AON such as a BNA, a xeno nucleic acid or an siRNA, an enzyme, a peptide, a protein, or any combination thereof. Thus, for example, an effector molecule or an effector moiety is a molecule or moiety selected from any one or more of a small molecule such as a drug molecule, a toxin such as a protein toxin, an oligonucleotide such as an AON such as a BNA, a xeno nucleic acid or an siRNA, an enzyme, a peptide, a protein, or any combination thereof, that can selectively bind to any one or more of the target molecules: a protein, a peptide, a carbohydrate, a saccharide such as a glycan, a (phospho)lipid, a nucleic acid such as DNA, RNA, an enzyme, and that upon binding to the target molecule regulates the biological activity of such one or more target molecule(s). An effect can include, but is not limited to, biological effect, a therapeutic effect, an imaging effect, and/or a cytotoxic effect. Typically, an effector molecule or moiety can exert a biological effect inside a cell such as a mammalian cell such as a human cell, such as in the cytosol of said cell. At a molecular or cellular level, an effect can include, but is not limited to, promotion or inhibition of the target's activity, labelling of the target, and/or cell death. Typical effector molecules and effector moieties are thus protein toxins, drug molecules, plasmid DNA, toxins such as toxins comprised by antibody-drug conjugates (ADCs), oligonucleotides such as an AON such as an siRNA, BNA, nucleic acids comprised by an antibody- oligonucleotide conjugate (AOC), enzymes. For example, an effector molecule or moiety is a molecule which can act as a ligand that can increase or decrease (intracellular) enzyme activity, gene expression, or cell signalling. The effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based. The effector moiety is not the saponin derivative or the saponin conjugate of the invention. The term “HSP27” relates to a BNA oligonucleotide molecule which silences the expression of HSP27 in the cells. The term “ApoB”, or “ApoBBNA”, or “ApoB#02” relates to a BNA oligonucleotide molecule which silences the expression of apoB in the cells. The terms first, second, third and the like in the description and in the claims, are used for distinguishing between for example similar elements, compositions, constituents in a composition, or separate method steps, and not necessarily for describing a sequential or chronological order. The terms are interchangeable under appropriate circumstances and the embodiments of the invention can operate in other sequences than described or illustrated herein, unless specified otherwise. The term ‘L’ as used such as in a saponin derivative or an antibody-saponin conjugate or construct comprising a linker, represents ‘labile linker’ which is cleaved under slightly acid conditions (pH < 6.6, such as pH 4.0 – 5.5) in the endosome, endolysosome and in the lysosome of mammalian cells, such as human cells, such as a human tumor cell. The term “GalNAc” has its regular scientific meaning and here refers to N- acetylgalactosamine and to the IUPAC name thereof: 2-(acetylamino)-2-deoxy-D-galactose. The term “(GalNAc)3Tris” has its regular scientific meaning in for example the field of siRNA- based therapy, and here refers to a moiety comprising three GalNAc units each separately covalently bound to the hydroxyl groups of tris(hydroxymethyl)aminomethane (Tris) (IUPAC name: 2-amino-2-(hydroxymethyl) propane-1,3-diol), preferably via at least one linker. (GalNAc)3Tris can exist as a free amine comprising molecule or may be further functionalized via the remaining amine binding site, for example to form the (GalNAc)3Tris-moiety comprising conjugates described herein. The embodiments of the invention described herein can operate in combination and cooperation, unless specified otherwise. Furthermore, the various embodiments, although referred to as “preferred” or “e.g.” or “for example” or “in particular” and the like are to be construed as exemplary manners in which the invention may be implemented rather than as limiting the scope of the invention. The term “comprising”, used in the claims, should not be interpreted as being restricted to for example the elements or the method steps or the constituents of a compositions listed thereafter; it does not exclude other elements or method steps or constituents in a certain composition. It needs to be interpreted as specifying the presence of the stated features, integers, (method) steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a method comprising steps A and B” should not be limited to a method consisting only of steps A and B, rather with respect to the present invention, the only enumerated steps of the method are A and B, and further the claim should be interpreted as including equivalents of those method steps. Thus, the scope of the expression “a composition comprising components A and B” should not be limited to a composition consisting only of components A and B, rather with respect to the present invention, the only enumerated components of the composition are A and B, and further the claim should be interpreted as including equivalents of those components. The term “DAR” has its regular scientific meaning of Drug/Antibody Ratio and refers to the average drug to antibody ratio for a given preparation of antibody drug conjugate (ADC) and here refers to a ratio of the amount of bound SO1861 moieties, or SPT001, or bound payload, e.g. an AON such as ApoB BNA with respect to the conjugate molecule. In addition, reference to an element or a component by the indefinite article "a" or "an" does not exclude the possibility that more than one of the element or component are present, unless the context clearly requires that there is one and only one of the elements or components. The indefinite article "a" or "an" thus usually means "at least one". BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be discussed in more detail below, with reference to the attached drawings, in which Figure 1: SO1861-SC-Mal synthesis Figure 2A-B: SO1861-semicarbazone (‘SO1861-SC’) synthesis (Figure 2A); SO1861-SC-Mal (blocked) synthesis (Figure 2B) Figure 3: SO1861-EMCH synthesis Figure 4A-C: Dendron4-amine synthesis. Synthesis of intermediate 5 and intermediate 6 (Figure 4A); Synthesis of intermediate 7 and intermediate 9 (Figure 4B); Synthesis of intermediate 10 (Figure 4C) Figure 4 D: SO1861-EMCH and SO1861-SC-Mal structure Figure 4 E: Dendron-(EMCH-SO1861)4-amine and Dendron-(SC-SO1861)4-amine synthesis Figure 4 F: Dendron-(EMCH-SO1861)4-azide and Dendron-(SC-SO1861)4-azide synthesis Figure 4 G: Dendron-(EMCH-SO1861)4-maleimide1 and Dendron-(SC-SO1861)4-maleimide1 synthesis Figure 4 H: Dendron-(EMCH-SO1861)4-maleimide2 and Dendron-(SC-SO1861)4-maleimide2 synthesis Figure 5 A-D: Dendron8-amine synthesis. Synthesis of intermediate 13 (Figure 5A); Synthesis of intermediate 14 (Figure 5B); Synthesis of intermediate 15 (Figure 5C); Synthesis of intermediate 16 (Figure 5D) Figure 5 E: Dendron-(EMCH-SO1861)8-amine and Dendron-(SC-SO1861)8-amine synthesis Figure 5 F: Dendron-(EMCH-SO1861)8-azide and Dendron-(SC-SO1861)8-azide synthesis Figure 5 G: Dendron-(EMCH-SO1861)8-maleimide1 and Dendron-(SC-SO1861)8-maleimide1 synthesis Figure 5 H: Dendron-(EMCH-SO1861)8-maleimide2 and Dendron-(SC-SO1861)8-maleimide2 synthesis Figure 6: Structure of hCD71mab-SC-SO1861 conjugate. Graphical representation of mAb- semicarbazone-SO1861 (DAR4). The derivatised saponin SO1861-SC-Mal is covalently linked to the central monoclonal antibody (e.g., an IgG) via covalent bond formation between cysteine residues of the antibody and the maleimide group of the derivatised SO1861. Four SO1861 moieties are bound to the antibody. Figure 7A-B: Structure of hCD71mab-dendron(EMCH-SO1861)4 conjugate. SO1861-hydrazone moiety (Figure 7A); antibody-dendron(EMCH-SO1861)4 conjugate (Figure 7B) Figure 8A-B: Structure of hCD71mab-dendron(SC-SO1861)8 conjugate. SO1861-semicarbazone moiety and dendron(SC-SO1861)8-maleimide1 (Figure 8A); antibody-dendron(SC-SO1861)8 conjugate (Figure 8B). ‘SPT001’ is SO1861. Figure 9A-B: Release kinetic assay of SO1861-EMCH (formula (4)) (Figure 9 A) and SO1861-SC- Mal (blocked) (Molecule (VIII)) (Figure 9 B) at various pH. Figure 10A-B: Cell killing assay (MTS) of SO1861-SC-Mal + 5 pM EGF-dianthin on HeLa (Figure 10 A) and A431 (Figure 10 B) cell lines. Note: the legend to Figure 10A and Figure 10B is the same and is displayed next to the graphs in Figure 10A. Figure 11A-B: Cell killing assay (MTS) of SO1861-SC-Mal + 10 pM Cetuximab-saporin on HeLa (Figure 11 A) and A431 (Figure 11 B) cell lines. Note: the legend to Figure 11A and Figure 11B is the same and is displayed next to the graphs in Figure 11A. Figure 12A-B: Cell killing assay (MTS) of SO1861-SC-Mal + 50 pM Trastuzumab-saporin on HeLa (Figure 12 A) and A431 (Figure 12 B) cell lines. Note: the legend to Figure 12A and Figure 12B is the same and is displayed next to the graphs in Figure 12A. Figure 13A-B: HSP27 gene silencing of SO1861-SC-Mal + Tmab-HSP27BNA on A431 cell lines. (Figure 13 A) Relative HSP27 expression in the absence of saponin. (Figure 13 B) Relative HSP27 expression under influence of saponin analogues SO1861-EMCH and SO1861-SC-Mal and of wild type (non-modified, non-derivatised) saponin SO1861. Figure 14A-B: Cell killing assay (MTS) of SO1861-SC-Mal, SO1861-SC, SO1861-EMCH and non- derivatised SO1861 on HeLa (Figure 14 A) and A431 (Figure 14B) cell lines. Note: the legend to Figure 14A and Figure 14B is the same and is displayed next to the graphs in Figure 14A. ‘SC’ is ‘semicarbazone’. Figure 15: Hemolytic activity of modified SO1861 (SO1861 derivatives) and non-derivatised SO1861 on human red blood cells (RBC). Figure 16A-B: EGFR/CD71 targeted cell killing in A431 cells (Figure 16A) and CaSKi cells (Figure 16B). Cetuximab-(SC-SO1861)4, also called Cetuximab-SC-SO1861 (DAR 4) and Cetuximab- (EMCH-SO1861)4 titration + fixed concentration 10 pM CD71mab-saporin and controls on A431 cells (EGFR++/CD71+) and CaSKi cells (EGFR++/CD71+). Note: the legend to Figure 16A and Figure 16B is the same and is displayed next to the graphs in Figure 16B. Figure 17A-B: EGFR/CD71 targeted cell killing in HeLa cells (Figure 17A) and A2058 cells (Figure 17B). Cetuximab-(SC-SO1861)4 and Cetuximab-(EMCH-SO1861)4 titration + fixed concentration 10 pM CD71mab-saporin and controls on HeLa cells (EGFR+/-/CD71+) and A2058 cells (EGFR- /CD71+). Note: the legend to Figure 17A and Figure 17B is the same and is displayed next to the graphs in Figure 17B. Figure 18: HER2/CD71 targeted cell killing. Trastuzumab-(SC-SO1861)4 or Trastuzumab-(EMCH- SO1861)4 titration + fixed concentration 10 pM CD71mab-saporin and controls on SK-BR3 cells (HER2++/CD71+). Figure 19A-B: HER2/CD71 targeted cell killing. (Figure 19 A, Figure 19 B) Trastuzumab-(SC- SO1861)4 or Trastuzumab-(Cys-EMCH-SO1861)4 titration + fixed concentration 10 pM CD71mab- saporin and controls on JIMT-1 cells (HER2+/-/CD71+) (Figure 19 A), and MDA-MB-468 (HER2- /CD71+) (Figure 19 B). Note: the legend to Figure 19A and Figure 19B is the same and is displayed next to the graphs in Figure 19B. Figure 20: EGFR/HER2 targeted gene silencing in A431 cells. Cetuximab-(SC-SO1861)4 and Cetuximab-(EMCH-SO1861)4 titration + fixed concentration 50 pM Trastuzumab-S-HSP27BNA and controls on A431 cells (EGFR++/HER2+/-). The term ‘S’ as used such as in an antibody- oligonucleotide conjugate represents ‘stable linker’, which is a non-cleavable linker in the endosome, endolysosome and in the lysosome of mammalian cells, such as human cells, such as a human tumor cell, thus under slightly acidic conditions (pH < 6.6, such as pH 4.0 – 5.5). Figure 21: Cell killing assay (MTS) of various cell lines treated with 5 pM EGFdianthin (Dia-EGF), 10 pM Cetuximab-saporin (Cet-SPRN), 50 pM Trastuzumab-saporin (Tras-SPRN) or 10 pM CD71- saporin (CD71-SPRN). Figure 22: HSP27 mRNA expression levels in A431 cells. Displayed is the relative HSP27 expression in A431 cells contacted with Cetuximab-(SC-SO1861)-HSP27 (DAR4/DAR2) and Cetuximab-(EMCH-SO1861)-HSP27 (DAR4/DAR2). The conjugates comprise two BNA molecules (DAR 2) and four SO1861 moieties (DAR 4). Figure 23A-F: CD71/EGFR targeted cell killing in SK-BR3 (Figure 23A), JIMT-1 (Figure 23B), HeLa (Figure 23C), and MDA-MB-468 cells (Figure 23D) A431 (Figure 23E) and A2058 (Figure 23F). SO1861-SC-Mal, CD71mAb-(SC-SO1861)4, CD71mAb-(EMCH-SO1861)4, CD71mAb- dendron(SC-SO1861)81.5 (average of ~12 SO1861 molecules) and CD71mAb-dendron(EMCH- SO1861)43.2 (on average of ~12 SO1861 molecules) titration + fixed concentration 5 pM EGFdianthin (fusion protein toxin). Figure 24: Relative apoB (ApoB100) expression analysis on primary human hepatocytes (A), HepG2 cell line (B), and Huh7 cell line (C) for different ApoB#02 conjugates. Figure 25: Relative apoB expression analysis in liver tissue of C57BL/6J mice. Figure 26: Serum apoB protein analysis C57BL/6J mice. NB, levels for 0.1 mg/kg ApoB#02 (196 hrs), 0.01 mg/kg (GalNAc)3-ApoB + 5 mg/kg (GalNAc)3-SO1861 (196 hrs and 336 hrs) and 0.1 mg/kg (GalNAc)3-ApoB + 5 mg/kg (GalNAc)3-SO1861 (196 hrs) are not reported. Figure 27: Serum LDL-cholesterol (LDL-C) analysis in C57BL/6J mice. Figure 28: Serum ALT analysis in C57BL/6J mice. Figure 29: ApoB expression analysis and cell viability assay on primary human hepatocytes for ApoB#02 conjugates. Figure 30: Relative apoB expression analysis in liver tissue of C57BL/6J mice. Figure 31: Serum apoB protein analysis in C57BL/6J mice. Figure 32: Serum LDL-cholesterol (LDL-C) analysis in C57BL/6J mice. Figure 33: Serum ALT analysis in C57BL/6J mice. Figure 34A-C: synthesis of trivalent GalNAc. Figure 35A-D: synthesis of trivalent GalNAc. Figure 36A-D: Trifunctional linker-(L-hydrazone-SO1861)-(L-BNA oligo)-(Trivalent-GalNAc) synthesis. Figure 37A-E: Trifunctional linker-(dendron(-L-hydrazone-SO1861)4)-(L-BNA oligo)-(Trivalent- GalNAc) synthesis. Note that the drawing of Figure 37 E encompasses two sheets, labelled Fig.37 E and Fig.37 E (continued), which two sheets together display the conjugation of molecule 21 with molecule 19, therewith forming conjugate molecule 22. Figure 38A-C: Trifunctional linker-(dendron(-L-hydrazone-SO1861)8)-(BNA oligo)-(Trivalent- GalNAc) synthesis. Note that the drawing of Figure 38 B encompasses two sheets, labelled Fig.38 B and Fig.38 B (continued), which two sheets together display the conjugation of molecule 24 with molecule 18, therewith forming conjugate molecule 25 (intermediate 12). Note that the drawing of Figure 38 C encompasses two sheets, labelled Fig. 38 C and Fig. 38 C (continued), which two sheets together display the conjugation of molecule 25 with molecule 21, therewith forming conjugate molecule 26. Figure 39A-C: Trifunctional linker-(L-semicarbazone-SO1861)- (BNA oligo) – (Trivalent-GalNAc) synthesis. Figure 40A-F: Trifunctional linker – (dendron(L-semicarbazone-SO1861)4) - (L-BNA oligo) - (Trivalent-GalNAc) synthesis. Note that the drawing of Figure 40 E encompasses two sheets, labelled Fig.40 E and Fig.40 E (continued), which two sheets together display the conjugation of molecule 40 with molecule 20, therewith forming conjugate intermediate 24. Figure 41A-D: Trifunctional linker – (dendron(L-semicarbazone-SO1861)8) - (L-BNA oligo) - (Trivalent-GalNAc) synthesis. Note that the drawing of Figure 41 A encompasses two sheets, labelled Fig.41 A and Fig.41 A (continued), which two sheets together display the conjugation of molecule 43 with molecule 37, therewith forming conjugate (molecule 44) intermediate 25. Note that the drawing of Figure 41 B encompasses two sheets, labelled Fig. 41 B and Fig. 41 B (continued), which two sheets together display the conjugation of molecule 44 with molecule 18, therewith forming conjugate molecule 45 (intermediate 26). Note that the drawing of Figure 41 C encompasses two sheets, labelled Fig.41 C and Fig.41 C (continued), which two sheets together display the conjugation of molecule 45 with molecule 20, therewith forming conjugate molecule 46 (intermediate 27). Figure 42: Trifunctional linker-(L-SPT001)-(blocked TCO)-(trivalent GalNAc synthesis Figure 43A-B: Trifunctional linker-(blocked DBCO)-(L-BNA oligo)-(trivalent GalNAc) synthesis Figure 44: Overview of conjugates obtainable by applying TFL methodology. Note that the drawing of Figure 44 encompasses two sheets, labelled Fig.44 and Fig.44 (continued), which two sheets together display the conjugation of Trifunctional linker labelled molecule 4 with Targeting ligand labelled molecule 41, Effector labelled molecule 12, and one of the Enhancers labelled molecule 3, 19, 25, 28, 40 and 45 or one of the Blocking agents for controls labelled molecule 5, 12a and 50, therewith forming a conjugate with the general conjugate structure as depicted in the box, comprising group R1 and group R2, wherein R1 is any one of the groups depicted next to the boxed conjugate and R2 is any one of the groups depicted next to the boxed conjugate. Figure 45: Graphic of antibody(-L-SC-SO1861)4 – (S-HSP27 BNA)2. The amino-acid residues labelled ‘Cys’ and ‘Lys’ are part of the amino-acid sequence of the antibody. DETAILED DESCRIPTION The present invention will be described with respect to particular embodiments, but the invention is not limited thereto but only by the claims. Surprisingly, the inventors have found that a saponin derivative based on a saponin comprising a triterpene aglycone core structure and at least one of a first saccharide chain ‘R1’ and a second saccharide chain ‘R2’ linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde group, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (I)
Figure imgf000062_0001
wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, X = O, P or S, and Y = NR3R4, wherein R3 and R4 independently represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, preferably one of R3 and R4 is H; or
Figure imgf000063_0001
, wherein n and m each are an integer independently selected from 1, 2, or 3, Z = CH2, O, S, P or NR5, and wherein R5 represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl, an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b,
Figure imgf000063_0002
(II)a (II)b or an azide moiety according to formula (II)c
Figure imgf000063_0003
(II)c wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6, and W is a thiol functional group according to formula (III),
Figure imgf000063_0004
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2, has a reduced toxicity when cell viability is considered of cells contacted with the saponin derivatives; has activity when potentiation of e.g. toxin cytotoxicity or AON-, such as BNA, mediated gene silencing is considered (without wishing to be bound by any theory: relating to similar or improved endosomal escape enhancing activity of the modified saponin), if the aldehyde functional group is transformed to a semicarbazone functional group according to formula (I); and/or has reduced hemolytic activity, when compared with the toxicity, activity and haemolytic activity of unmodified saponin. That is to say, the saponin derivative of the invention has at least one, preferably to, more preferably all three of: (i) a reduced toxicity when cell viability is considered of cells contacted with the saponin derivatives; (ii) enhanced activity when potentiation of e.g. toxin cytotoxicity or AON-mediated gene silencing such as BNA-mediated gene silencing is considered (without wishing to be bound by any theory: relating to similar or improved endosomal escape enhancing activity of the modified saponin), if the aldehyde functional group is transformed to a semicarbazone functional group according to formula (I); and/or (iii) reduced hemolytic activity, when compared with the toxicity, activity and haemolytic activity of unmodified saponin on which the saponin derivative is based. Therewith, the inventors provide saponin derivatives with an improved therapeutic window, since for the saponin derivatives the cytotoxicity is lower than cytotoxicity determined for their naturally occurring counterparts, the haemolytic activity is lower than haemolytic activity determined for the naturally occurring counterparts of the saponin derivatives, the ratio between IC50 values for cell toxicity and e.g. IC50 values for toxin potentiation or IC50 values for gene silencing is similar or increased, and/or since the ratio between IC50 values for saponin haemolytic activity and e.g. IC50 values for toxin potentiation or IC50 values for gene silencing is similar or increased. Reference is made to Table 3 and Table 4 of the examples for an overview of exemplified saponin derivatives for an overview of the cytotoxicity, haemolytic activity and endosomal escape enhancing activity (‘activity’), as well as an overview of the ratio between IC50 for cytotoxicity and IC50 for activity, and the ratio between IC50 for haemolytic activity and IC50 for activity. In addition, the inventors surprisingly established (tumor) cell killing by contacting such cells with a saponin conjugate of the current invention based on a saponin derivative of the current invention e.g. comprising a ligand such as an antibody or such as one or more GalNAc moieties such as three GalNAc moieties, for a cell-surface molecule such as a receptor such as CD71 (when the ligand is a CD71 binding antibody in the saponin conjugate) or such as ASGPR, preferably ASGPR1 (when the ligand is one or more GalNAc moieties, preferably three GalNAc moieties), together with an AOC such as an antibody – BNA conjugate, despite the medium to low expression of the cell-surface receptor targeted by the cell-surface molecule binding-molecule (e.g. antibody, such as anti-CD71 antibody) comprised by the saponin conjugate and/or despite the medium to low expression of the cell-surface receptor targeted by the AOC. The saponin derivative and, preferably, also the saponin conjugate of the invention comprise the semicarbazone functional group. For example, in a comparative example, such cell killing or gene silencing when cells are contacted with an ADC or AOC could not be established or only to a lower extent, when a saponin conjugate comprising the same cell-surface molecule binding-molecule (e.g., antibody) but comprising a hydrazone functional group (=N-N(H)-C(O)-) instead of the semicarbazone functional group, was contacted with the cells. Therewith, the inventors now provide for a more potent saponin derivative and a more potent saponin conjugate, when the activation or potentiating of an effector moiety such as an effector moiety comprised by an ADC or AOC, is considered, relating to the presence of the semicarbazone functional group with which the saponin is linked to the cell-surface molecule (such as a cell-surface receptor) binding molecule, for example an antibody or at least one sdAb capable of binding to said cell-surface molecule. Furthermore, the inventors have found that the saponin derivatives according to the invention comprising the semicarbazone functional group hydrolyses more rapidly and in a higher amount towards the corresponding native saponin comprising a “free” aldehyde functional group, as compared to saponin derivatives comprising a hydrazone functional group (=N-N(H)-C(O)-) known in the art, under acidic conditions which are the conditions present in endosomes and/or lysosomes of mammalian cells. This has the benefit that a lower amount of the saponin derivatives according to the invention should be administered to a patient in need of potentiation of e.g. an ADC or an AOC a gene-silencing oligonucleotide such as an AON such as a BNA, e.g. coupled to one or more GalNAc moieties, to obtain the same amount of native saponin comprising the “free” aldehyde to act as endosomal escape enhancers for targeted toxins or targeted oligonucleotides, compared to the required amount of saponin derivative comprising e.g. the hydrazone functional group (=N-N(H)-C(O)-). Without wishing to be bound by any theory, faster and more efficacious release of the saponin comprising the aldehyde functional group from the saponin derivative that comprises the semicarbazone functional group according to the invention, when compared to release of the saponin comprising the aldehyde functional group from the saponin derivative that comprises e.g. the hydrazone functional group, is at the basis for the improved activity of the saponin conjugate of the invention comprising a saponin derivative of the invention, such as a conjugate comprising the saponin, an oligonucleotide and a cell-surface receptor ligand such as one to three GalNAc moieties (for targeting (liver) cells expressing ASGPR), wherein the activity is the potentiation of the effector moiety activity such as a gene-silencing oligonucleotide, inside the cytosol or nucleus of the targeted cell by endosomal escape enhancement. Surprisingly, transformation (derivatisation) of the aldehyde group at C-23 of the aglycone of the saponin into a semicarbazone functional group according to formula (I), results in a decrease in cytotoxicity when such saponin derivatives are contacted with cells, i.e. various types of cells including but not limited to red blood cells. It is thus part of the invention that these series of saponin derivatives with decreased cytotoxicity are provided, wherein the decrease in cytotoxicity is relative to the cytotoxicity as determined for the unmodified naturally occurring saponin counterparts. The saponin derivatives can be formed from such naturally occurring saponins, such as SO1861, equally active SO1832 and QS-21 (isoforms), preferably from SO1861 or SO1832. When the decrease in cytotoxicity is considered, saponin derivatives according to the invention, are equally suitable, when saponins with decreased cytotoxicity are to be provided. The saponin SO1832 consists of the quillaic acid aglycone core with the carbohydrate substituent Gal-(1→2)-[Xyl-(1→3)]-GlcA- at the C-3beta-OH group and with the carbohydrate substituent Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc- at the C-28-OH group (See also Table A1). The chemical formula is C82H128O45 and the exact mass is 1832,77 Dalton. The saponin structure of SO1832 is according to molecule (SO1832):
Figure imgf000066_0001
(SO1832). The inventors have also found that the modifications (derivatisations) lead to an increased critical micelle concentration (CMC) when compared with the corresponding unmodified saponin. For example, the saponin derivative according to formula (VIII) (or Molecule (VIII)) has an increased CMC when compared to their corresponding underivatised saponin and are hence explicitly envisaged embodiments of the invention. Without wishing to be bound by any theory, it is believed that an increased CMC is advantageous for several reasons. For example, an increased CMC may facilitate the use of the modified saponins (saponin derivatives) in subsequent conjugation reactions since free molecules are generally more susceptible to conjugation reactions than molecules ordered in a micellar structure. Furthermore, in case the saponin derivatives need to exert a biological function (e.g. in an in vivo treatment or ex vivo method or in vitro method), for example in case the saponin derivatives are used as such or even in case they are released in situ after cleavage from a carrier or another entity, an increased CMC when compared to unmodified saponin is advantageous since the free saponin molecules will be more readily available to interact with their biological target than in case these saponin derivatives are ordered in a micellar structure. An increased CMC may also be useful to facilitate the large-scale production and concentration of the saponin derivatives since at concentrations beyond (above) the critical micellar concentration, saponins form micelles which hinder isolation (e.g. using preparative HPLC). Surprisingly, for the saponin derivatives according to the invention, the observed increased CMC was not associated with increased cytotoxicity or haemolytic activity. The relationship between CMC and cytotoxicity is not predictable and complex, as can for example be seen from the data in Table 2 of de Groot et al. (“Saponin interactions with model membrane systems–Langmuir monolayer studies, hemolysis and formation of ISCOMs”, Planta medica 82.18 (2016): 1496-1512.), which shows that, taking α- Hederin as the reference point, an increase in CMC may be associated with an increase in general cytotoxicity (as is the case for Digitonin) but may just as well be associated with a decrease in cytotoxicity (as is the case for Glycyrrhizin and Hederacoside C). Furthermore, for the saponin derivative according to formula (VIII) the increased CMC is also associated with an increased ratio: IC50 hemolysis / IC50 activity, compared to the corresponding free saponin, such that this saponin derivative is a particularly preferred embodiment of the invention. The inventors thus provide saponin derivatives with an improved therapeutic window when cytotoxicity is considered and/or when haemolytic activity is considered, and when the potentiation of e.g. toxins is considered and/or when an increased CMC compared to the corresponding underivatised saponin is considered. Such saponin derivatives of the invention are in particular suitable for application in a therapeutic regimen involving e.g. an ADC or an AOC for the prophylaxis or treatment of e.g. a cancer, or a GalNAc-oligonucleotide conjugate for the prophylaxis or treatment of e.g. a cancer, hypercholesterolemia, cardiovascular disease or enhanced level of LDL- cholesterol above normal levels for healthy subjects in a (human) subject in need thereof. The safety of such saponin derivatives is improved when cytotoxicity and/or haemolytic activity is considered, especially when such saponin derivatives are administered to a patient in need of e.g. treatment with an ADC or with and AOC or with a conjugate comprising at least one GalNAc moiety and comprising an oligonucleotide, e.g. an AON such as a BNA for silencing a gene such as HSP27 and apoB. An aspect of the invention relates to a saponin derivative based on a saponin comprising a triterpene aglycone core structure and at least one of a first saccharide chain ‘R1’ and a second saccharide chain ‘R2’ linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde group, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (I)
Figure imgf000067_0002
wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, X = O, P or S, and Y = NR3R4, wherein R3 and R4 independently represent H or a covalently bound linker, preferably one of R3 and R4 is H; or
Figure imgf000067_0001
, wherein n and m each are an integer independently selected from 1, 2, or 3, Z = CH2, O, S, P or NR5, and wherein R5 represents H or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000068_0004
or an azide moiety according to formula (II)c
Figure imgf000068_0001
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6, and W is a thiol functional group according to formula (III)
Figure imgf000068_0002
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. An aspect of the invention relates to a saponin derivative based on a saponin comprising a triterpene aglycone core structure and at least one of a first saccharide chain ‘R1’ and a second saccharide chain ‘R2’ linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde group, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (I)
Figure imgf000068_0003
wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, X = O, P or S, and Y = NR3R4, wherein R3 and R4 independently represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, preferably one of R3 and R4 is H; or
Figure imgf000069_0001
, wherein n and m each are an integer independently selected from 1, 2, or 3, Z = CH2, O, S, P or NR5, and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl, an unsubstituted C2 – C10 straight chain or branched alkynyl, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000069_0002
or an azide moiety according to formula (II)c
Figure imgf000069_0005
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6, and W is a thiol functional group according to formula (III)
Figure imgf000069_0003
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. An aspect of the invention relates to a saponin derivative based on a saponin comprising a triterpene aglycone core structure and at least one of a first saccharide chain ‘R1’ and a second saccharide chain ‘R2’ linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde group, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (I)
Figure imgf000069_0004
wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, X = O, P or S, and Y = NR3R4, wherein R3 and R4 independently represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, preferably one of R3 and R4 is H; or
Figure imgf000070_0003
, wherein n and m each are an integer independently selected from 1, 2, or 3, Z = CH2, O, S, P or NR5, and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl, an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000070_0004
( ) ( ) or an azide moiety according to formula (II)c
Figure imgf000070_0001
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6, and W is a thiol functional group according to formula (III)
Figure imgf000070_0002
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. Worded differently, the saponin derivative according to the invention is a saponin comprising a triterpene aglycone core structure and at least one of a first saccharide chain ‘R1’ and a second saccharide chain ‘R2’ linked to the aglycone core structure, wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide and the aglycone core structure comprises an aldehyde group which has been derivatised by reacting with a semicarbazide according to formula (3)
Figure imgf000071_0004
wherein X = O, P or S, Y = NR3R4, wherein R3 and R4 independently represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, preferably one of R3 and R4 is H, or
Figure imgf000071_0005
wherein n and m each are an integer independently selected from 1, 2, or 3, Z = CH2, O, S, P or NR5, and wherein R5 represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl, an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b,
Figure imgf000071_0001
(II)a (II)b or an azide moiety according to formula (II)c
Figure imgf000071_0002
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6, and W is a thiol functional group according to formula (III),
Figure imgf000071_0003
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is a monodesmosidic triterpene glycoside or a bidesmosidic triterpene glycoside, more preferably a bidesmosidic triterpene glycoside. A series of saponins known in the art have shown to enhance endosomal escape of molecules, which are most often bidesmosidic triterpene glycosides, although also a series of monodesmosidic triterpene glycosides have shown such enhancing activity. Table A1 summarizes the series of saponins for which endosomal escape enhancing activity has been established. Such saponins are good starting points for synthesising the saponin derivatives of the invention. In particular, SO1861 has proven to be a suitable natural saponin for derivatisation according to the invention. Since SO1832 has similar activity when compared to SO1861, as has been established by the inventors, also SO1832 is a suitable natural saponin for derivatisation according to the invention. Similarly, QS-21 can be a suitable natural saponin for derivatisation according to the invention, although the inventors established that the cytotoxicity and haemolytic activity of QS-21 is relatively higher than cytotoxicity and haemolytic activity of e.g., SO1861. An embodiment is the saponin derivative according to the invention, wherein the saponin derivative comprises an aglycone core structure selected from the group consisting of: 2alpha-hydroxy oleanolic acid; 16alpha-hydroxy oleanolic acid; hederagenin (23-hydroxy oleanolic acid); 16alpha,23-dihydroxy oleanolic acid; gypsogenin; quillaic acid; protoaescigenin-21(2-methylbut-2-enoate)-22-acetate; 23-oxo-barringtogenol C-21,22-bis(2-methylbut-2-enoate); 23-oxo-barringtogenol C-21(2-methylbut-2-enoate)-16,22-diacetate; digitogenin; 3,16,28-trihydroxy oleanan-12-en; gypsogenic acid, and derivatives thereof, preferably the saponin derivative comprises an aglycone core structure selected from quillaic acid and gypsogenin or derivatives thereof, more preferably the saponin derivative aglycone core structure is quillaic acid or a derivative thereof. Since the inventors now found that improved saponin derivatives can be provided with regard to decreased cytotoxicity and lower haemolysis of cells contacted with such derivatives, based on saponins of the triterpene glycoside type, basically any saponin with such endosomal escape enhancing activity as tested by the inventors, such as saponins having the aglycone of the afore embodiment and listed in Table A1, can be improved accordingly. Lowering toxicity and lowering haemolytic activity while preserving activity to a sufficiently high extent when potentiation of toxins and for example an AON such as BNAs is considered, is an important achievement by the inventors, when the widening of the therapeutic window of the saponin derivatives alone or in combination with e.g. an ADC or an AOC is considered. A sufficiently high dose of derivatised saponin can be applied in e.g. tumor therapy for a cancer patient in need thereof, while the (risk for) cytotoxic side-effects and the (risk for) undesired haemolytic activity exerted or induced by the saponin derivative is decreased when compared with the application of the natural saponin counterpart (i.e. the non-derivatised saponin). Improvements of the therapeutic window of the saponin derivatives of the invention are for example apparent for the exemplified saponin derivatives in Table 3 and Table 4: the ratio between the IC50 for either cytotoxicity, or haemolytic activity and the IC50 for endosomal escape enhancing activity are listed, as well as the haemolytic activity, cytotoxicity and the activity, and the CMC. An embodiment is the saponin derivative according to the invention, wherein the saponin derivative comprises an aglycone core structure selected from the group consisting of quillaic acid, gypsogenin, and derivatives thereof, preferably the saponin derivative comprises an aglycone core structure selected from the group consisting of quillaic acid and derivatives thereof, wherein the first saccharide chain R1, when present, is linked to the C3 atom (also denoted as ‘C-3’ atom) or the C28 atom (also denoted as ‘C-28’ atom) of the aglycone core structure, preferably to the C3 atom, and/or wherein the second saccharide chain R2, when present, is linked to the C28 atom of the aglycone core structure. Preferred are those saponin derivatives which are based on a saponin having both saccharide chains bound to the aglycone, but in general any saponin that displays endosomal escape enhancing activity is suitable for derivatisation according to the invention, for the purpose to provide single, double, or triple, preferably single or double derivatised saponins with lower cytotoxicity, lower haemolytic activity and sufficiently high endosomal escape enhancing activity. An embodiment is the saponin derivative according to the invention, wherein the saponin on which the saponin derivative is based is a penta-cyclic triterpene saponin of the 12,13- dehydrooleanane type, preferably the saponin is a monodesmosidic or bidesmosidic penta-cyclic triterpene saponin of the 12,13-dehydrooleanane type. An embodiment is the saponin derivative according to the invention, wherein the saponin on which the saponin derivative is based is a mono-desmosidic or bi-desmosidic triterpene saponin belonging to the type of a 12,13-dehydrooleanane with the aldehyde group in position C-23 and optionally comprising a glucuronic acid group in a carbohydrate substituent at the C-3beta-OH group of the saponin, preferably a bi-desmosidic triterpene saponin belonging to the type of a 12,13- dehydrooleanane with the aldehyde group in position C-23 and comprising a glucuronic acid group in a carbohydrate substituent at the C-3beta-OH group of the saponin. A preferred embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to formula (IV):
Figure imgf000074_0001
wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, X = O, P or S, preferably O; and Y = NR3R4, wherein R3 and R4 independently represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, preferably one of R3 and R4 is H; or
Figure imgf000074_0002
, wherein n and m each are an integer independently selected from 1, 2 or 3; Z = CH2, O, S, P or NR5, and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b,
Figure imgf000074_0003
or an azide moiety according to formula (II)c
Figure imgf000074_0004
(II)c wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6 and W is thiol functional group according to formula (III)
Figure imgf000075_0001
wherein U = SH, NH2 or OH, preferably OH, and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. A preferred embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to formula (IV):
Figure imgf000075_0002
wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, X = O, P or S, preferably O; and
Figure imgf000075_0003
, wherein n and m each are an integer independently selected from 1, 2 or 3; Z = CH2, O, S, P or NR5, preferably O or NR5, and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or a branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b, preferably H or a covalently bound linker or the branched alkynyl or a maleimide moiety according to formula (II)a or formula (II)b,
Figure imgf000075_0004
(II)a (II)b or an azide moiety according to formula (II)c
Figure imgf000076_0001
(II)c wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6 and W is thiol functional group according to formula (III)
Figure imgf000076_0002
wherein U = SH, NH2 or OH, preferably OH, and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2. An embodiment is the saponin derivative according to the invention, wherein the semicarbazone functional group according to formula (I), the linear semicarbazide is according
Figure imgf000076_0003
formula (3) or saponin derivative is according to formula (IV), wherein Y = , wherein n = 1 and m = 1, n = 2 and m = 1, n = 2 and m = 2, n = 3 and m = 2 or n = 3 and m = 3; preferably wherein n = 1 and m = 2, n =2 and m = 2, or n =2 and m =3, more preferably n = 2 and m = 3 and Z is defined according to the previous embodiments. Particular saponin derivatives according to the invention are thus saponin derivatives, wherein n = 1 and m = 1, or n = 2 and m = 1, or n = 2 and m = 2, or n = 3 and m = 2, or n = 3 and m = 3; preferably wherein n = 2 and m = 2. An embodiment is the saponin derivative according to the invention, wherein R1 is selected from H, GlcA-, Glc-, Gal-, Rha-(1→2)-Ara-, Gal-(1→2)-[Xyl-(1→3)]-GlcA-, Glc-(1→2)-[Glc-(1→4)]-GlcA-, Glc-(1→2)-Ara-(1→3)-[Gal-(1→2)]-GlcA-, Xyl-(1→2)-Ara-(1→3)-[Gal-(1→2)]-GlcA-, Glc-(1→3)-Gal-(1→2)-[Xyl-(1→3)]-Glc-(1→4)-Gal-, Rha-(1→2)-Gal-(1→3)-[Glc-(1→2)]-GlcA-, Ara-(1→4)-Rha-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Rha-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Rha-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Ara-(1→4)-Rha-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, and derivatives thereof, preferably R1 is Gal-(1→2)-[Xyl-(1→3)]-GlcA-; and R2 is selected from: H, Glc-, Gal-, Rha-(1→2)-[Xyl-(1→4)]-Rha-, Rha-(1→2)-[Ara-(1→3)-Xyl-(1→4)]-Rha-, Ara-, Xyl-, Xyl-(1→4)-Rha-(1→2)-[R1-(→4)]-Fuc- wherein R1 is 4E-Methoxycinnamic acid, Xyl-(1→4)-Rha-(1→2)-[R2-(→4)]-Fuc- wherein R2 is 4Z-Methoxycinnamic acid, Xyl-(1→4)-[Gal-(1→3)]-Rha-(1→2)-4-OAc-Fuc-, Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-3,4-di-OAc-Fuc-, Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R6-(→4)]-3-OAc-Fuc- wherein R6 is 4E-Methoxycinnamic acid, Glc-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-4-OAc-Fuc-, Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-4-OAc-Fuc-, (Ara- or Xyl-)(1→3)-(Ara- or Xyl-)(1→4)-(Rha- or Fuc-)(1→2)-[4-OAc-(Rha- or Fuc-)(1→4)]-(Rha- or Fuc-), Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Qui-(1→4)]-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-Fuc-, Xyl-(1→4)-[Gal-(1→3)]-Rha-(1→2)-Fuc-, Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-Fuc-, Ara/Xyl-(1→4)-Rha/Fuc-(1→4)-[Glc/Gal-(1→2)]-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R7-(→4)]-Fuc- wherein R7 is 5-O-[5-O-Ara/Api-3,5- dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R8-(→4)]-Fuc- wherein R8 is 5-O-[5-O-Ara/Api-3,5-dihydroxy-6- methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Rha-(1→3)]-4-OAc-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[Rha-(1→3)]-4-OAc-Fuc-, 6-OAc-Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3-OAc-Rha-(1→3)]-Fuc-, Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3-OAc--Rha-(1→3)]-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Qui-(1→4)]-Fuc-, Glc-(1→3)-[Xyl-(1→4)]-Rha-(1→2)-[Qui-(1→4)]-Fuc-, Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3,4-di-OAc-Qui-(1→4)]-Fuc-, Glc-(1→3)-[Xyl-(1→4)]-Rha-(1→2)-Fuc-, 6-OAc-Glc-(1→3)-[Xyl-(1→4)]-Rha-(1→2)-Fuc-, Glc-(1→3)-[Xyl-(1→3)-Xyl-(1→4)]-Rha-(1→2)-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[Rha-(1→3)]-4OAc-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[Rha-(1→3)]-4OAc-Fuc-, Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R9-(→4)]-Fuc- wherein R9 is 5-O-[5-O-Rha- (1→2)-Ara/Api-3,5-dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R10-(→4)]-Fuc- wherein R10 is 5-O-[5-O- Ara/Api-3,5-dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R11-(→4)]-Fuc- wherein R11 is 5-O-[5-O- Ara/Api-3,5-dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R12-(→4)]-Fuc- wherein R12 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R13-(→4)]-Fuc- wherein R13 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R14-(→3)]-Fuc- wherein R14 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R15-(→3)]-Fuc- wherein R15 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid) Glc-(1→3)-[Glc-(1→6)]-Gal-, and derivatives thereof; preferably R2 is selected from: Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3,4-di-OAc-Qui-(1→4)]-Fuc-, Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R12-(→4)]-Fuc- wherein R12 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R13-(→4)]-Fuc- wherein R13 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R14-(→3)]-Fuc- wherein R14 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, and Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R15-(→3)]-Fuc- wherein R15 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, more preferably R2 is Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, most preferably R1 is Gal-(1→2)-[Xyl-(1→3)]-GlcA- and R2 is Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)- [Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-. In preferred saponin derivatives according to the invention, R1 is Gal-(1→2)-[Xyl-(1→3)]-GlcA-; and R2 is selected from: Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3,4-di-OAc-Qui-(1→4)]-Fuc-, Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R12-(→4)]-Fuc- wherein R12 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R13-(→4)]-Fuc- wherein R13 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R14-(→3)]-Fuc- wherein R14 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, and Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R15-(→3)]-Fuc- wherein R15 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, preferably, R1 is Gal-(1→2)-[Xyl-(1→3)]-GlcA- and R2 is Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl- (1→3)-4-OAc-Qui-(1→4)]-Fuc-. Saponin derivatives comprising such a R1 group and such an R2 group are preferably saponin derivatives based on a saponin listed in Table A1, for which endosomal escape enhancing activity has been established and/or predicted based on structural similarity or analogy. An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is a derivative of a saponin selected from the group of saponins consisting of: Quillaja bark saponin, dipsacoside B, saikosaponin A, saikosaponin D, macranthoidin A, esculentoside A, phytolaccagenin, aescinate, AS6.2, NP-005236, AMA-1, AMR, alpha-Hederin, NP-012672, NP- 017777, NP-017778, NP-017774, NP-018110, NP-017772, NP-018109, NP-017888, NP-017889, NP-018108, SA1641, AE X55, NP-017674, NP-017810, AG1, NP-003881, NP-017676, NP- 017677, NP-017706, NP-017705, NP-017773, NP-017775, SA1657, AG2, SO1861, GE1741, SO1542, SO1584, SO1658, SO1674, SO1832, SO1904, SO1862, QS-7, QS1861, QS-7 api, QS1862, QS-17, QS-18, QS-21 A-apio, QS-21 A-xylo, QS-21 B-apio, QS-21 B-xylo, beta-Aescin, Aescin Ia, Teaseed saponin I, Teaseedsaponin J, Assamsaponin F, Digitonin, Primula acid 1 and AS64R, preferably the saponin derivative is selected from the group consisting of a QS-21 derivative, an SO1861 derivative, an SA1641 derivative and an GE1741 derivative, more preferably the saponin derivative is selected from the group consisting of a QS-21 derivative and an SO1861 derivative, most preferably the saponin derivative is an SO1861 derivative. These saponins are essentially saponins displaying endosomal escape enhancing activity as established by the inventors, or that are structurally highly similar to saponins for which the endosomal escape enhancing activity has been established. Structural outline of these saponins is summarized in Table A1. Since SO1861 and SO1832 are about equally active (when endosomal escape enhancing effects are assessed), application of SO1861 and SO1832 in the saponin derivatives and in the saponin conjugates of the invention is equally preferred. Thus, typically, for the saponin derivative according to the invention, the saponin derivative is a derivative of a saponin selected from the group of saponins consisting of: Quillaja bark saponin, dipsacoside B, saikosaponin A, saikosaponin D, macranthoidin A, esculentoside A, phytolaccagenin, aescinate, AS6.2, NP-005236, AMA-1, AMR, alpha-Hederin, NP-012672, NP- 017777, NP-017778, NP-017774, NP-018110, NP-017772, NP-018109, NP-017888, NP-017889, NP-018108, SA1641, AE X55, NP-017674, NP-017810, AG1, NP-003881, NP-017676, NP- 017677, NP-017706, NP-017705, NP-017773, NP-017775, SA1657, AG2, SO1861, GE1741, SO1542, SO1584, SO1658, SO1674, SO1832, SO1904, SO1862, QS-7, QS1861, QS-7 api, QS1862, QS-17, QS-18, QS-21 A-apio, QS-21 A-xylo, QS-21 B-apio, QS-21 B-xylo, beta-Aescin, Aescin Ia, Teaseed saponin I, Teaseedsaponin J, Assamsaponin F, Digitonin, Primula acid 1 and AS64R, preferably the saponin derivative is selected from the group consisting of a QS-21 derivative, an SO1861 derivative, an SA1641 derivative and a GE1741 derivative, more preferably the saponin derivative is selected from the group consisting of a QS-21 derivative and an SO1861 derivative, most preferably the saponin derivative is an SO1861 derivative. As said before, a derivative based on SO1861 and SO1832 is equally preferred. An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is selected from the group consisting of derivatives of: SO1861, SA1657, GE1741, SA1641, QS-21, QS-21A, QS-21 A-api, QS-21 A-xyl, QS-21B, QS-21 B-api, QS-21 B-xyl, QS-7- xyl, QS-7-api, QS-17-api, QS-17-xyl, QS1861, QS1862, Quillajasaponin, Saponinum album, QS- 18, Quil-A, Gyp1, gypsoside A, AG1, AG2, SO1542, SO1584, SO1658, SO1674, SO1832, SO1862, SO1904, stereoisomers thereof and combinations thereof, preferably the saponin derivative is selected from the group consisting of a SO1861 derivative, a GE1741 derivative, a SA1641 derivative, a QS-21 derivative, and a combination thereof, more preferably the saponin derivative is a SO1861 derivative or a QS-21 derivative, most preferably, the saponin derivative is a SO1861 derivative. An embodiment is the saponin derivative of the invention, wherein the saponin on which the saponin derivative is based is any one or more of: a) saponin selected from any one or more of list A: - Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; - Gypsophila elegans saponin mixture, or a saponin isolated from Gypsophila elegans; - Saponinum album saponin mixture, or a saponin isolated from Saponinum album; - Saponaria officinalis saponin mixture, or a saponin isolated from Saponaria officinalis; and - Quillaja bark saponin mixture, or a saponin isolated from Quillaja bark, for example Quil- A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; or b) a saponin comprising a gypsogenin aglycone core structure, selected from list B: SA1641, gypsoside A, NP-017772, NP-017774, NP-017777, NP-017778, NP-018109, NP- 017888, NP-017889, NP-018108, SO1658 and Phytolaccagenin; or c) a saponin comprising a quillaic acid aglycone core structure, selected from list C: AG1856, AG1, AG2, Agrostemmoside E, GE1741, Gypsophila saponin 1 (Gyp1), NP- 017674, NP-017810, NP-003881, NP-017676, NP-017677, NP-017705, NP-017706, NP- 017773, NP-017775, SA1657, Saponarioside B, SO1542, SO1584, SO1674, SO1700, SO1730, SO1772, 10 SO1832, SO1861, SO1862, SO1904, QS-7, QS-7 api, QS-17, QS- 18, QS-21 A-apio, QS-21 A-xylo, QS-21 B-apio and QS-21 B-xylo; preferably, the saponin is any one or more of a saponin selected list B or C, more preferably, a saponin selected from list C. An embodiment is the saponin derivative of the invention, wherein the saponin (on which the saponin derivative is based) is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS-7, SA1641, a saponin isolated from Saponaria officinalis, Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; preferably wherein the saponin is any one or more of QS- 21, SO1832, SO1861, SA1641 and GE1741; more preferably wherein the saponin is QS-21, SO1832 or SO1861; most preferably being SO1861. An embodiment is the saponin derivative of the invention, wherein the saponin (on which the saponin derivative is based) is a saponin isolated from Saponaria officinalis, preferably wherein the saponin is any one or more of Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; more preferably wherein the saponin is any one or more of SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; even more preferably wherein the saponin is any one or more of SO1832, SO1861 and SO1862; even more preferably wherein the saponin is SO1832 and SO1861; most preferably being SO1861. Particularly preferred is a saponin derivative of the invention, wherein the saponin derivative is according to formula (V) (See Figure 2A, Molecule (V); see the detailed outline in the Examples section, here below), formula (VI), formula (VII) (See Figure 1 and Figure 2B, Molecule (VII); see the detailed outline in the Examples section, here below) or formula (VIII) (See Figure 2B, Molecule (VIII); see the detailed outline in the Examples section, here below):
Figure imgf000082_0001
Figure imgf000083_0001
The saponin derivatives according to Molecule (V), Molecule (VII) and/or Molecule (VIII) are preferred, the saponin derivatives according to Molecule (V) and Molecule (VIII) are more preferred. See Figure 1 and 2 and the Examples section, here below. Even more preferred is the saponin derivative according to formula (VIII) or Molecule (VIII). Particularly preferred is a saponin derivative of the invention, wherein the saponin derivative is according to molecule (AA):
Figure imgf000084_0001
, wherein
Figure imgf000084_0003
represents a saponin moiety according to formula (SM):
Figure imgf000084_0002
, wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23. The saponin moiety is for example based on any one of the saponins listed in the embodiments outlined here above and/or in Table A1, and SO1861, SO1832 and QS-21 are preferred, although SO1861 and SO1832 are most preferred. Preferred is a saponin derivative of the invention, wherein the saponin derivative is according to molecule (BB):
Figure imgf000085_0001
, which molecule (BB) is the covalent conjugation product obtained by the covalent conjugation of the saponin derivative according to molecule (AA) outlined here above with the tri-functional linker according to formula (XXI):
Figure imgf000085_0002
(XXI). Also preferred is the saponin derivative according to the invention wherein the saponin derivative is according to molecule (KK):
Figure imgf000086_0001
, wherein
Figure imgf000086_0002
represents a saponin moiety according to formula (SM):
Figure imgf000086_0003
, wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide according to the invention and as outlined here above, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23 according to the invention. Suitable saponins are for example outlined inTable A1. SO1861, SO1832 and QS-21 are preferred, although SO1861 and SO1832 are more preferred. A preferred embodiment is the saponin derivative according to the invention, characterized in that the saponin derivative comprises a single saponin moiety. A preferred embodiment is the saponin derivative according to the invention, characterized in that the saponin derivative comprises more than one saponin moiety, such as 2-64 moieties, preferably 4-32 moieties, more preferably 4- 16 moieties, most preferably 4-8 moieties such as 4 or 8 moieties. Saponin derivatives comprising more than a single saponin moiety, such as a saponin derivative based on a G2 dendron or G3 dendron, comprising four or eight saponin moieties respectively, which are provided with the semicarbazone functional group, provide the advantage of providing higher extent of endosomal escape enhancing activity by a single saponin derivative molecule as compared to a saponin derivative comprising a single saponin moiety. Part of the invention is the saponin derivative according to molecule (JJ):
Figure imgf000087_0001
which molecule (JJ) is the conjugate product of conjugation of N,N'-((9S,19S)-14-(6- aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo-4,11,14,17- tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide first with the saponin derivative according to molecule (KK), as displayed here above, and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido- 3,6,9,12-tetraoxapentadecan-15-oate. Also part of the invention is the saponin derivative according to molecule (QQ):
Figure imgf000088_0001
which molecule (QQ) is the conjugate product of conjugation of (2S)-N-[(1S)-1-{[2-(6-amino-N-{2- [(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate first with the saponin derivative according to the invention and according to molecule (KK) as displayed and described here above, and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido- 3,6,9,12-tetraoxapentadecan-15-oate. An embodiment is the saponin derivative according to the invention, characterized in that the saponin derivative has a molecular weight of less than 2500 g/mol, preferably less than 2300 g/mol, more preferably less than 2150 g/mol. An embodiment is the saponin derivative according to the invention, characterized in that the saponin derivatisation has a molecular weight of less than 400 g/mol, preferably less than 300 g/mol, more preferably less than 270 g/mol. The molecular weight of the saponin derivatisation corresponds to the molecular weight of the saponin derivative exclusive of the aglycone core and the one (for monodesmosidic saponins) or two (for bidesmosidic saponins) glycon (sugar) chains. Pharmaceutical compositions and combinations comprising a saponin derivative An aspect of the invention relates to a first pharmaceutical composition comprising the saponin derivative according to the invention and optionally a pharmaceutically acceptable excipient and/or diluent. An embodiment is the first pharmaceutical composition according to the invention comprising the saponin derivative according to the invention, preferably a pharmaceutically acceptable diluent, and further comprising: ^ a pharmaceutically acceptable salt, preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganese, potassium, sodium, strontium, or zinc salt, preferably NaCl; and/or ^ a pharmaceutically acceptable buffer system, such as a phosphate, a borate, a citrate, a carbonate, a histidine, a lactate, a tromethamine, a gluconate, an aspartate, a glutamate, a tartarate, a succinate, a malate, a fumarate, an acetate and/or a ketoglutarate containing buffer system. An embodiment is the first pharmaceutical composition according to the invention comprising the saponin derivative according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and has a pH within the range of 2-11, preferably within the range of 4-9, more preferably within the range of 6-8. An embodiment is the first pharmaceutical composition according to the invention comprising a saponin derivative according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and wherein the concentration of the saponin derivative is within the range of 10-12 to 1 mol/l, preferably within the range of 10-9 to 0.1 mol/l, more preferably within the range of 10-6 to 0.1 mol/l. Typically, such a first pharmaceutical composition is suitable for use in combination with e.g. an ADC or an AOC. For example, the first pharmaceutical composition is administered to a patient in need of administration of the ADC or AOC, before the ADC or AOC is administered, together with the ADC or AOC, or (shortly) after administration of the ADC or the AOC to the patient in need of such ADC or AOC therapy. For example, the first pharmaceutical composition is mixed with a pharmaceutical composition comprising the ADC or the AOC, and a suitable dose of the mixture obtained is administered to a patient in need of ADC or AOC therapy. According to the invention, the saponin derivative comprised by the first pharmaceutical composition enhances the efficacy and potency of the effector molecule comprised by such an ADC or AOC, when the saponin derivative and the ADC or AOC co-localize inside a target cell such as a tumor cell. Under influence of the saponin derivative, the effector molecule is released into the cytosol of the target cell to a higher extent, compared to contacting the same cells with the same dose of ADC or AOC in the absence of the saponin derivative. Thus, similar efficacy can be obtained at lower ADC or AOC dose when the effector molecule co-localizes inside a target cell together with the saponin derivative of the first pharmaceutical composition, compared to the dose required to achieve the same efficacy in the absence of the saponin derivative inside the cell where the ADC or the AOC comprising the effector molecule is delivered. An embodiment is the first pharmaceutical composition of the invention, wherein the saponin derivative is the saponin derivative according to formula (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) (depicted in Figure 2), the saponin derivative according to formula (VIII) or any combination thereof. Preferred are saponin derivatives as depicted in Figure 1, Figure 2A and 2B: Molecule (V), Molecule (VII) and Molecule (VIII) (see also the detailed outline of the synthesis of these saponin derivatives in the Examples section, here below). An aspect of the invention relates to a first pharmaceutical combination comprising: (a) the first pharmaceutical composition of the invention; and (b) a second pharmaceutical composition comprising a conjugate of a cell-surface molecule binding-molecule and an effector moiety, wherein the cell-surface molecule binding-molecule is a proteinaceous molecule such as an antibody, and optionally comprising a pharmaceutically acceptable excipient and/or diluent. An aspect of the invention relates to a first pharmaceutical combination comprising: (a) the first pharmaceutical composition of the invention; and (b) a second pharmaceutical composition comprising any one or more of: a conjugate of a cell- surface molecule binding-molecule and an effector moiety, an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody- oligonucleotide conjugate and a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent. Such a receptor ligand can be a receptor ligand known in the art of cell-targeting therapy, such as EGF. Typically, such a receptor ligand targets a receptor on a diseased cell such as a tumor cell or an autoreactive immune cell (autoimmune cell) such as in rheumatoid arthritis. Typically, such a receptor ligand is a proteinaceous molecule such as a peptide or a protein, although non-proteinaceous receptor ligands known in the art are equally suitable. Such receptor ligands can also be selected from molecules such as adnectins, anticalins, affibodies, etc., etc. The common denominator for the receptor ligands is their specificity for an epitope on a target cell, for targeted delivery of an effector moiety bound to the receptor ligand, reminiscent to the targeted delivery of effector moieties such as toxins, enzymes, oligonucleotides, drug molecules, etc., linked to e.g. an antibody or a single domain antibody, etc. Suitable cell-surface molecule binding- molecules are proteinaceous molecules such as antibodies, sdAb, etc., and non-proteinaceous molecules, suitable for targeting a selected cell (type) and therewith suitable for bringing a saponin derivative of the invention and/or a payload, effector molecule, effector moiety such as a drug, toxin, oligonucleotide, enzyme, in close proximity of the target cell surface to which the cell-surface molecule binding-molecule can bind. Typically, the cell-surface molecule is a receptor. The binding of the cell-surface molecule binding-molecule to the target cell is followed by transfer of the saponin derivate and/or the payload, effector molecule, effector moiety, to the endosome of the cell to which the cell-surface molecule binding-molecule is bound. An aspect of the invention relates to a therapeutic combination comprising: ^ the first pharmaceutical composition of the invention; and ^ a second pharmaceutical composition comprising any one or more of an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent. An aspect of the invention relates to a third pharmaceutical composition comprising the saponin derivative of the invention and further comprising a conjugate of a cell-surface molecule binding-molecule and an effector moiety, wherein the cell-surface molecule binding-molecule is a proteinaceous molecule such as an antibody, and optionally comprising a pharmaceutically acceptable excipient and/or diluent. An aspect of the invention relates to a third pharmaceutical composition comprising the saponin derivative of the invention and further comprising any one or more of: a conjugate of a cell- surface molecule binding-molecule and an effector moiety, an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody- oligonucleotide conjugate and a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent. An aspect of the invention relates to a third pharmaceutical composition comprising the saponin derivative of the invention and further comprising any one or more of: an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-nucleic acid conjugate or a receptor-ligand – nucleic acid conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent. An embodiment is the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, wherein the second pharmaceutical composition or the third pharmaceutical composition comprises any one or more of an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, wherein the drug is for example a toxin such as saporin or dianthin, and wherein the oligonucleotide is for example an AON such as an siRNA or a BNA, for example for gene silencing of apolipoprotein B (apoB) or HSP27. An embodiment is the first pharmaceutical combination comprising the second pharmaceutical composition of the invention, or the third pharmaceutical composition of the invention, wherein the second pharmaceutical composition or the third pharmaceutical composition comprises any one or more of an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody- oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, wherein preferably the toxin is a protein toxin. An embodiment is the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, wherein the saponin derivative is a saponin derivative selected from the group consisting of derivatives of: SO1861, SA1657, GE1741, SA1641, QS-21, QS-21A, QS-21 A-api, QS-21 A-xyl, QS-21B, QS-21 B-api, QS-21 B-xyl, QS-7-xyl, QS-7-api, QS- 17-api, QS-17-xyl, QS1861, QS1862, Quillajasaponin, Saponinum album, QS-18, Quil-A, Gyp1, gypsoside A, AG1, AG2, SO1542, SO1584, SO1658, SO1674, SO1832, SO1862, SO1904, stereoisomers thereof and combinations thereof, preferably the saponin derivative is selected from the group consisting of an SO1861 derivative, a GE1741 derivative, an SA1641 derivative, a QS- 21 derivative, and a combination thereof, more preferably the saponin derivative is an SO1861 derivative or a QS21 derivative, more preferably, the saponin derivative is an SO1861 derivative, even more preferably the saponin derivative is the saponin derivative according to formula (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII), the saponin derivative according to formula (VIII) or any combination thereof. Also preferred is the saponin derivate according to molecule (AA), molecule (BB), molecule (KK), molecule (JJ) and molecule (QQ). Even more preferred is the saponin derivative according to any one or more of formula (VII) or Molecule (VII), formula (V) or Molecule (V), and formula (VIII) or Molecule (VIII). Even more preferred is the saponin derivative according to formula (VIII) or Molecule (VIII). An embodiment is the third pharmaceutical composition according to the invention comprising a saponin derivative according to the invention, and further comprising preferably a pharmaceutically acceptable diluent, and further comprising: ^ a pharmaceutically acceptable salt, preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganese, potassium, sodium, strontium, or zinc salt, preferably NaCl; and/or ^ a pharmaceutically acceptable buffer system, such as a phosphate, a borate, a citrate, a carbonate, a histidine, a lactate, a tromethamine, a gluconate, an aspartate, a glutamate, a tartarate, a succinate, a malate, a fumarate, an acetate and/or a ketoglutarate containing buffer system. An embodiment is the third pharmaceutical composition according to the invention comprising a saponin derivative according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and has a pH within the range of 2-11, preferably within the range of 4-9, more preferably within the range of 6-8. An embodiment is the third pharmaceutical composition according to the invention comprising a saponin derivative according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and wherein the concentration of the saponin derivative is within the range of 10-12 to 1 mol/l, preferably within the range of 10-9 to 0.1 mol/l, more preferably within the range of 10-6 to 0.1 mol/l. Preferred is the first pharmaceutical combination comprising the second pharmaceutical composition or the third pharmaceutical composition according to the invention, wherein the second pharmaceutical composition or the third pharmaceutical composition comprise an antibody-toxin conjugate, an antibody-drug conjugate, or an antibody-oligonucleotide conjugate, wherein the antibody is a cell-surface molecule targeting molecule which can bind to a tumor-cell surface molecule, preferably to a tumor-cell receptor such as a tumor-cell specific receptor, more preferably to a receptor selected from CD71, CD63, CA125, EpCAM(17-1A), CD52, CEA, CD44v6, FAP, EGF- IR, integrin, syndecan-1, vascular integrin alpha-V beta-3, HER2, EGFR, CD20, CD22, Folate receptor 1, CD146, CD56, CD19, CD138, CD27L receptor, PSMA, CanAg, integrin-alphaV, CA6, CD33, mesothelin, Cripto, CD3, CD30, CD239, CD70, CD123, CD352, DLL3, CD25, ephrinA4, MUC1, Trop2, CEACAM5, CEACAM6, HER3, CD74, PTK7, Notch3, FGF2, C4.4A, FLT3, CD38, FGFR3, CD7, PD-L1, CTLA4, CD52, PDGFRA, VEGFR1, VEGFR2, preferably selected from CD71, HER2 and EGFR, more preferably wherein the antibody is a whole antibody or at least a cell-surface molecule binding fragment or -domain thereof, and preferably wherein the antibody comprises or consists of any one of cetuximab, daratumumab, gemtuzumab, trastuzumab, panitumumab, brentuximab, inotuzumab, moxetumomab, polatuzumab, obinutuzumab, OKT-9 anti- CD71 monoclonal antibody of the IgG type, pertuzumab, rituximab, ofatumumab, Herceptin, alemtuzumab, pinatuzumab, OKT-10 anti-CD38 monoclonal antibody, an antibody of Table A2, preferably cetuximab or trastuzumab or OKT-9, or at least one cell-surface molecule binding fragment or -domain thereof. Such an antibody can also be a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, a string of single-domain antibodies, a binding molecule comprising VHH, a binding molecule comprising VH, etc. Preferred is the first pharmaceutical combination comprising the second pharmaceutical composition or the third pharmaceutical composition according to the invention wherein the effector moiety is an oligonucleotide comprising or consisting of any one or more of a nucleic acid and a xeno nucleic acid, preferably selected from any one or more of a vector, a gene, a cell suicide inducing transgene, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), anti-sense oligonucleotide (ASO, AON), short interfering RNA (siRNA), microRNA (miRNA), DNA aptamer, RNA aptamer, mRNA, mini-circle DNA, peptide nucleic acid (PNA), phosphoramidate morpholino oligomer (PMO), locked nucleic acid (LNA), bridged nucleic acid (BNA), 2’-deoxy-2’-fluoroarabino nucleic acid (FANA), 2’-O-methoxyethyl-RNA (MOE), 2'-O,4'-aminoethylene bridged nucleic acid, 3’-fluoro hexitol nucleic acid (FHNA), a plasmid, glycol nucleic acid (GNA) and threose nucleic acid (TNA), or a derivative thereof, more preferably a BNA or an siRNA, for example a BNA for silencing HSP27 protein expression or apoB protein expression. Also preferred is the first pharmaceutical combination comprising the second pharmaceutical composition or the third pharmaceutical composition according to the invention wherein the effector moiety comprises or consists of at least one proteinaceous molecule, preferably selected from any one or more of a peptide, a protein, an enzyme such as urease and Cre-recombinase, a ribosome-inactivating protein, a proteinaceous toxin selected from any one or more of a viral toxin such as apoptin; a bacterial toxin such as Shiga toxin, Shiga-like toxin, Pseudomonas aeruginosa exotoxin (PE) or exotoxin A of PE, full-length or truncated diphtheria toxin (DT), cholera toxin; a fungal toxin such as alpha-sarcin; a plant toxin including ribosome- inactivating proteins and the A chain of type 2 ribosome-inactivating proteins such as dianthin e.g. dianthin-30 or dianthin-32, saporin e.g. saporin-S3 or saporin-S6, bouganin or de-immunized derivative debouganin of bouganin, shiga-like toxin A, pokeweed antiviral protein, ricin, ricin A chain, modeccin, modeccin A chain, abrin, abrin A chain, volkensin, volkensin A chain, viscumin, viscumin A chain; or an animal or human toxin such as frog RNase, or granzyme B or angiogenin from humans, or any fragment or derivative thereof; preferably the protein toxin is dianthin and/or saporin. An embodiment is the first pharmaceutical combination comprising the second pharmaceutical composition of the invention or the third pharmaceutical composition of the invention, wherein the second pharmaceutical composition or the third pharmaceutical composition comprises any one or more of an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody- oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, wherein the drug is for example a toxin such as saporin and dianthin, and wherein the oligonucleotide is for example an AON such as an siRNA or a BNA, for example for gene silencing of apolipoprotein B (apoB) or HSP27. Preferred is the first pharmaceutical combination comprising the first pharmaceutical composition of the invention, or the third pharmaceutical composition of the invention, wherein the saponin derivative is any one or more of the saponin derivatives according to the invention. An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use as a medicament. An aspect of the invention relates to the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use as a medicament. An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination comprising the first pharmaceutical composition of the invention, or the third pharmaceutical composition of the invention, for use as a medicament. In preferred embodiments there is provided the first pharmaceutical composition of the invention wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof; the first pharmaceutical combination of the invention wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof, or the third pharmaceutical composition of the invention wherein the saponin derivative comprises, preferably consists the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof, for use as a medicament. An aspect of the invention is the provision of the saponin derivative as described herein, preferably the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof, for use as a medicament. An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cancer or an auto-immune disease. An aspect of the invention relates to the first pharmaceutical combination of the invention or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cancer or an auto-immune disease. An aspect of the invention relates to the first pharmaceutical composition of the invention, the first pharmaceutical combination of the invention, or the third pharmaceutical composition of the invention, for use in the treatment or prophylaxis of a cancer or an auto-immune disease. In preferred embodiments there is provided the first pharmaceutical composition of the invention wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof; the first pharmaceutical combination of the invention wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof; or the third pharmaceutical composition of the invention wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Moelcule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof, for use in the treatment or prophylaxis of a cancer or an auto-immune disease. An aspect of the invention relates to the first pharmaceutical combination, the second pharmaceutical combination, or the third pharmaceutical composition, for use according to the invention, preferably in a human patient, wherein the first cell surface molecule and the third cell surface molecule are CD71 and/or the second cell surface molecule is CD71, and/or the first proteinaceous molecule comprised by the saponin conjugate and the third proteinaceous molecule are a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the second proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and/or the effector moiety is an oligonucleotide, preferably, the first, second and third cell surface molecule is CD71, the first, second and third proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and the effector moiety is an oligonucleotide. An aspect of the invention relates to an antibody-drug conjugate, antibody-oligonucleotide conjugate, ligand-drug conjugate or ligand-oligonucleotide conjugate, comprising the saponin conjugate of the invention and an effector moiety according to the invention, preferably an antibody- oligonucleotide conjugate comprising the saponin conjugate of the invention and an effector moiety according to the invention. An aspect of the invention relates to the antibody-drug conjugate, antibody-oligonucleotide conjugate, ligand-drug conjugate or ligand-oligonucleotide conjugate of the invention, preferably the antibody-oligonucleotide conjugate of the invention, for use as a medicament. An aspect of the invention relates to the antibody-drug conjugate, antibody-oligonucleotide conjugate, ligand-drug conjugate or ligand-oligonucleotide conjugate of the invention, preferably the antibody-oligonucleotide conjugate of the invention, for use in the treatment or prevention of a disease or health problem related to presence of the diseased cell according to the invention, for use in the treatment or prevention of a disease or health problem related to the presence of the aberrant cell according to the invention, for use in the treatment or prevention of a cancer, for use in the treatment or prevention of an autoimmune disease such as rheumatoid arthritis, preferably in a human patient, wherein preferably, the first, second and third cell surface molecule is CD71, the first, second and third proteinaceous molecule is a monoclonal antibody capable of binding to CD71 or at least one sdAb capable of binding to CD71, and the effector moiety is an oligonucleotide. Method for delivering an effector molecule inside a cell, using a saponin derivative or a saponin conjugate An aspect of the invention relates to an in vitro or ex vivo method for transferring a molecule from outside a cell to inside said cell, preferably into the cytosol of said cell, comprising the steps of: a) providing a cell; b) providing the molecule for transferring from outside the cell into the cell provided in step a); c) providing a saponin derivative according to the invention; d) contacting the cell of step a) in vitro or ex vivo with the molecule of step b) and the saponin derivative of step c), therewith establishing the transfer of the molecule from outside the cell into said cell. An embodiment is the method of the invention, wherein the cell is a human cell such as a T- cell, an NK-cell, a tumor cell, and/or wherein the molecule of step b) is any one of: an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-oligonucleotide conjugate or a receptor- ligand – oligonucleotide conjugate, wherein the drug is for example a toxin and wherein the oligonucleotide is for example an AON such as an siRNA or a BNA, and/or wherein the saponin derivative is selected from the group consisting of derivatives of: SO1861, SA1657, GE1741, SA1641, QS-21, QS-21A, QS-21 A-api, QS-21 A-xyl, QS-21B, QS-21 B-api, QS-21 B-xyl, QS-7- xyl, QS-7-api, QS-17-api, QS-17-xyl, QS1861, QS1862, Quillajasaponin, Saponinum album, QS- 18, Quil-A, Gyp1, gypsoside A, AG1, AG2, SO1542, SO1584, SO1658, SO1674, SO1832, SO1862, SO1904, stereoisomers thereof and combinations thereof, preferably the saponin derivative is selected from the group consisting of an SO1861 derivative, a GE1741 derivative, an SA1641 derivative, a QS-21 derivative, and a combination thereof, more preferably the saponin derivative is an SO1861 derivative or a QS-21 derivative, most preferably, the saponin derivative is an SO1861 derivative; or wherein the saponin derivative is according to any one of formula (V) or Molecule (V), formula (VI), formula (VII) or Molecule (VII) and formula (VIII) or Molecule (VIII), preferably the saponin derivative is according to formula (V) or Molecule (V) or formula (VIII) or Molecule (VIII). In particular embodiments the in vitro or ex vivo method for transferring a molecule from outside a cell to inside said cell, preferably into the cytosol of said cell as described herein is provided wherein the saponin derivative comprises, preferably consists of the saponin derivative according to formula (V) or Molecule (V), the saponin derivative according to formula (VI), the saponin derivative according to formula (VII) or Molecule (VII), the saponin derivative according to formula (VIII) or Molecule (VIII) or any combination thereof. Alternatively, a saponin conjugate of the invention (see also here below for an outline of such saponin conjugate) comprising at least one saponin moiety, a cell surface-receptor targeting ligand (cell-targeting ligand) such as an antibody or a binding fragment or domain thereof, or one or more GalNAc moieties, and optionally an effector moiety such as an oligonucleotide, is applied in the method of the invention. The conjugate without an effector moiety is applied together with an effector moiety or a further conjugate of an effector moiety and a cell surface-receptor targeting ligand (cell-targeting ligand) such as an antibody or a binding fragment or domain thereof, or one or more GalNAc moieties. The conjugate comprising saponin and an effector moiety, in addition to a cell surface-receptor targeting ligand (cell-targeting ligand) such as an antibody or a binding fragment or domain thereof, or one or more GalNAc moieties, is also applied in the method (such a conjugate is also referred to as a 1-component conjugate). An embodiment is the method of the invention, wherein the saponin conjugate is selected from any one of the saponin conjugates of the invention, including the 1-component conjugate. It is preferred that the cell-targeting ligand is an antibody such as a monoclonal antibody or at least an sdAb, capable of binding to CD71. It is preferred that the cell with which the method is applied (over)expresses CD71. It is preferred that the molecule selected for transferring into the selected cell by applying the method, is an oligonucleotide according to the invention. Preferably, the saponin on which the saponin derivative comprised by the saponin conjugate is based, is selected from SO1861, SO1832 and QS-21, preferably SO1861 and SO1832, more preferably SO1861. Saponin conjugate based on the saponin derivatives An aspect of the invention relates to a saponin conjugate comprising a cell-surface molecule binding-molecule (also referred to as: cell surface-receptor targeting ligand and cell-targeting ligand) such as a first proteinaceous molecule (‘proteinaceous molecule 1’) that is covalently bound to the saponin derivative according to the invention, i.e. covalently linked to the saponin derivative. The cell-surface molecule binding-molecule is covalently bound to the derivatisation in the saponin derivative, i.e. the derivatised aldehyde functional group of the saponin on which the saponin derivative is based, i.e. through (via) a linker. The cell-surface molecule binding-molecule typically is a protein, such as an antibody or a binding fragment thereof, or a single-domain antibody (sdAb) or a binding molecule comprising a sdAb. An embodiment is the saponin derivative according to the invention, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (IX)
Figure imgf000098_0001
wherein n and m each are an integer independently selected from 1, 2, or 3; o is an integer selected from 0-10, preferably 2-7, more preferably 4-6. An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to molecule (KK): , wherein
Figure imgf000098_0002
Figure imgf000098_0003
represents a saponin moiety according to formula (SM):
Figure imgf000099_0001
, wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide according to the invention, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23 according to the invention. Examples of such saponins are depicted in Table A1. An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to formula (VII) (or Molecule (VII):
Figure imgf000099_0002
(VII). An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to molecule (AA):
Figure imgf000100_0001
, wherein
Figure imgf000100_0002
represents a saponin moiety according to formula (SM):
Figure imgf000100_0003
, wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide according to the invention, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23 according to the invention. Preferred saponins are for example tabulated in Table A1. An embodiment is the saponin conjugate of the invention, wherein the saponin comprised by the conjugate is any one or more of: a) saponin selected from any one or more of list A: - Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; - Gypsophila elegans saponin mixture, or a saponin isolated from Gypsophila elegans; - Saponinum album saponin mixture, or a saponin isolated from Saponinum album; - Saponaria officinalis saponin mixture, or a saponin isolated from Saponaria officinalis; and - Quillaja bark saponin mixture, or a saponin isolated from Quillaja bark, for example Quil- A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; or b) a saponin comprising a gypsogenin aglycone core structure, selected from list B: SA1641, gypsoside A, NP-017772, NP-017774, NP-017777, NP-017778, NP-018109, NP- 017888, NP-017889, NP-018108, SO1658 and Phytolaccagenin; or c) a saponin comprising a quillaic acid aglycone core structure, selected from list C: AG1856, AG1, AG2, Agrostemmoside E, GE1741, Gypsophila saponin 1 (Gyp1), NP- 017674, NP-017810, NP-003881, NP-017676, NP-017677, NP-017705, NP-017706, NP- 017773, NP-017775, SA1657, Saponarioside B, SO1542, SO1584, SO1674, SO1700, SO1730, SO1772, 10 SO1832, SO1861, SO1862, SO1904, QS-7, QS-7 api, QS-17, QS- 18, QS-21 A-apio, QS-21 A-xylo, QS-21 B-apio and QS-21 B-xylo; preferably, the saponin is any one or more of a saponin selected list B or C, more preferably, a saponin selected from list C. An embodiment is the saponin conjugate of the invention, wherein the saponin is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS- 7, SA1641, a saponin isolated from Saponaria officinalis, Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; preferably wherein the saponin is any one or more of QS-21, SO1832, SO1861, SA1641 and GE1741; more preferably wherein the saponin is QS-21, SO1832 or SO1861; most preferably being SO1861. An embodiment is the saponin conjugate of the invention, wherein the saponin is a saponin isolated from Saponaria officinalis, preferably wherein the saponin is any one or more of Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; more preferably wherein the saponin is any one or more of SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; even more preferably wherein the saponin is any one or more of SO1832, SO1861 and SO1862; even more preferably wherein the saponin is SO1832 and SO1861; most preferably being SO1861. An embodiment is the saponin derivative of the invention and/or the saponin conjugate of the invention based on the saponin derivative of the invention, wherein the at least one saponin is covalently bound to a tri-functional linker. A preferred saponin derivative of the invention and/or a saponin conjugate of the invention is a derivative or a conjugate, wherein the at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties, is/are covalently bound via a trifunctional linker. An example of a trifunctional linker that is suitable for incorporation into a saponin derivative or saponin conjugate of the invention is the trifunctional linker represented by formula (XXI):
Figure imgf000102_0001
(XXI). An embodiment is the saponin conjugate of the invention and/or the saponin derivative of the invention, wherein a trifunctional linker, such as the trifunctional linker represented by formula (XXI), is covalently bound to one or more saponin moieties via a first arm of the linker, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties, and, when the saponin conjugate is considered, optionally and preferably also covalently bound to at least one GalNAc moiety, preferably 1-4 GalNAc moieties, more preferably 3 GalNAc moieties, via a second arm of the linker, and, when the saponin conjugate is considered, optionally and preferably also covalently bound to an effector moiety, preferably an oligonucleotide, preferably an AON such as a BNA or an siRNA, via a third arm of the trifunctional linker. Preferred is the saponin conjugate of the invention, wherein the at least one GalNAc moiety, preferably three GalNAc moieties, the at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties and preferably 1, 4 or 8 saponin moieties, and the oligonucleotide are covalently bound via a tri-functional linker, preferably with each of the GalNAc moiety or GalNAc moieties, the saponin or the saponin moieties and the oligonucleotide covalently bound to a separate arm of the tri-functional linker. An embodiment is the saponin derivative of the invention or the saponin conjugate of the invention based on the saponin derivative, comprising one saponin moiety. An embodiment is the saponin derivative of the invention, wherein the at least one saponin is covalently bound to a tri-functional linker. A preferred saponin conjugate comprises at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties, covalently bound to a trifunctional linker. An example of a trifunctional linker that is suitable for incorporation into a saponin conjugate of the invention is the trifunctional linker represented by formula (XXI). An embodiment is the saponin conjugate of the invention, wherein the conjugate comprises at least one GalNAc moiety, at least one saponin and an oligonucleotide, which are covalently bound to each other via a tri-functional linker, preferably with each of the GalNAc moiety, the saponin and the oligonucleotide covalently bound to a separate arm of the tri-functional linker. A preferred saponin conjugate of the invention based on the saponin derivative of the invention is a saponin conjugate, wherein the at least one GalNAc moiety, preferably three GalNAc moieties, at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties, and the oligonucleotide are covalently bound via a trifunctional linker, preferably with each of the GalNAc moiety or GalNAc moieties, the saponin or more than one saponin moieties and the oligonucleotide covalently bound to a separate arm of the trifunctional linker. An example of a trifunctional linker that is suitable for incorporation into a saponin conjugate of the invention is the trifunctional linker represented by formula (XXI). An embodiment is the saponin conjugate of the invention based on the saponin derivative of the invention, comprising at least one saponin covalently linked to a ligand for asialoglycoprotein receptor (ASGPR), wherein the ligand for ASGPR comprises at least one N-acetylgalactosamine (GalNAc) moiety, preferably three or four GalNAc moieties, more preferably three GalNAc moieties, more preferably the ligand for ASGPR comprises or consists of (GalNAc)3Tris, and further covalently linked to an oligonucleotide, wherein the at least one saponin is a monodesmosidic or bidesmosidic penta-cyclic triterpene saponin of the 12,13-dehydrooleanane type, preferably with an aldehyde function in position C-23 of the aglycone core structure of the saponin, wherein the oligonucleotide conjugate comprises 1-16 saponin moieties, preferably 1-8 saponin moieties, more preferably 1 saponin moiety, 4 saponin moieties or 8 saponin moieties. An embodiment is the oligonucleotide conjugate of the invention, wherein the at least one GalNAc moiety, preferably three GalNAc moieties, the at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 1, 4 or 8 saponin moieties, and the oligonucleotide are covalently bound via a tri-functional linker, preferably with each of the GalNAc moiety or moieties, the saponin or saponin moieties and the oligonucleotide covalently bound to a separate arm of the tri-functional linker. An embodiment is the oligonucleotide conjugate of the invention, comprising one saponin moiety, 4 saponin moieties or 8 saponin moieties. An embodiment is the oligonucleotide conjugate of the invention, wherein the at least one saponin moiety is linked via a hydrazone bond or via a semicarbazone bond. The at least one saponin is preferably covalently bound in the oligonucleotide conjugate via a semicarbazone bond. Such a semicarbazone bond (with a linker) is for example formed involving the aldehyde group at the C-23 atom of the quillaic acid aglycone core structure of the saponin or of the gypsogenin aglycone core structure of the saponin (see Table A1 for examples of saponins of these types). Notably, such saponin conjugates of the invention are formed upon conjugation of e.g. one or more GalNAc moieties and/or an oligonucleotide, with a saponin derivative of the invention. An aspect of the invention relates to a saponin conjugate based on a saponin derivative according to the invention, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (IX)
Figure imgf000104_0001
wherein n and m each are an integer independently selected from 1, 2, or 3; o is an integer selected from 0-10, preferably 2-7, more preferably 4-6; and wherein the maleimide functional group is further transformed into a thioether bond through reaction with a first proteinaceous molecule (‘proteinaceous molecule 1’) comprising a thiol functional group according to formula (X)
Figure imgf000104_0003
The saponin derivatives, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (IX)
Figure imgf000104_0002
wherein n and m each are an integer independently selected from 1, 2, or 3; and o is an integer selected from 0-10, preferably 2-7, more preferably 4-6; are suitable for application as a precursor for a conjugation reaction with a further molecule comprising a free sulfhydryl group. The maleimide functional group of the saponin derivative according to formula (IX) can form a thio-ether bond with such a free sulfhydryl group. For example, the saponin derivative according to formula (IX) can be covalently coupled to a peptide or a protein which comprises a free sulfhydryl group such as a cysteine with a free sulfhydryl group. Such a protein is for example an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, for example camelid VH, or a ligand for a cell- surface molecule such as a receptor such as EGF and a cytokine. Application of the saponin derivative according to formula (IX) in a coupling reaction with e.g. an antibody that comprises a free sulfhydryl group, provides a conjugate for targeted delivery of the saponin to and inside a cell, when the antibody (or the binding domain or fragment thereof) is an antibody for specific binding to a target cell surface molecule such as a receptor, e.g. as present on a tumor cell. Preferably, the saponin derivative is coupled to an antibody or VHH capable of binding to a tumor-cell specific surface molecule such as a receptor, e.g. HER2, EGFR, CD71, preferably CD71. It will be appreciated by the skilled person that since the saponin conjugate of the invention comprises (is based on) the saponin derivative according to the invention, all embodiments referring to the saponin derivative applies mutatis mutandis to the saponin conjugate. That is to say, the saponin conjugates of the invention are based on the saponin derivatives according to the invention, detailed here above. A preferred embodiment is the saponin conjugate according to the invention, wherein the saponin conjugate is according to formula (XI)
Figure imgf000105_0001
wherein R1 and R2 are as defined in any one of claims 1-10; n and m each are an integer independently selected from 1, 2 or 3; and o is an integer selected from 0-10, preferably 2-7, more preferably 4-6. A preferred embodiment is the saponin conjugate according to the invention, wherein the semicarbazone functional group according to formula (IX) or the saponin conjugate is according to formula (XI), wherein n = 1 and m = 1, n = 2 and m = 1, n = 2 and m = 2, n = 3 and m = 2, n = 3 and m = 3; preferably wherein n = 1 and m= 2, n = 2 and m = 2, or n =2 and m =3; more preferably wherein n = 2 and m = 2. A highly preferred embodiment is the saponin conjugate according to to formula (XII)
Figure imgf000106_0001
(XII). An aspect of the invention relates to the saponin derivative of the invention, comprising one saponin moiety, and/or to the saponin conjugate of the invention, comprising one saponin moiety. Preferably, the at least one saponin (four saponin derivative moieties for the saponin conjugate according to formula (XII)a (see below), eight saponin derivative moieties for the saponin conjugate according to formula (XII)b) (see below) on which the saponin derivative comprised by the saponin conjugate is based, is any one or more of a saponin selected from list B or C, more preferably from list C. Preferably, the saponin is SO1861 or SO1832, more preferably SO1861. Figure 7B displays a typical example of a saponin conjugate according to the formula (XII)a. The Proteinaceous molecule 1 is here an antibody, preferably a human anti-CD71 antibody. Four G2 dendrons each comprising four copies of a derivative of SO1861 comprising the semicarbazone functional group, are linked to Cysteine residues of the antibody, via a linker. Figure 8B displays a typical example of a saponin conjugate according to the formula (XII)b. The Proteinaceous molecule 1 is here an antibody, preferably a human anti-CD71 antibody. Two G3 dendrons each comprising eight copies of a derivative of SO1861 comprising the semicarbazone functional group, are linked to Cysteine residues of the antibody, via a linker. Preferably, the first proteinaceous molecule (the proteinaceous molecule 1) is a monoclonal antibody or a binding fragment or binding domain thereof, preferably an anti-CD71-antibody or at least one single domain antibody (sdAb) capable of binding to CD71, wherein the sdAb preferably is a VHH domain. Preferably, the proteinaceous molecule 1 is an antibody; preferably an anti-CD71 antibody or at least one sdAb capable of binding to CD71. Preferably, the saponin is SO1861 or SO1832. Preferably, the saponin derivative moieties comprised by the saponin conjugate are the same. When the first proteinaceous molecule (proteinaceous molecule 1) comprised by the saponin conjugate is an antibody, the saponin conjugate comprises preferably 1 or 2 conjugated copies of the dendron-(saponin)4-maleimide2, for which dendron-(saponin)4-maleimide2 as an example dendron-(SO1861)4-maleimide2 is displayed in Figure 4H. More preferred is a single conjugated copy of the dendron-(saponin)4-maleimide2 per antibody molecule. Preferably, the saponin is SO1861 or SO1832, more preferably SO1861. An embodiment is the saponin conjugate of the invention, wherein the saponin conjugate is according to formula (XII)a
Figure imgf000108_0001
Preferably, the proteinaceous molecule 1 is an antibody; preferably an anti-CD71 antibody or at least one sdAb capable of binding to CD71. Preferably, the saponin is SO1861 or SO1832. Preferably, the saponin derivative moieties comprised by the saponin conjugate are the same. When the first proteinaceous molecule (proteinaceous molecule 1) comprised by the saponin conjugate is an antibody, the saponin conjugate comprises preferably 1 or 2 conjugated copies of the dendron-(saponin)8-maleimide1, for which dendron-(saponin)8-maleimide2 as an example dendron-(SO1861)8-maleimide2 is displayed in Figure 5H. More preferred is a single conjugated copy of the dendron-(saponin)8-maleimide2 per antibody molecule. Preferably, the saponin is SO1861 or SO1832, more preferably SO1861. An embodiment is the saponin conjugate of the invention, wherein the saponin conjugate is according to formula (XII)b
Figure imgf000110_0001
An embodiment is the saponin conjugate according to formula (SapCon1) (for which an example based on SO1861 is referred to as “mAB-SC-SO1861(DAR4)” in Fig.6):
Figure imgf000111_0001
(SapCon1) , wherein the saponin derivative comprised by the saponin conjugate is preferably based on a) saponin selected from any one or more of list A: Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; Saponinum album saponin mixture, or a saponin isolated from Saponinum album; Saponaria officinalis saponin mixture, or a saponin isolated from Saponaria officinalis; and Quillaja bark saponin mixture, or a saponin isolated from Quillaja bark, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; or b) a saponin comprising a gypsogenin aglycone core structure, selected from list B: SA1641, gypsoside A, NP-017772, NP-017774, NP-017777, NP-017778, NP-018109, NP- 017888, NP-017889, NP-018108, SO1658 and Phytolaccagenin; or c) a saponin comprising a quillaic acid aglycone core structure, selected from list C: AG1856, AG1, AG2, Agrostemmoside E, GE1741, Gypsophila saponin 1 (Gyp1), NP- 017674, NP-017810, NP-003881, NP-017676, NP-017677, NP-017705, NP-017706, NP-017773, NP-017775, SA1657, Saponarioside B, SO1542, SO1584, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862, SO1904, QS1861, QS1862, QS-7, QS-7 api, QS-17, QS-18, QS-21 A- apio, QS-21 A-xylo, QS-21 B-apio and QS-21 B-xylo, wherein the first proteinaceous molecule of the saponin conjugate is an antibody, such as an anti-CD71 antibody. The saponin conjugate according to formula (SapCon1) comprises four covalently bound saponin derivatives comprising a semicarbazone functional group. Preferably, the four saponins on which the saponin derivatives are based, are the same. Preferably, the at least one saponin (here, four saponin copies) on which the saponin derivative comprised by the saponin conjugate is based, is any one or more of a saponin selected from list B or C, more preferably from list C. Preferably, the saponin is SO1861 or SO1832, more preferably SO1861. Figure 6 displays an example of a saponin conjugate according to the formula (SapCon1): four copies of a saponin derivative based on SO1861 comprise the semicarbazone functional group and are linked, via a linker, to Cysteine residues of the monoclonal antibody, typically anti-CD71 antibody. An embodiment is the saponin conjugate according to the invention, wherein the proteinaceous molecule 1 comprises a same first binding site for binding to a first epitope of a first cell-surface molecule. Preferably, in the saponin conjugate according to the invention, the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule. An embodiment is the saponin conjugate according to the invention, wherein the first binding site of the proteinaceous molecule 1 is selected from any one or more of cell-surface molecule binding-molecules: an amino acid, a peptide, a protein, an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, for example camelid VH, or a ligand for a cell-surface molecule such as a receptor such as EGF and a cytokine, an adnectin, an affibody, an anticalin, or binding molecules comprising one or more of any of these cell-surface molecule binding-molecules. An embodiment is the saponin conjugate according to the invention, wherein the first binding site of the proteinaceous molecule 1 is or comprises a single-domain antibody (sdAb), preferably VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VHH domain such as derived from a heavy- chain only antibody (HCAb) such as from Camelidae origin or Ig-NAR origin such as a variable heavy chain new antigen receptor (VNAR) domain, preferably the HCAb is from Camelidae origin, preferably the sdAb is a VHH domain derived from an HCAb from Camelidae origin (camelid VH) such as derived from an HCAb from camel, lama, alpaca, dromedary, vicuna, guanaco and Bactrian camel. An embodiment is the saponin conjugate according to the invention, wherein the first epitope of the first cell-surface molecule to which the first binding site can bind is a tumor-cell specific first epitope of a first tumor-cell surface molecule, more preferably a tumor-cell specific first epitope of a first tumor-cell surface receptor specifically present on a tumor cell. Thus, preferably, in the saponin conjugate according to the invention, the first epitope of the first cell-surface molecule, to which the proteinaceous molecule 1 can preferably bind, is a tumor-cell specific first epitope of a first tumor-cell surface molecule, more preferably a tumor-cell specific first epitope of a first tumor-cell surface receptor specifically present on a tumor cell. Preferred is the saponin conjugate according to the invention, wherein the proteinaceous molecule 1 comprises a covalently bound effector moiety, and preferably, said effector moiety is an oligonucleotide. Thus, in certain embodiments the saponin conjugate comprises the proteinaceous molecule 1 and an oligonucleotide. Preferred is the saponin conjugate of the invention based on a saponin derivative of the invention and comprising an oligonucleotide, wherein the oligonucleotide comprised by said saponin conjugate is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt. In certain embodiments, the saponin conjugate further comprises a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme), and/or further comprises a non-proteinaceous molecule such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme). In certain embodiments, the saponin conjugate comprises a non-proteinaceous molecule such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme). In certain embodiments, the saponin conjugate comprises a non-proteinaceous cell- surface molecule binding molecule (i.e. a non-proteinaceous ligand for a cell-surface molecule such as a cell-surface receptor) such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris. Preferred is the saponin conjugate of the invention based on a saponin derivative of the invention, wherein the proteinaceous molecule 1 comprised by the saponin conjugate is covalently bound to an oligonucleotide, wherein preferably the oligonucleotide is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt. An aspect of the invention relates to an eighth pharmaceutical composition comprising the saponin conjugate, wherein the proteinaceous molecule 1 comprised by said conjugate comprises a covalently bound effector moiety, and preferably, said effector moiety is an oligonucleotide, and the eighth pharmaceutical composition optionally comprising a pharmaceutically acceptable excipient and/or diluent. According to the invention is the eighth pharmaceutical composition or the saponin conjugate comprised by said eighth pharmaceutical composition, for use as a medicament. According to the invention is the eighth pharmaceutical composition or the saponin conjugate comprised by said eighth pharmaceutical composition, for use in the treatment of a cardiovascular disease or hypercholesterolemia or for use in a method for lowering LDL-cholesterol in the blood of a subject, wherein the effector moiety is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, silencing gene apolipoprotein B (apoB), wherein preferably the oligonucleotide is any one of an AON such as a BNA, a xeno nucleic acid, an siRNA, an antisense oligonucleotide. The inventors established that combining in a single conjugate at least one saponin provided with a semicarbazone functional group according to the invention, a binding partner for a cell receptor (i.e. a ligand) such as an antibody or a binding domain or fragment thereof or such as one or more such as three GalNAc moieties for binding ASGPR, and an effector moiety such as an oligonucleotide e.g. an AON such as a BNA for silencing the HSP27 gene or the apoB gene, provides a conjugate with a higher potency when the activity and effect of the effector moiety in the target cell is considered and compared with the potency and activity achieved with a similar conjugate, though comprising at least one saponin provided with a hydrazone functional group. Without wishing to be bound by any theory, the improved potency is related to more efficacious release of the saponin moiety from the conjugate due to higher susceptibility for bond cleavage under the slightly acidic pH condition in the endosome of the target cell, when the at least one saponin is provided with the semicarbazone functional group. Examples with an antibody- oligonucleotide conjugate (AOC) comprising at least one saponin provided with the semicarbazone functional group covalently bound to the AOC indeed show the improved gene-silencing effect of this conjugate, compared to the similar conjugate though comprising at least one saponin provided with the hydrazone functional group covalently bound to the AOC. Similar improved potency is achieved when the antibody is replaced by at least one GalNAc moiety, preferably three GalNAc moieties, for binding to the cellular asialoglycoprotein receptor (ASGPR). An embodiment is the saponin conjugate according to the invention, wherein the cell- surface molecule targeting (binding) molecule can bind to a tumor-cell surface molecule, preferably a tumor-cell receptor such as a tumor-cell specific receptor, more preferably a receptor selected from CD71, CD63, CA125, EpCAM(17-1A), CD52, CEA, CD44v6, FAP, EGF-IR, integrin, syndecan-1, vascular integrin alpha-V beta-3, HER2, EGFR, CD20, CD22, Folate receptor 1, CD146, CD56, CD19, CD138, CD27L receptor, PSMA, CanAg, integrin-alphaV, CA6, CD33, mesothelin, Cripto, CD3, CD30, CD239, CD70, CD123, CD352, DLL3, CD25, ephrinA4, MUC1, Trop2, CEACAM5, CEACAM6, HER3, CD74, PTK7, Notch3, FGF2, C4.4A, FLT3, CD38, FGFR3, CD7, PD-L1, CTLA4, CD52, PDGFRA, VEGFR1, VEGFR2, preferably selected from CD71, HER2 and EGFR; more preferably wherein the cell-surface molecule targeting (binding) molecule is or comprises a monoclonal antibody or at least one cell-surface molecule binding fragment or -domain thereof, and preferably comprises or consists of any one of cetuximab, daratumumab, gemtuzumab, trastuzumab, panitumumab, brentuximab, inotuzumab, moxetumomab, polatuzumab, obinutuzumab, OKT-9 anti-CD71 monoclonal antibody of the IgG type, pertuzumab, rituximab, ofatumumab, alemtuzumab, pinatuzumab, OKT-10 anti-CD38 monoclonal antibody, an antibody of Table A2, preferably cetuximab or trastuzumab or OKT-9, or at least one cell-surface molecule binding fragment or -domain thereof. An embodiment is the saponin conjugate or the saponin derivative according to the invention, wherein the semicarbazone functional group
Figure imgf000115_0001
is cleavable or hydrolysable under acidic conditions, preferably at pH 4.0 – 6.5, such that the aldehyde group of the saponin on which the saponin derivative is based is formed upon cleavage of the semicarbazone functional group. It is specifically preferred that for the saponin derivative according to the invention and/or the saponin conjugate according to the invention, the semicarbazone functional group
Figure imgf000115_0002
is hydrolysable (cleavable) under acidic conditions, preferably at pH 4.0 – 6.5, wherein hydrolysis of said semicarbazone functional group provides the aldehyde group on the aglycone core structure of the saponin on which the saponin derivative is based. Since the semicarbazone functional group is not hydrolysed at physiological pH as apparent in e.g. the circulation and in tissue of mammals, e.g. human subjects, the saponin in the saponin conjugate is not split off from the conjugate while in the circulation or in tissue. Once the cell-surface molecule binding-molecule of the saponin conjugate, e.g. an antibody, bound to the cell-surface molecule on the target cell, the saponin conjugate is endocytosed by the cell and the saponin conjugate is transferred to and delivered into the cell endosome. In the endosome, the pH is suitable for hydrolysis (cleavage) of the semicarbazone functional group, such that the aldehyde functional group of the saponin on which the saponin conjugate is based, is again formed and the free saponin is provided. The free saponin in the endosome facilitates endosomal escape of any effector molecule or effector moiety into the cytosol, when such effector molecule or effector moiety is co- localized in the endosome. Without wishing to be bound by any theory, conjugating the saponin to a binding molecule through the semicarbazone functional group (e.g., via a maleimide linker) efficiently and sufficiently masks the cytotoxic activity of the free saponin on which the conjugate is based, by altering the initial aldehyde functional group of the saponin into the semicarbazone functional group. Once in the endosome, the semicarbazone functional group is susceptible to hydrolysis at the endosomal acidic pH, stimulating formation of the aldehyde functional group in the saponin, therewith providing the ‘active’ form of the saponin, when endosomal escape enhancing activity is concerned. Once inside the endosome of e.g. an auto-immune cell or a tumor cell, any cytotoxicity of the free saponin comprising the aldehyde functional group is not anymore hampering the benefits of the improved delivery of any effector moiety or molecule in the cytosol. That is to say, in the saponin conjugate, cytotoxicity of the saponin is efficiently blocked, inhibited or diminished, when the conjugate circulates or is present in the body extracellularly, and once inside the endosome, the formed free saponin comprising the aldehyde functional group is an efficient molecule for potentiating a desired effect of an effector molecule or moiety (that is for example co- administered to a subject in the form of for example an ADC, AOC, and capable of binding to the same cell as to which the saponin-conjugate of the invention can bind). An embodiment is the saponin conjugate or the saponin derivative according to the invention, wherein the semicarbazone functional group is cleavable or hydrolysable in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ≤ 5.5, such that the aldehyde group of the saponin on which the saponin derivative is based is formed upon hydrolysis of the semicarbazone functional group. Thus, a specifically preferred embodiment is the saponin derivative according to the invention and/or the saponin conjugate according to the invention, wherein the semicarbazone functional group is subject to hydrolysis in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ≤ 5.5. Surprisingly, the inventors have found that the saponin derivative according to the invention, in particular the saponin derivative according to formula (XII), comprising the semicarbazone functional group hydrolyses more rapidly and in an higher amount towards the corresponding saponin comprising a “free” aldehyde functional group, i.e. native saponin, such as SO1861, as compared to saponin derivatives comprising a hydrazone functional group (=N-N(H)-C(O)-), such as the saponin derivative SO1861-EMCH-blocked according to formula (4) (see formula (4) here below), under acidic conditions, such as at pH 4.0 – 6.5 which are the conditions present in endosomes and/or lysosomes of mammalian cells, such as human cells (see Figures 4A and 4B). This has the benefit that a lower amount of the saponin derivatives according to the invention should be administered to obtain the same amount of saponin comprising the “free” aldehyde to act as endosomal escape enhancers for targeted toxins.
Figure imgf000117_0001
An embodiment is the saponin derivative according to the invention, wherein the saponin derivative is according to molecule (AA):
Figure imgf000117_0002
, wherein
Figure imgf000117_0003
represents a saponin moiety according to formula (SM):
Figure imgf000118_0001
, wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23. The inventors established that the saponin derivative according to molecule (AA) is particularly suitable for synthesizing saponin conjugates of the invention, comprising either at least one GalNAc moiety, preferably three GalNAc moieties, or an oligonucleotide such as a gene- silencing siRNA or BNA, preferably BNA, or both of at least one GalNAc moiety, preferably three GalNAc moieties and an oligonucleotide such as a gene-silencing siRNA or BNA, preferably BNA. Therewith, the inventors now provide the saponin derivative according to molecule (AA) as a semi- product for application in preparing saponin conjugates of the invention, which display enhanced potency with regard to the endosomal escape enhancing activity of the saponin comprised by the conjugate, and which display improved efficacy when the (gene-silencing) effect of an oligonucleotide is considered, when comprised by such a conjugate. Preferred is the saponin derivative according to molecule (BB):
Figure imgf000118_0002
, which molecule (BB) is the covalent conjugation product obtained by the covalent conjugation of the saponin derivative according to molecule (AA) as here above described with the tri-functional linker according to formula (XXI):
Figure imgf000119_0001
(XXI). Such saponin derivative according to molecule (BB) is a semi-product suitable for providing (or synthesis of) a conjugate comprising the saponin with a semicarbazone functional group, and for example comprising a cell-surface receptor ligand such as one to three, preferably 3 GalNAc moieties, and/or an oligonucleotide such as an AON such as an siRNA or a BNA. As said, such as conjugate displays improved potency when the activity of the oligonucleotide is considered, also when the endosomal escape enhancing activity of the saponin is considered. Saponin derivatives of the invention are suitable for conjugation with for example a proteinaceous molecule such as a cell-receptor ligand, an antibody, a binding fragment or domain thereof, such as one or more VHH domains, as outlined here above, as well as for conjugation with for example a non-proteinaceous molecule such as a cell-receptor ligand such as one or more GalNAc moieties, preferably (GalNAc)3Tris. Such a conjugation provides a saponin conjugate of the invention. Preferred is the saponin conjugate of the invention based on a saponin derivative of the invention and comprising an oligonucleotide, wherein the oligonucleotide comprised by said saponin conjugate is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt. In certain embodiments, the saponin conjugate further comprises a proteinaceous molecule such as an antibody or a binding domain or binding fragment thereof, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme), and/or further comprises a non-proteinaceous molecule such as one or more GalNAc moieties, preferably 3 or 4 GalNAc moieties, more preferably 3 GalNAc moieties such as (GalNAc)3Tris, in addition to the oligonucleotide (or, alternatively, in addition to a drug molecule or a (proteinaceous) toxin or an enzyme). An aspect of the invention relates to saponin conjugate according to molecule (CC):
Figure imgf000120_0001
, which molecule (CC) is the covalent conjugation product obtained by the covalent conjugation of the tri-functional linker according to formula (XXI) (as displayed here above) with the saponin derivative according to molecule (AA) as provided here above and with GalNAc conjugate according to molecule (FF):
Figure imgf000120_0002
, wherein
Figure imgf000120_0003
represents the tri-GalNAc conjugate according to molecule (DD1) or according to molecule (DD2):
Figure imgf000121_0001
(DD1), wherein y1, y2 and y3 each are an integer independently selected from 0-20, preferably 1-15, more preferably 2-12, even more preferably 2-10, even more preferably 2-8, most preferably 2 and 3, and preferably y1, y2 and y3 are the same, and y4 is an integer selected from 1-100, preferably 2-80, more preferably 3-70, even more preferably 4-60, even more preferably 4-50, even more preferably 4-40, even more preferably 4-30, even more preferably 4-20, even more preferably 4-6, most preferably 3-5, such as 4;
Figure imgf000122_0001
(DD2), wherein x1, x2 and x3 each are an integer independently selected from 0-20, preferably 1-15, more preferably 2-12, even more preferably 2-10, even more preferably 2-8, most preferably 2 and 3, and preferably x1, x2 and x3 are the same, and x4 is an integer selected from 1-50, preferably 2-40, more preferably 3-30, even more preferably 4-20, even more preferably 5-15, most preferably 8- 12, such as 9, and preferably represents the tri-GalNAc conjugate according to molecule (DD3) or according to molecule (DD4):
Figure imgf000123_0001
(DD4). Such a saponin conjugate according to molecule (CC) is for example a semi-product for preparation of a conjugate further comprising an oligonucleotide such as a gene-silencing BNA or siRNA. In addition, the saponin conjugate according to molecule (CC) is suitable for enhancing the effect and potency of for example a gene-silencing oligonucleotide for example provided with (liver) cell-targeting ligand such as an antibody or one or more GalNAc moieties, preferably three, when cells are contacted with both the saponin conjugate according to molecule (CC) and such an AOC or oligonucleotide-GalNAc conjugate. Such a targeted cell should thus typically expose ASGPR and the binding partner for the antibody (or a binding domain or fragment thereof). An aspect of the invention relates to saponin conjugate according to molecule (EE): e
Figure imgf000124_0002
, which molecule (EE) is the covalent conjugation product obtained by the covalent conjugation of the tri-functional linker according to formula (XXI) (displayed here above) with the saponin derivative according to molecule (AA) as shown here above and with GalNAc conjugate according to molecule (FF) as shown here above and with the oligonucleotide provided with a linker according to molecule (GG):
Figure imgf000124_0001
, wherein the molecule (GG) represents the conjugation product of the conjugation reaction between the linker (E)-1-(4-((2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)hexanoyl)hydrazineylidene)methyl)benzamido)-N-(4-(6-methyl-1,2,4,5-tetrazin-3-yl)benzyl)- 3,6,9,12-tetraoxapentadecan-15-amide and the oligonucleotide-linker molecule according to molecule (HH):
Figure imgf000125_0001
(HH). Such a saponin conjugate according to molecule (EE) of the invention displays a surprisingly improved potency when the endosomal escape enhancing activity of the saponin moiety is considered. It is thought that improved efficacy relates to improved de-coupling (release) of the saponin from the conjugate by cleavage of the semicarbazone functional group under influence of the slightly acidic pH in the endosome of cells which have taken up the conjugate mediated by binding of the conjugate to the ASGPR. Therewith, endosomal escape of the oligonucleotide is enhanced and (gene-silencing) activity of the oligonucleotide in the cytosol and/or in the nucleus is enhanced, compared to applying the similar conjugate though with a hydrazone functional group instead of the semicarbazone functional group of the saponin conjugate according to molecule (EE). An embodiment is the saponin derivative according to the invention wherein the saponin derivative is according to molecule (KK):
Figure imgf000125_0002
, wherein
Figure imgf000125_0003
represents a saponin moiety according to formula (SM):
Figure imgf000126_0001
, wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide according to any one of the oligosaccharides as listed here above, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23 according to any one of the saponins listed here above, and in Table A1. The saponin derivative according to molecule (KK) is for example a derivative suitable for conjugation with e.g. a cell-targeting antibody, e.g. in the context of an ADC or AOC. Molecule (KK) is applicable as a semi-product for synthesizing such an ADC or AOC, providing a single conjugate comprising the cell-targeting moiety (e.g. an antibody or a binding domain thereof), an effector moiety such as a toxin or a (gene-silencing) oligonucleotide (e.g. an AON) such as a BNA or siRNA, and the saponin moiety with improved activity due to enhanced release from the conjugate under influence of slightly acidic pH in the endosome of a targeted cell, by virtue of the presence of the semicarbazone functional group, and as compared with a similar conjugate though comprising the hydrazone functional group instead of the semicarbazone functional group. The saponin derivative according to molecule (KK) is for example also a semi-product for producing a conjugate comprising more than one copies of the saponin moiety comprising the semicarbazone functional group. Examples are the synthesis of a conjugate comprising for example a G2 dendron or G3 dendron and four or eight covalently bound saponin derivatives comprising the semicarbazone functional group. As such, such a dendron-based conjugate with four or eight saponin moieties is a semi- product for providing a conjugate comprising an effector moiety such as a (gene-silencing) oligonucleotide, such as a BNA or an siRNA, and/or comprising a ligand for a cell-surface molecule such as a cell-receptor binding antibody or binding fragment or domain thereof or a cell-surface receptor ligand such as 1-3 GalNAc moieties for binding to ASGPR, preferably three GalNAc moieties. Providing such conjugates of the invention with a single saponin derivative or multiple saponin derivatives provides the opportunity to fine-tune and select the optimal number of saponin moieties most suitable for optimal enhancement of the intracellular potency of the effector molecule such as a gene-silencing oligonucleotide (an AON), e.g. a BNA. That is to say, for certain applications involving a combination of a certain target cell, a certain selected cell-surface molecule such as a receptor, a certain cell-surface molecule binding ligand such as an antibody or 1-3 GalNAc moieties, and a certain effector molecule such as a (gene-silencing) oligonucleotide (e.g. an AON) such as a BNA, presence of a single saponin derivative comprising the semicarbazone functional group in a conjugate of the saponin derivative, the effector molecule and the cell-surface molecule binding ligand may suffice to obtain optimal potency of the effector molecule, whereas for other combinations more than one saponin derivative moieties in the conjugate may be applied to achieve optimal potency, such as 2-32 saponin derivative moieties, preferably 2-16 moieties, more preferably 4-8 moieties, such as 4 or 8 moieties. The saponin derivatives of the invention provide for a flexible platform when adapting the number of saponin derivative moieties in a saponin conjugate of the invention such that optimal efficacy of the effector molecule is achieved, is considered. Indeed, the inventors established that gene silencing was enhanced when the number of saponin derivative moieties comprising the semicarbazone functional group was increased from 1 to 4 to 8 for a conjugate of the invention comprising three GalNAc moieties and a BNA for silencing the apoB gene (see also the Examples section). An aspect of the invention relates to saponin derivative according to molecule (JJ):
Figure imgf000127_0001
which molecule (JJ) is the conjugate product of conjugation of N,N'-((9S,19S)-14-(6- aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo-4,11,14,17- tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide first with the saponin derivative according to molecule (KK), as outlined here above, and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido- 3,6,9,12-tetraoxapentadecan-15-oate. Part of the invention is saponin conjugate according to molecule (LL):
Figure imgf000128_0001
, which molecule (LL) is the covalent conjugation product obtained by the covalent conjugation of the molecule (JJ) as detailed here above with the conjugate of the tri-functional linker and GalNAc according to molecule (MM):
Figure imgf000129_0001
, wherein molecule (MM) is the conjugate of the tri-functional linker according to formula (XXI) as displayed here above and the GalNAc conjugate according to molecule (NN):
Figure imgf000129_0002
, wherein
Figure imgf000129_0003
represents the tri-GalNAc conjugate according to molecule (DD1) or molecule (DD2), preferably molecule (DD3) or molecule (DD4), more preferably molecule (DD3) as detailed here above. An aspect of the invention relates to saponin conjugate according to molecule (PP):
Figure imgf000130_0001
, which molecule (PP) is the covalent conjugation product obtained by the covalent conjugation of the molecule (LL) as given here above with the oligonucleotide provided with a linker according to molecule (GG) as detailed here above. An example of such a saponin conjugate of the invention based on the saponin derivative of the invention, comprising four saponin moieties, is the saponin conjugate displayed in Fig.40F as molecule 42. Synthesis of such a saponin conjugate of the invention comprising four saponin moieties is exemplified by the detailed description of the synthesis of molecule 42 (Fig.40F) in the Examples section here below and displayed in Fig. 40. The saponin moieties are linked to the dendron via a linker, wherein each saponin moiety is linked to a linker via a semicarbazone bond. See also the saponin derivative according to molecule (KK), here above. An embodiment is the saponin conjugate of the invention comprising eight saponin moieties. As said, preferred is the saponin conjugate of the invention, wherein the at least one GalNAc moiety, preferably three GalNAc moieties, the at least one saponin, preferably 1-16 saponin moieties, more preferably 1-8 saponin moieties such as 8 saponin moieties, and the oligonucleotide are covalently bound via a tri-functional linker, preferably with each of the GalNAc moiety or GalNAc moieties, the single saponin or the more than one saponin moieties and the oligonucleotide covalently bound to a separate arm of the tri-functional linker. An embodiment is the saponin conjugate of the invention based on the saponin derivative of the invention, comprising eight saponin moieties covalently bound to a dendron, preferably a G3 dendron. An example of such a (G3) dendron is (2S)-N-[(1S)-1-{[2-(6-amino-N-{2-[(2S)-2,6- bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide. Synthesis of a dendron linked to eight saponin moieties is for example displayed in Fig.41A and in the Examples section for synthesis of Intermediate 25 (molecule 44) from molecule 37 (saponin linked to maleimide involving a semicarbazone bond between the saponin, here SO1861, and the linker bearing the maleimide group), and molecule 43, which is dendron (2S)-N-[(1S)-1-{[2-(6- amino-N-{2-[(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate. An aspect of the invention relates to saponin derivative according to molecule (QQ):
Figure imgf000132_0001
which molecule (QQ) is the conjugate product of conjugation of (2S)-N-[(1S)-1-{[2-(6-amino-N-{2- [(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate first with saponin derivative according to molecule (KK) as detailed here above and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate. An aspect of the invention relates to saponin conjugate according to molecule (RR):
Figure imgf000133_0001
5 (RR) , which molecule (RR) is the covalent conjugation product obtained by the covalent conjugation of the molecule (QQ) as outlined here above with the conjugate of the tri-functional linker and GalNAc according to molecule (MM) as outlined here above. Part of the invention is saponin conjugate according to molecule (SS):
Figure imgf000134_0001
, which molecule (SS) is the covalent conjugation product obtained by the covalent conjugation of the molecule (RR) as detailed here above with the oligonucleotide provided with a linker according to molecule (GG) as detailed here above. An embodiment is the saponin conjugate of the invention, wherein the saponin comprised by the conjugate is any one or more of: a) saponin selected from any one or more of list A: - Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; - Gypsophila elegans saponin mixture, or a saponin isolated from Gypsophila elegans; - Saponinum album saponin mixture, or a saponin isolated from Saponinum album; - Saponaria officinalis saponin mixture, or a saponin isolated from Saponaria officinalis; and - Quillaja bark saponin mixture, or a saponin isolated from Quillaja bark, for example Quil- A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; or b) a saponin comprising a gypsogenin aglycone core structure, selected from list B: SA1641, gypsoside A, NP-017772, NP-017774, NP-017777, NP-017778, NP-018109, NP- 017888, NP-017889, NP-018108, SO1658 and Phytolaccagenin; or c) a saponin comprising a quillaic acid aglycone core structure, selected from list C: AG1856, AG1, AG2, Agrostemmoside E, GE1741, Gypsophila saponin 1 (Gyp1), NP- 017674, NP-017810, NP-003881, NP-017676, NP-017677, NP-017705, NP-017706, NP- 017773, NP-017775, SA1657, Saponarioside B, SO1542, SO1584, SO1674, SO1700, SO1730, SO1772, 10 SO1832, SO1861, SO1862, SO1904, QS-7, QS-7 api, QS-17, QS- 18, QS-21 A-apio, QS-21 A-xylo, QS-21 B-apio and QS-21 B-xylo; preferably, the saponin is any one or more of a saponin selected list B or C, more preferably, a saponin selected from list C. An embodiment is the saponin conjugate of the invention, wherein the saponin is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS- 7, SA1641, a saponin isolated from Saponaria officinalis, Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; preferably wherein the saponin is any one or more of QS-21, SO1832, SO1861, SA1641 and GE1741; more preferably wherein the saponin is QS-21, SO1832 or SO1861; most preferably being SO1861. An embodiment is the saponin conjugate of the invention, wherein the saponin is a saponin isolated from Saponaria officinalis, preferably wherein the saponin is any one or more of Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; more preferably wherein the saponin is any one or more of SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; even more preferably wherein the saponin is any one or more of SO1832, SO1861 and SO1862; even more preferably wherein the saponin is SO1832 and SO1861; most preferably being SO1861. An embodiment is the saponin derivative according to the invention, and for example according to any one of the molecules (AA), (BB), (KK), (JJ) and (QQ) or saponin conjugate according to the invention and according to any one of the molecules (CC), (EE), (LL), (PP), (RR) and (SS), wherein the saponin derivative or the saponin conjugate is based on a saponin according to any one of the saponins listed here above and in Table A1. Preferred is the saponin derivative according to the invention, and for example according to any one of the molecules (AA), (BB), (KK), (JJ) and (QQ) or the saponin conjugate according to the invention and according to any one of the molecules (CC), (EE), (LL), (PP), (RR) and (SS), wherein the saponin derivative or the saponin conjugate is based on a saponin selected from SO1861, SO1832 and QS-21, preferably SO1861 and SO1832, more preferably SO1861. Also preferred is the saponin derivative according to the invention, and for example according to any one of the molecules (AA), (BB), (KK), (JJ) and (QQ) or the saponin conjugate according to the invention and according to any one of the molecules (CC), (EE), (LL), (PP), (RR) and (SS), wherein the semicarbazone functional group is subject to hydrolysis in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ≤ 5.5. An example of such a saponin conjugate of the invention based on the saponin derivative of the invention, comprising eight saponin moieties is the saponin conjugate displayed in Fig.41D as molecule 47. Synthesis of such a saponin conjugate of the invention comprising eight saponin moieties is exemplified by the detailed description of the synthesis of molecule 47 (Fig.41D) in the Examples section here below and displayed in Fig. 41. The saponin moieties are linked to the dendron via a linker, wherein each saponin moiety is linked to a separate linker via a semicarbazone bond. See also the saponin derivative according to molecule (KK), here above. Preferred is the saponin conjugate of the invention based on the saponin derivative of the invention, comprising one saponin moiety, or 4 saponin moieties, preferably 4 saponin moieties covalently bound to a dendron, preferably a G2 dendron such as for example N,N'-((9S,19S)-14- (6-aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo-4,11,14,17- tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide), or 8 saponin moieties, preferably 8 saponin moieties covalently bound to a dendron, preferably a G3 dendron such as for example (2S)-N-[(1S)-1-{[2-(6-amino-N-{2-[(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide. An embodiment is the saponin conjugate according to the invention and for example according to any one of the molecules (EE), (PP) and (SS), wherein the saponin derivative on which the saponin conjugate is based, is a saponin derivative formed upon derivatization of a saponin according to any one of the saponins listed here above and in Table A1. Preferred is the saponin conjugate according to the invention and for example according to any one of the molecules (EE), (PP) and (SS), wherein the saponin conjugate is based on a saponin selected from SO1861, SO1832 and QS-21, preferably SO1861 and SO1832, more preferably SO1861 or SO1832. When the saponin is SO1861, the saponin derivative according to molecule (VII)a:
Figure imgf000137_0001
(VII)a is conjugated with an oligonucleotide and with at least one GalNAc moiety, preferably 3 GalNAc moieties, to provide a saponin conjugate of the invention. An embodiment is the saponin conjugate of the invention, wherein the saponin is SO1861, and wherein the saponin conjugate is provided by conjugation of SO1861 saponin derivative according to molecule (VII)a:
Figure imgf000137_0002
(VII)a with an oligonucleotide and with at least one GalNAc moiety, preferably 3 GalNAc moieties, to provide the saponin conjugate. An embodiment is the saponin conjugate according to the invention and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is any one of an AON, a BNA, a xeno nucleic acid, an siRNA, an antisense oligonucleotide. The saponin conjugate is based on the saponin derivative according to the invention. An embodiment is the saponin conjugate according to the invention and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is selected from any one or more of a(n): short interfering RNA (siRNA), short hairpin RNA (shRNA), anti-hairpin-shaped microRNA (miRNA), single-stranded RNA, aptamer RNA, double-stranded RNA (dsRNA), anti-microRNA (anti-miRNA, anti-miR), antisense oligonucleotide (ASO), DNA, antisense DNA, locked nucleic acid (LNA), bridged nucleic acid (BNA), 2’-O,4’- aminoethylene bridged nucleic acid (BNANC), BNA-based siRNA, and BNA-based antisense oligonucleotide (BNA-AON). Preferred is the saponin conjugate of the invention based on a saponin derivative of the invention and comprising an oligonucleotide, wherein the oligonucleotide comprised by said saponin conjugate is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, preferably being 8 – 100 nt, most preferably being 10 – 50 nt. An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is selected from any one or more of a(n): anti-miRNA, a BNA-AON or an siRNA, such as BNA-based siRNA, selected from chemically modified siRNA, metabolically stable siRNA and chemically modified, metabolically stable siRNA. An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, silencing any one of genes: apolipoprotein B (apoB), HSP27, transthyretin (TTR), proprotein convertase subtilisin/kexin type 9 (PCSK9), TMPRSS6, delta-aminolevulinate synthase 1 (ALAS1), anti-thrombin 3 (AT3), glycolate oxidase (GO), complement component C5 (CC5), X gene of hepatitis B virus (HBV), S gene of HBV, alpha-1 antitrypsin (AAT), miR-122, hepatitis B virus HbsAg, LDHA, CEBPA and lactate dehydrogenase (LDH), and/or is an oligonucleotide capable of, for example when present inside a mammalian cell, targeting an aberrant miRNA. An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, silencing any one of genes: apolipoprotein B (apoB) and HSP27. An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, targeting an mRNA involved in expression of any one of proteins: apoB, HSP27, TTR, PCSK9, TMPRSS6, ALAS1, AT3, GO, CC5, expression product of X gene of HBV, expression product of S gene of HBV, AAT, miR-122, hepatitis B virus HbsAg, LDHA, CEBPA and LDH, or is capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, antagonizing or restoring an miRNA function such as inhibiting an oncogenic miRNA (onco-miR) or suppression of expression of an onco-miR. An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, targeting an mRNA involved in expression of any one of proteins: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AAT, miR-122, hepatitis B virus HbsAg, LDHA and CEBPA. An embodiment is the saponin conjugate according to the invention, based on a saponin derivative of the invention, and for example according to any one of the molecules (EE), (PP) and (SS), comprising an oligonucleotide, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, targeting an mRNA involved in expression of any one of proteins: apoB and HSP27. Pharmaceutical combination and pharmaceutical composition comprising a saponin conjugate An aspect of the invention relates to a second pharmaceutical combination comprising: (a) a fourth pharmaceutical composition comprising the saponin conjugate of the invention and optionally a pharmaceutically acceptable excipient and/or diluent; and (b) a fifth pharmaceutical composition comprising a conjugate comprising a cell-surface molecule binding-molecule, such as a second proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety, wherein the proteinaceous molecule 2 is the same or different from the proteinaceous molecule 1 present in the saponin conjugate, and if the proteinaceous molecule 2 is different from the proteinaceous molecule 1, the proteinaceous molecule 2 comprising a second binding site for binding to a second epitope of a second cell-surface molecule, wherein the second cell-surface molecule is the same as or different from the first cell surface molecule, and if the second cell-surface molecule is different from the first cell surface molecule, the second cell-surface molecule and the first cell surface molecule are preferably present on the same cell, the fifth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent. The effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based. The effector moiety is not the saponin derivative or the saponin conjugate of the invention. Surprisingly, the inventors have found that the saponin derivatives according to the invention which are used as a component for potentiating the intracellular effect of an effector molecule or effector moiety when the effector molecule is provided as a conjugate comprising a cell-surface molecule binding-molecule such as an antibody, e.g. as an ADC or AOC, are now also suitably for (covalent) coupling to a cell-surface molecule binding-molecule such as a cell-surface molecule targeting antibody, such as an sdAb, such that by such coupling the saponin conjugate of the invention is provided, endowed with, for example, anti-tumor activity potentiating activity when used in combination with for example an ADC or an AOC. An embodiment is the fourth pharmaceutical composition according to the invention comprising the saponin conjugate according to the invention, preferably a pharmaceutically acceptable diluent, and further comprising: ^ a pharmaceutically acceptable salt, preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganese, potassium, sodium, strontium, or zinc salt, preferably NaCl; and/or ^ a pharmaceutically acceptable buffer system, such as a phosphate, a borate, a citrate, a carbonate, a histidine, a lactate, a tromethamine, a gluconate, an aspartate, a glutamate, a tartarate, a succinate, a malate, a fumarate, an acetate and/or a ketoglutarate containing buffer system. An embodiment is the fourth pharmaceutical composition according to the invention comprising the saponin conjugate according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and has a pH within the range of 2-11, preferably within the range of 4-9, more preferably within the range of 6-8. An embodiment is the first pharmaceutical composition of the invention, wherein the saponin conjugate is the saponin conjugate according to formula (XII). An embodiment is the second pharmaceutical combination of the invention, comprising: (a) the fourth pharmaceutical composition of the invention comprising the saponin conjugate of the invention, wherein the first epitope on the first cell-surface molecule is a tumor-cell specific first epitope on a first tumor cell-specific surface molecule, preferably a tumor-cell specific first epitope on a first cell-surface receptor specifically present on a tumor cell; and (b) the fifth pharmaceutical composition of the invention, wherein the second cell-surface molecule is a second tumor cell-specific surface molecule which is the same or different from the first tumor cell-specific surface molecule, preferably a second cell-surface receptor specifically present on a tumor cell which is the same or different from the first cell-surface receptor specifically present at said tumor cell, and wherein the second epitope is a tumor-cell specific second epitope, wherein the first epitope and the second epitope, which is the same as or different from the first epitope, are exposed on the same cell. An aspect of the invention relates to a third pharmaceutical combination, comprising: (a) the fourth pharmaceutical composition of the invention comprising the saponin conjugate according to the invention, comprising the first binding site for binding to the first epitope on the first cell-surface molecule, the fourth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent; and (b) a sixth pharmaceutical composition comprising a conjugate comprising a cell-surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, wherein the proteinaceous molecule 3 comprises the first binding site for binding to the first epitope on the cell-surface molecule of (a), the sixth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent, wherein the first binding site of the proteinaceous molecule 1 and the first binding site of the proteinaceous molecule 3 are the same, and wherein the first cell-surface molecule and the first epitope on the first cell-surface molecule, to which the proteinaceous molecule 1 can bind, and the first cell-surface molecule and the first epitope on the first cell-surface molecule, to which the proteinaceous molecule 3 can bind, are the same. The effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based. The effector moiety is not the saponin derivative or the saponin conjugate of the invention. An embodiment is the sixth pharmaceutical composition according to the invention, further comprising: ^ a pharmaceutically acceptable salt, preferably a pharmaceutically acceptable inorganic salt, such as an ammonium, calcium, copper, iron, magnesium, manganese, potassium, sodium, strontium., or zinc salt, preferably NaCl; and/or ^ a pharmaceutically acceptable buffer system, such as a phosphate, a borate, a citrate, a carbonate, a histidine, a lactate, a tromethamine, a gluconate, an aspartate, a glutamate, a tartrate, a succinate, a malate, a fumarate, an acetate and/or a ketoglutarate containing buffer system. An embodiment is the sixth pharmaceutical composition according to the invention comprising the saponin conjugate according to the invention and a pharmaceutically acceptable diluent, preferably water, wherein the composition is liquid at a temperature of 25°C and has a pH within the range of 2-11, preferably within the range of 4-9, more preferably within the range of 6-8. An embodiment is the second pharmaceutical combination or the third pharmaceutical combination according to the invention, wherein the proteinaceous molecule 2 and the proteinaceous molecule 3 is of a type as detailed or the proteinaceous molecule 1, e.g. an antibody or an antigen binding fragment or antigen binding domain thereof, a ligand for a cell-surface molecule or cell-surface receptor such as EGF or a cytokine, an scFv, a Fab, a binding molecule comprising an sdAb, such as a VHH, a binding molecule comprising any of an adnectin, an anticalin, an affibody. The skilled person will appreciate that for the proteinaceous molecule 1 and proteinaceous molecule 2 and proteinaceous molecule 3 any cell-surface molecule binding- molecule can be selected and is suitable for application in the saponin conjugates of the invention and for application in the pharmaceutical compositions and combinations of the invention, that is known today in the technological field of (specifically) targeting a mammalian (aberrant, tumor, auto- immune, etc.) cell with a binding molecule, e.g. for (targeted and specific) delivery of an effector molecule or effector moiety conjugated to the cell-surface molecule binding-molecule. Typical examples of such suitable cell-surface molecule binding-molecules are the antibodies and binding fragments, binding domains and binding derivatives thereof and ligands such as EGF or cytokines used today to deliver drug molecules, payloads, effector moieties, protein toxins, small-molecule toxins, enzymes, oligonucleotides, etc., etc., e.g. in ADCs and AOCs. Any cell-surface molecule binding-molecule applicable for e.g. designing and providing ADCs and AOCs is typically also applicable for providing the saponin conjugate of the invention (e.g., proteinaceous molecule 1). Any cell-surface molecule binding-molecule applicable for e.g. designing and providing ADCs and AOCs is typically also applicable for providing the cell-surface molecule binding-molecule conjugated with an effector moiety, e.g. the proteinaceous molecule 3 and proteinaceous molecule 2 conjugated to an effector moiety. The skilled person will also appreciate that it is within the scope of the invention that for the proteinaceous molecule 1 and proteinaceous molecule 2 and proteinaceous molecule 3 any cell-surface molecule binding-molecule can be selected and is suitable for application in the saponin conjugates of the invention and for application in the pharmaceutical compositions and combinations of the invention, that is known today in the technological field of (specifically) targeting a mammalian (aberrant, tumor, auto-immune, etc.) cell with a binding molecule, e.g. for (targeted and specific) delivery of an effector molecule or effector moiety conjugated to the cell-surface molecule binding-molecule, wherein the cell-surface molecule binding-molecule is either a proteinaceous molecule or a non-proteinaceous molecule. That is to say, according to the invention, any of the cell-surface molecule binding-molecules proteinaceous molecule 1, proteinaceous molecule 2, proteinaceous molecule 3 can be replaced by a non- proteinaceous cell-surface molecule binding-molecule suitable for targeting (binding to) a selected and desired cell such as a mammalian cell, e.g. a tumor cell or an autoreactive immune cell (autoimmune cell). According to the invention, it is preferred that the cell-surface molecules to which combinations of the proteinaceous molecule 1, proteinaceous molecule 2, proteinaceous molecule 3 bind, are present at the surface of the same target cell, when combinations of proteinaceous molecule 1, proteinaceous molecule 2 and proteinaceous molecule 3 bind to different cell-surface molecules. For example, according to the invention, if in pharmaceutical combinations and compositions proteinaceous molecule 1 binds to HER2 and proteinaceous molecule 2 binds to CD71 or EGFR, HER2 and CD71 or HER2 and EGFR are typically present at the same cell. An embodiment is the second pharmaceutical combination or the third pharmaceutical combination according to the invention, wherein the second binding site of the proteinaceous molecule 2 and the first binding site of the proteinaceous molecule 3 is/are or comprise(s) a single- domain antibody (sdAb), preferably VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VHH domain such as derived from a heavy-chain only antibody (HCAb) such as from Camelidae origin or Ig-NAR origin such as a variable heavy chain new antigen receptor (VNAR) domain, preferably the HCAb is from Camelidae origin, preferably the sdAb is a VHH domain derived from an HCAb from Camelidae origin (camelid VH) such as derived from an HCAb from camel, lama, alpaca, dromedary, vicuna, guanaco and Bactrian camel. An embodiment is the second pharmaceutical combination or the third pharmaceutical combination according to the invention, wherein the second epitope of the second cell-surface molecule to which the second binding site can bind is a tumor-cell specific second epitope of a second tumor-cell surface molecule, more preferably a tumor-cell specific second epitope of a second tumor-cell surface receptor specifically present on a tumor cell, and wherein the first epitope of the first cell-surface molecule is a tumor-cell specific first epitope of a first tumor-cell surface molecule, more preferably a tumor-cell specific first epitope of a first tumor-cell surface receptor specifically present on a tumor cell, wherein the second cell-surface molecule and the first cell- surface molecule are present on the same cell. An embodiment is the second pharmaceutical combination or the third pharmaceutical combination according to the invention, wherein the second and third cell-surface molecule binding (targeting) molecule can bind to a tumor-cell surface molecule, preferably a tumor-cell receptor such as a tumor-cell specific receptor, more preferably a receptor selected from CD71, CD63, CA125, EpCAM(17-1A), CD52, CEA, CD44v6, FAP, EGF-IR, integrin, syndecan-1, vascular integrin alpha- V beta-3, HER2, EGFR, CD20, CD22, Folate receptor 1, CD146, CD56, CD19, CD138, CD27L receptor, PSMA, CanAg, integrin-alphaV, CA6, CD33, mesothelin, Cripto, CD3, CD30, CD239, CD70, CD123, CD352, DLL3, CD25, ephrinA4, MUC1, Trop2, CEACAM5, CEACAM6, HER3, CD74, PTK7, Notch3, FGF2, C4.4A, FLT3, CD38, FGFR3, CD7, PD-L1, CTLA4, CD52, PDGFRA, VEGFR1, VEGFR2, preferably selected from CD71, HER2 and EGFR, more preferably wherein the second and third cell-surface molecule binding molecule is or comprises a monoclonal antibody or at least one cell-surface molecule binding fragment or -domain thereof, and preferably comprises or consists of any one of cetuximab, daratumumab, gemtuzumab, trastuzumab, panitumumab, brentuximab, inotuzumab, moxetumomab, polatuzumab, obinutuzumab, OKT-9 anti-CD71 monoclonal antibody of the IgG type, pertuzumab, rituximab, ofatumumab, alemtuzumab, pinatuzumab, OKT-10 anti-CD38 monoclonal antibody, an antibody of Table A2, preferably cetuximab or trastuzumab or OKT-9, or at least one cell-surface molecule binding fragment or - domain thereof. An aspect of the invention relates to a third pharmaceutical combination, comprising: (a) the fourth pharmaceutical composition of the invention and (b) the sixth pharmaceutical composition of the invention, wherein the first cell-surface molecule is expressed on a tumor cell surface, and preferably the first cell-surface molecule is a tumor cell-specific surface molecule, and wherein preferably the first epitope is a first tumor-cell specific epitope. Preferred are the second pharmaceutical combination or third pharmaceutical combination according to the invention, wherein the second binding site of the proteinaceous molecule 2 and/or the first binding site of the proteinaceous molecule 3 comprises or consists of an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, for example camelid VH, or a ligand for a cell-surface molecule such as a receptor such as EGF and a cytokine, preferably VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VHH domain such as derived from a heavy-chain only antibody (HCAb) such as from Camelidae origin or Ig-NAR origin such as a variable heavy chain new antigen receptor (VNAR) domain, preferably the HCAb is from Camelidae origin, preferably the sdAb is a VHH domain derived from an HCAb from Camelidae origin (camelid VH) such as derived from an HCAb from camel, lama, alpaca, dromedary, vicuna, guanaco and Bactrian camel. An aspect of the invention relates to a seventh pharmaceutical composition comprising: (a) the saponin conjugate of the invention; and (b) the conjugate comprising proteinaceous molecule 2 and an effector moiety of the invention, or the conjugate comprising proteinaceous molecule 3 and an effector moiety of the invention, and optionally further comprising a pharmaceutically acceptable excipient and/or diluent. The effector moiety is not a saponin on which the saponin derivative or the saponin conjugate of the invention are based. The effector moiety is not the saponin derivative or the saponin conjugate of the invention. An embodiment is the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, wherein the effector moiety that is comprised by the conjugate comprising a cell-surface molecule binding- molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety or that is comprised by the conjugate comprising a cell-surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, comprises or consists of any one or more of: an oligonucleotide, a nucleic acid and a xeno nucleic acid, preferably selected from any one or more of a vector, a gene, a cell suicide inducing transgene, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), anti-sense oligonucleotide (ASO, AON), short interfering RNA (siRNA), microRNA (miRNA), DNA aptamer, RNA aptamer, mRNA, mini-circle DNA, peptide nucleic acid (PNA), phosphoramidate morpholino oligomer (PMO), locked nucleic acid (LNA), bridged nucleic acid (BNA), 2’-deoxy-2’-fluoroarabino nucleic acid (FANA), 2’-O- methoxyethyl-RNA (MOE), 2'-O,4'-aminoethylene bridged nucleic acid, 3’-fluoro hexitol nucleic acid (FHNA), a plasmid, glycol nucleic acid (GNA) and threose nucleic acid (TNA), or a derivative thereof, more preferably a BNA, for example a BNA for silencing HSP27 or apoB protein expression. An embodiment is the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, wherein the effector moiety that is comprised by the conjugate comprising a cell-surface molecule binding- molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety or that is comprised by the conjugate comprising a cell-surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, comprises or consists of any one or more of: at least one proteinaceous molecule, preferably selected from any one or more of a peptide, a protein, protein toxin, an enzyme such as urease and Cre-recombinase, a ribosome-inactivating protein, and more preferably selected from any one or more of a viral toxin such as apoptin; a bacterial toxin such as Shiga toxin, Shiga-like toxin, Pseudomonas aeruginosa exotoxin (PE) or exotoxin A of PE, full-length or truncated diphtheria toxin (DT), cholera toxin; a fungal toxin such as alpha-sarcin; a plant toxin including ribosome- inactivating proteins and the A chain of type 2 ribosome-inactivating proteins such as dianthin e.g. dianthin-30 or dianthin-32, saporin e.g. saporin-S3 or saporin-S6, bouganin or de-immunized derivative debouganin of bouganin, shiga-like toxin A, pokeweed antiviral protein, ricin, ricin A chain, modeccin, modeccin A chain, abrin, abrin A chain, volkensin, volkensin A chain, viscumin, viscumin A chain; or an animal or human toxin such as frog RNase, or granzyme B or angiogenin from humans, or any fragment or derivative thereof; preferably the protein toxin is dianthin and/or saporin. An embodiment is the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, wherein the effector moiety that is comprised by the conjugate comprising a cell-surface molecule binding- molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety or that is comprised by the conjugate comprising a cell-surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, comprises or consists of any one or more of: at least one payload, preferably selected from any one or more of a toxin targeting ribosomes, a toxin targeting elongation factors, a toxin targeting tubulin, a toxin targeting DNA and a toxin targeting RNA, more preferably any one or more of emtansine, pasudotox, maytansinoid derivative DM1, maytansinoid derivative DM4, monomethyl auristatin E (MMAE, vedotin), monomethyl auristatin F (MMAF, mafodotin), a calicheamicin, N-Acetyl- γ-calicheamicin, a pyrrolobenzodiazepine (PBD) dimer, a benzodiazepine, a CC-1065 analogue, a duocarmycin, doxorubicin, paclitaxel, docetaxel, cisplatin, cyclophosphamide, etoposide, docetaxel, 5-fluorouracyl (5-FU), mitoxantrone, a tubulysin, an indolinobenzodiazepine, AZ13599185, a cryptophycin, rhizoxin, methotrexate, an anthracycline, a camptothecin analogue, SN-38, DX-8951f, exatecan mesylate, truncated form of Pseudomonas aeruginosa exotoxin (PE38), a duocarmycin derivative, an amanitin, α-amanitin, a spliceostatin, a thailanstatin, ozogamicin, tesirine, Amberstatin269 and soravtansine, or a derivative thereof. An aspect of the invention relates to the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, for use as a medicament. An aspect of the invention relates to the second pharmaceutical combination or third pharmaceutical combination of the invention, or the seventh pharmaceutical composition of the invention, for use in the treatment or prevention of a cancer or of an autoimmune disease such as rheumatoid arthritis. An aspect of the invention relates to a ninth pharmaceutical composition comprising the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), and optionally a pharmaceutically acceptable excipient and/or optionally a pharmaceutically acceptable diluent. An aspect of the invention relates to the ninth pharmaceutical composition of the invention or to the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use as a medicament. An aspect of the invention relates to the ninth pharmaceutical composition of the invention or to the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use in the treatment or prophylaxis of a disease or health problem in which an expression product is involved of any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AT3, GO, CC5, X gene of HBV, S gene of HBV, AAT, miR-122, hepatitis B virus HbsAg, LDHA, CEBPA and LDH, and/or for use in the treatment or prophylaxis of a disease or health problem which involves any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AT3, GO, CC5, X gene of HBV, S gene of HBV, AAT, miR-122, hepatitis B virus HbsAg, LDHA, CEBPA and LDH. An aspect of the invention relates to the ninth pharmaceutical composition of the invention or to the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use in the treatment or prophylaxis of a disease or health problem in which an expression product is involved of any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AAT, miR-122, hepatitis B virus HbsAg, LDHA and CEBPA, and/or for use in the treatment or prophylaxis of a disease or health problem which involves any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AAT, miR-122, hepatitis B virus HbsAg, LDHA and CEBPA. An embodiment is the ninth pharmaceutical composition of the invention or the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use as here above outlined, wherein said use is in the treatment or prophylaxis of a disease or health problem in which an expression product is involved of any one or more of genes: HSP27 and apoB, preferably apoB, and/or for use in the treatment or prophylaxis of a disease or health problem which involves any one or more of genes: HSP27 and apoB, preferably apoB. An embodiment is the ninth pharmaceutical composition of the invention or the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use as here above outlined, for use in the treatment or prophylaxis of a cancer, an infectious disease, a viral infection, hypercholesterolemia, cardiovascular disease, primary hyperoxaluria, haemophilia A, haemophilia B, AAT related liver disease, acute hepatic porphyria, TTR-mediated amyloidosis, hereditary TTR amyloidosis (hATTR), complement-mediated disease, hepatitis B infection, hepatitis C infection, α1-antitrypsin deficiency, β-thalassaemia, or an auto- immune disease. An embodiment is the ninth pharmaceutical composition of the invention or the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use as here above outlined, wherein said use is in the treatment or prophylaxis of a cancer such as endometrial carcinoma, breast cancer, lung cancer or hepatocellular carcinoma, and/or a cardiovascular disease such as hypercholesterolemia, preferably hypercholesterolemia. An aspect of the invention relates to the ninth pharmaceutical composition of the invention or to the saponin conjugate of the invention and (for example) according to any one of the molecules (EE), (PP) and (SS), for use in the lowering of LDL-cholesterol in a subject.
Figure imgf000147_0001
Figure imgf000148_0001
Figure imgf000149_0001
Figure imgf000150_0001
Figure imgf000151_0001
Figure imgf000152_0001
It is preferred that the saponin of the saponin derivative and the saponin conjugate based on the saponin derivative is a saponin derived from a plant. The saponin on which the saponin derivative is based and the saponin comprised by the saponin conjugate of the invention is preferably a saponin isolated from a plant. The term ‘plant’ is to be understood to include plants and trees. For example, the saponin is isolated from the root of a plant or from the bark of a tree. Examples of such plants from which the saponin is derived (isolated) are Quillaja saponaria, Gypsophila paniculate L., Saponaria officinalis such as Saponaria officinalis L. and Gypsophila elegans such as Gypsophila elegans M. Bieb. Preferably, the saponin derivative and the saponin conjugate comprise a single type of saponin, preferably a single type of saponin derived from plant material such as the roots of a plant, such as SO1861, SO1862 or SO1832 from Saponaria officinalis (e.g., Saponaria officinalis L.) (roots) or such as a QS-21, a QS-7 or a QS-17 from Quillaja saponaria (roots). Suitable sources for isolating saponins according to the invention, i.e. those that display endosomal escape enhancing activity (see Table A1 for examples), are Quillaja saponaria, Gypsophila paniculate L., Saponaria officinalis and Gypsophila elegans, and Quillaja bark. Saponin suitable for the saponin derivative of the invention and for the saponin conjugate of the invention are thus for example: Quillaja saponaria saponin, saponin isolated from Quillaja saponaria, for example Quil-A, QS-17- api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl, Saponinum album, saponin isolated from Saponinum album, Saponaria officinalis saponin, saponin isolated from Saponaria officinalis (preferred), Quillaja bark saponin, saponin isolated from Quillaja bark saponin, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl. In addition, apart from QS-21, also the individual saponins present in QS-21 are suitable saponins for the saponin derivative and the saponin conjugate of the invention, i.e. the saponins depicted as the saponins of SCHEME Q:
Figure imgf000154_0001
An embodiment is the saponin derivative of the invention, or the saponin conjugate of the invention, wherein the saponin on which the saponin derivative is based or on which the saponin conjugate is based, is isolated from a plant. Preferably, the saponin is isolated from a part of a plant, such as the root, or from a part of a tree, such as the bark. Preferably, the saponin is isolated from roots derived from a plant.
Figure imgf000155_0001
The invention is further illustrated by the following examples, which should not be interpreted as limiting the present invention in any way. EXAMPLES Example 1 EXAMPLES Materials and Methods Abbreviations Ab Antibody AEM N-(2-Aminoethyl)maleimide trifluoroacetate salt AMPD 2-Amino-2-methyl-1,3-propanediol BOC tert-Butyloxycarbonyl BOP (Benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate DCM dichloromethane DIPEA N,N-diisopropylethylamine DMF N,N-dimethylformamide DMSO Dimethylsulfoxid DTME dithiobismaleimidoethane DTT dithiothreitol EDCI.HCl 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride EDTA ethylenediaminetetraacetic acid EMCH.TFA N-(ε-maleimidocaproic acid) hydrazide, trifluoroacetic acid salt HATU 1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3- oxid hexafluorophosphate mab monoclonal antibody min minutes NEM N-Ethylmaleimide NMM 4-methylmorpholine r.t. retention time SC semicarbazone SEC size exclusion chromatography TBEU (Tris-(hydroxymethyl)-aminomethan)-Borat-EDTA-Urea TCEP tris(2-carboxyethyl)phosphine hydrochloride Temp temperature TFA trifluoroacetic acid THF tetrahydrofuran Materials Trastuzumab (Herceptin®, Roche), cetuximab (Erbitux®, Merck KGaA) were purchased from the pharmacy (Charité, Berlin). CD71 monoclonal antibody was purchased from BioXCell (OKT9, #BE0023). SO1861 was isolated and purified by Analyticon Discovery GmbH from raw plant extract obtained from Saponaria officinalis L. EGF-dianthin was produced from E.coli according to standard procedures. HSP27BNA oligo and ApoB and ApoB#02 were produced by Bio-Synthesis Inc, (Lewisville). Tris(2-carboxyethyl)phosphine hydrochloride (TCEP, 98%, Sigma-Aldrich), 5,5- Dithiobis(2-nitrobenzoic acid) (DTNB, Ellman’s reagent, 99%, Sigma-Aldrich), Zeba™ Spin Desalting Columns (2 mL, Thermo-Fisher), NuPAGE™ 4-12% Bis-Tris Protein Gels (Thermo- Fisher), NuPAGE™ MES SDS Running Buffer (Thermo-Fisher), Novex™ Sharp Pre-stained Protein Standard (Thermo-Fisher), PageBlue™ Protein Staining Solution (Thermo-Fischer), Pierce™ BCA Protein Assay Kit (Thermo-Fisher), N-Ethylmaleimide (NEM, 98%, Sigma-Aldrich), 1,4-Dithiothreitol (DTT, 98%, Sigma-Aldrich), Sephadex G25 (GE Healthcare), Sephadex G50 M (GE Healthcare), Superdex 200P (GE Healthcare), Isopropyl alcohol (IPA, 99.6%, VWR), Tris(hydroxymethyl)aminomethane (Tris, 99%, Sigma-Aldrich), Tris(hydroxymethyl)aminomethane hydrochloride (Tris.HCL, Sigma-Aldrich), L-Histidine (99%, Sigma-Aldrich), D-(+)-Trehalose dehydrate (99%, Sigma-Aldrich), Polyethylene glycol sorbitan monolaurate (TWEEN 20, Sigma- Aldrich), Dulbecco's Phosphate-Buffered Saline (DPBS, Thermo-Fisher), Guanidine hydrochloride (99%, Sigma-Aldrich), Ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA-Na2, 99%, Sigma-Aldrich), sterile filters 0.2 µm and 0.45 µm (Sartorius), Succinimidyl 4-(N- maleimidomethyl)cyclohexane-1-carboxylate (SMCC, Thermo-Fisher), Vivaspin T4 and T15 concentrator (Sartorius), Superdex 200PG (GE Healthcare), Tetra(ethylene glycol) succinimidyl 3- (2-pyridyldithio)propionate (PEG4-SPDP, Thermo-Fisher), [O-(7-Azabenzotriazol-1-yl)-N,N,N,N- tetramethyluronium-hexafluorphosphat] (HATU, 97%, Sigma-Aldrich), Dimethyl sulfoxide (DMSO, 99%, Sigma-Aldrich), N-(2-Aminoethyl)maleimide trifluoroacetate salt (AEM, 98 %, Sigma-Aldrich), L-Cysteine (98.5%, Sigma-Aldrich), deionized water (DI) was freshly taken from Ultrapure Lab Water Systems (MilliQ, Merck), Nickel-nitrilotriacetic acid agarose (Ni-NTA agarose, Protino), Glycine (99.5 %, VWR), 5,5-Dithiobis(2-nitrobenzoic acid (Ellman’s reagent, DTNB, 98%, Sigma- Aldrich), S-Acetylmercaptosuccinic anhydride Fluorescein (SAMSA reagent, Invitrogen), Sodium bicarbonate (99.7%, Sigma-Aldrich), Sodium carbonate (99.9%, Sigma-Aldrich), PD MiniTrap desalting columns with Sephadex G-25 resin (GE Healthcare), PD10 G25 desalting column (GE Healthcare), Zeba Spin Desalting Columns in 0.5, 2, 5, and 10 mL (Thermo-Fisher), Vivaspin Centrifugal Filters T410 kDa MWCO, T4100 kDa MWCO, and T15 (Sartorius), Biosep s3000 aSEC column (Phenomenex), Vivacell Ultrafiltration Units 10 and 30 kDa MWCO (Sartorius), Nalgene Rapid-Flow filter (Thermo-Fisher), dichlormethan (Sigma-Aldrich), methanol (Sigma-Aldrich), diethyl ether (Sigma-Aldrich), acetonitrile (Sigma-Aldrich), Pyridine 2-thione (Sigma-Aldrich), Goat anti-Human IgG – HRP (Southern Biotech), Goat anti-Human Kappa – HRP (Southern Biotech), Tris concentrate (Thermo-Fisher), MOPS running buffer (20x, Thermo-Fisher), LDS sample buffer (4x, Thermo-Fisher), TBS Blocking Buffer (Thermo-Fisher), Tris (Tris(hydroxymethyl)aminomethane, Merck), Tris HCl (Sigma-Aldrich), Minisart RC150.2 μm filter (Sartorius), Minisart 0.45 μm filter (Sartorius), PD Minitrap G25 (Cytiva), TNBS (2,4,6- trinitrobenzene sulfonic acid, Sigma-Aldrich), Sodium Dodecyl Sulfate (SDS, Sigma-Aldrich), SMCC (succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, Thermo-Fisher), THPP (Tris(hydroxypropyl)phosphine, Sigma-Aldrich), DBCO-NHS (CAS 1353016-71-3, BroadPharm), PEG4-SPDP (2-Pyridyldithiol-tetraoxatetradecane-N-hydroxysuccinimide, Thermo-Fisher), Novex™ TBE-Urea Gels, 15% (Thermo-Fisher), TBE buffer (Tris-Borat-EDTA, Thermo-Fisher). Methods Analytical methods LC-MS method 1, 1 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, pos/neg 100-800; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Acquity C18, 50×2.1 mm, 1.7 μm Temp: 60ºC, Flow: 0.6 mL/min, Gradient: t0 = 5% B, t2.0min = 98% B, t2.7min = 98% B, Post time: 0.3 min, Eluent A: 0.1% formic acid in water, Eluent B: 0.1% formic acid in acetonitrile. LC-MS method 1 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, mass ranges depending on the molecular weight of the product: neg or neg/pos within in a range of 1500-2400 or 2000-3000; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Acquity C18, 50×2.1 mm, 1.7 μm Temp: 60ºC, Flow: 0.6 mL/min, lin. Gradient depending on the polarity of the product: At0 = 2% A, t5.0min = 50% A, t6.0min = 98% A Bt0 = 2% A, t5.0min = 98% A, t6.0min = 98% A Posttime: 1.0 min, Eluent A: acetonitrile, Eluent B: 10 mM ammonium bicarbonate in water (pH=9.5). LC-MS method 1, 1,2 Apparatus: Agilent 1200 Bin. Pump: G1312A, degasser; autosampler, ColCom, DAD: Agilent G1316A, 210, 220 and 220-320 nm, PDA: 210-320 nm, MSD: Agilent LC/MSD G6130B ESI, pos/neg 100-1000; ELSD Alltech 3300 gas flow 1.5 ml/min, gas temp: 40°C; column: Waters XSelectTM CSH C18, 30×2.1 mm, 3.5 μm, Temp: 35ºC, Flow: 1 mL/min, Gradient: t0 = 5% A, t1.6min = 98% A, t3min = 98% A, Posttime: 1.3 min, Eluent A: 0.1% formic acid in acetonitrile, Eluent B: 0.1% formic acid in water. LC-MS method 1, 2 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, neg 2000-3000; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Acquity C18, 50×2.1 mm, 1.7 μm Temp: 60ºC, Flow: 0.6 mL/min, Gradient: t0 = 5% B, t5.0min = 98% B, t6.0min = 98% B, Post time: 1.0 min, Eluent A: 0.1% formic acid in water, Eluent B: 0.1% formic acid in acetonitrile. LC-MS method 2 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, mass ranges depending on the molecular weight of the product: pos/neg 100-800 or neg 2000-3000; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Waters XSelectTM CSH C18, 50×2.1 mm, 2.5 μm, Temp: 25°C, Flow: 0.5 mL/min, Gradient: t0min = 5% A, t2.0min = 98% A, t2.7min = 98% A, Posttime: 0.3 min, Eluent A: acetonitrile, Eluent B: 10 mM ammonium bicarbonate in water (pH = 9.5). LC-MS method 2, 2 Apparatus: Agilent 1260 Bin. Pump: G7112B, Multisampler, Column Comp, DAD: Agilent G7115A, 210, 220 and 220-320 nm, PDA: 210-320 nm, MSD: Agilent LC/MSD G6130B ESI, mass ranges depending on the molecular weight of the product: Apos/neg 100-1000 Bpos/neg 100-1400 ; ELSD Alltech 3300 gas flow 1.5 ml/min, gas temp: 40°C; column: Waters XSelectTM C18, 30×2.1 mm, 3.5 μm, Temp: 40ºC, Flow: 1 mL/min, Gradient: t0 = 5% A, t1.6min = 98% A, t3min = 98% A, Posttime: 1.3 min, Eluent A: 0.1% formic acid in acetonitrile, Eluent B: 0.1% formic acid in water. LC-MS method 1, 3 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, neg/pos 1500-2400; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Acquity C18, 50×2.1 mm, 1.7 μm Temp: 60ºC, Flow: 0.6 mL/min, lin. Gradient depending on the polarity of the product: t0 = 2% B, t5.0min = 98% B, t6.0min = 98% B, Post time: 1.0 min, Eluent A: 10 mM ammonium bicarbonate in water (pH = 9.5), Eluent B: acetonitrile. LC-MS method 3 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, mass ranges depending on the molecular weight of the product pos/neg 105-800, 500-1200 or 1500-2500; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Waters XSelectTM CSH C18, 50×2.1 mm, 2.5 μm, Temp: 40°C, Flow: 0.5 mL/min, Gradient: t0min = 5% A, t2.0min = 98% A, t2.7min = 98% A, Posttime: 0.3 min, Eluent A: 0.1% formic acid in acetonitrile, Eluent B: 0.1% formic acid in water. LC-MS method 3, 3 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, pos/neg 800-1500; ELSD: gaspressure 40 psi, drift tube temp: 50°C; column: Waters XSelectTM CSH C18, 50×2.1 mm, 2.5 μm Temp: 25ºC, Flow: 0.6 mL/min, Gradient: t0 = 5% A, t2.0min = 98% A, t2.7min = 98% A, Posttime: 0.3 min, Eluent A: acetonitrile, Eluent B: 10 mM ammonium bicarbonate in water (pH = 9.5). LC-MS method 1, 4 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, neg/pos 1500-2400; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Acquity C18, 50×2.1 mm, 1.7 μm Temp: 60ºC, Flow: 0.6 mL/min, lin. Gradient depending on the polarity of the product: t0 = 2% B, t5.0min = 50% B, t6.0min = 98% B, Post time: 1.0 min, Eluent A: 10 mM ammonium bicarbonate in water (pH = 9.5), Eluent B: acetonitrile. LC-MS method 4 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, mass ranges depending on the molecular weight of the product: pos/neg 100-800 or neg 2000-3000; ELSD: gas pressure 40 psi, drift tube temp: 50°C column: Waters Acquity Shield RP18, 50×2.1 mm, 1.7 μm, Temp: 25ºC, Flow: 0.5 mL/min, Gradient: t0min = 5% A, t2.0min = 98% A, t2.7min = 98% A, Posttime: 0.3 min, Eluent A: acetonitrile, Eluent B: 10 mM ammonium bicarbonate in water (pH=9.5). LC-MS method 4, 4 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, pos/neg 1500-2500; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Waters XSelectTM CSH C18, 50×2.1 mm, 2.5 μm Temp: 25ºC, Flow: 0.6 mL/min, Gradient: t0 = 15% A, t2.0min = 60% A, t2.7min = 98% A, Posttime: 0.3 min, Eluent A: acetonitrile, Eluent B: 10 mM ammonium bicarbonate in water (pH = 9.5). LC-MS method 5, 5 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, mass ranges depending on the molecular weight of the product: Apos/neg 1500-2500 Bneg 2000-3000 ; ELSD: gaspressure 40 psi, drift tube temp: 50°C; column: Acquity C18, 50×2.1 mm, 1.7 μm Temp: 60ºC, Flow: 0.6 mL/min, Gradient: t0 = 2% A, t5.0min = 50% A, t6.0min = 98% A, Posttime: 1.0 min, Eluent A: acetonitrile, Eluent B: 10 mM ammonium bicarbonate in water (pH=9.5). Preparative methods Preparative MP-LC method 1, 1 Instrument type: Reveleris™ prep MPLC; Column: Phenomenex LUNA C18(3) (150×25 mm, 10 μm); Flow: 40 mL/min; Column temp: room temperature; Eluent A: 0.1% (v/v) Formic acid in water, Eluent B: 0.1% (v/v) Formic acid in acetonitrile; Gradient: t0min = 5% B, t1min = 5% B, t2min = 20% B, t17min = 60% B, t18min = 100% B, t23min = 100% B; Detection UV : 210, 235, 254 nm and ELSD. Preparative MP-LC method 2, 2 Instrument type: Reveleris™ prep MPLC; column: Waters XSelectTM CSH C18 (145×25 mm, 10 μm); Flow: 40 mL/min; Column temp: room temperature; Eluent A: 10 mM ammonium bicarbonate in water pH = 9.0); Eluent B: 99% acetonitrile + 1% 10 mM ammonium bicarbonate in water; Gradient: t0min = 5% B, t1min = 5% B, t2min = 10% B, t17min = 50% B, t18min = 100% B, t23min = 100% B; Detection UV: 210, 235, 254 nm and ELSD. Preparative MP-LC method 1 Instrument type: Reveleris™ prep MPLC; column: Waters XSelectTM CSH C18 (145×25 mm, 10 μm); Flow: 40 mL/min; Column temp: room temperature; Eluent A: 10 mM ammonium bicarbonate in water pH = 9.0); Eluent B: 99% acetonitrile + 1% 10 mM ammonium bicarbonate in water; Gradient: At0min = 5% B, t1min = 5% B, t2min = 10% B, t17min = 50% B, t18min = 100% B, t23min = 100% B At0min = 5% B, t1min = 5% B, t2min = 20% B, t17min = 60% B, t18min = 100% B, t23min = 100% B ; Detection UV: 210, 235, 254 nm and ELSD. Preparative MP-LC method 2 Instrument type: Reveleris™ prep MPLC; Column: Phenomenex LUNA C18(3) (150×25 mm, 10 μm); Flow: 40 mL/min; Column temp: room temperature; Eluent A: 0.1% (v/v) Formic acid in water, Eluent B: 0.1% (v/v) Formic acid in acetonitrile; Gradient: At0min = 5% B, t1min = 5% B, t2min = 20% B, t17min = 60% B, t18min = 100% B, t23min = 100% B Bt0min = 2% B, t1min = 2% B, t2min = 2% B, t17min = 30% B, t18min = 100% B, t23min = 100% B Ct0min = 5% B, t1min = 5% B, t2min = 10% B, t17min = 50% B, t18min = 100% B, t23min = 100% B Dt0min = 5% B, t1min = 5% B, t2min = 5% B, t17min = 40% B, t18min = 100% B, t23min = 100% B ; Detection UV : 210, 235, 254 nm and ELSD. Preparative LC-MS method 3 MS instrument type: Agilent Technologies G6130B Quadrupole; HPLC instrument type: Agilent Technologies 1290 preparative LC; Column: Waters XSelectTM CSH (C18, 150×19 mm, 10 µm); Flow: 25 ml/min; Column temp: room temperature; Eluent A: 100% acetonitrile; Eluent B: 10 mM ammonium bicarbonate in water pH = 9.0; Gradient: At0 = 20% A, t2.5min = 20% A, t11min = 60% A, t13min = 100% A, t17min = 100% A Bt0 = 5% A, t2.5min = 5% A, t11min = 40% A, t13min = 100% A, t17min = 100% A ; Detection: DAD (210 nm); Detection: MSD (ESI pos/neg) mass range: 100 – 800; Fraction collection based on DAD. Preparative LC-MS method 4 MS instrument type: Agilent Technologies G6130B Quadrupole; HPLC instrument type: Agilent Technologies 1290 preparative LC; Column: Waters XBridge Protein (C4, 150×19 mm, 10 µm); Flow: 25 ml/min; Column temp: room temperature; Eluent A: 100% acetonitrile; Eluent B: 10 mM ammonium bicarbonate in water pH = 9.0; Gradient: At0 = 2% A, t2.5min = 2% A, t11min = 30% A, t13min = 100% A, t17min = 100% A Bt0 = 10% A, t2.5min = 10% A, t11min = 50% A, t13min = 100% A, t17min = 100% A Ct0 = 5% A, t2.5min = 5% A, t11min = 40% A, t13min = 100% A, t17min = 100% A ; Detection: DAD (210 nm); Detection: MSD (ESI pos/neg) mass range: 100 – 800; Fraction collection based on DAD Preparative MP-LC method 1, 1 Instrument type: Reveleris™ prep MPLC; column: Waters XSelectTM CSH C18 (145×25 mm, 10 μm); Flow: 40 mL/min; Column temp: room temperature; Eluent A: 10 mM ammonium bicarbonate in water pH = 9.0); Eluent B: 99% acetonitrile + 1% 10 mM ammonium bicarbonate in water; Gradient: t0min = 5% B, t1min = 5% B, t2min = 10% B, t17min = 50% B, t18min = 100% B, t23min = 100% B; Detection UV: 210, 225, 285 nm. Preparative MP-LC method 2, 2 Instrument type: Reveleris™ prep MPLC; Column: Phenomenex LUNA C18(3) (150×25 mm, 10 μm); Flow: 40 mL/min; Column temp: room temperature; Eluent A: 0.1% (v/v) Formic acid in water, Eluent B: 0.1% (v/v) Formic acid in acetonitrile; Gradient: t0min = 5% B, t1min = 5% B, t2min = 10% B, t17min = 50% B, t18min = 100% B, t23min = 100% B; Detection UV : 210, 225, 285 nm. Preparative LC-MS method 1, 3 MS instrument type: Agilent Technologies G6130B Quadrupole; HPLC instrument type: Agilent Technologies 1290 preparative LC; Column: Waters XSelectTM CSH (C18, 100×30 mm, 10 µm); Flow: 25 ml/min; Column temp: room temperature; Eluent A: 100% acetonitrile; Eluent B: 10 mM ammonium bicarbonate in water pH=9.0; lin. gradient depending on the polarity of the product: At0 = 20% A, t2min = 20% A, t8.5min = 60% A, t10min = 100% A, t13min = 100% A Bt0 = 5% A, t2min = 5% A, t8.5min = 40% A, t10min = 100% A, t13min = 100% A Ct0 = 10% A, t2min = 10% A, t8.5min = 50% A, t10min = 100% A, t13min = 100% A ; Detection: DAD (220-320 nm); Detection: MSD (ESI pos/neg) mass range: 100 – 800; Fraction collection based on DAD. Preparative LC-MS method 2, 4 MS instrument type: Agilent Technologies G6130B Quadrupole; HPLC instrument type: Agilent Technologies 1290 preparative LC; column: Waters XBridge Shield (C18, 150×19mm, 5 µm); Flow: 25 ml/min; Column temp: room temperature; Eluent A: 100% acetonitrile; Eluent B: 10 mM ammonium bicarbonate in water pH=9.0; lin. gradient: t0 = 5% A, t2.5min = 5% A, t11min = 40% A, t13min = 100% A, t17min = 100% A; Detection: DAD (220-320 nm); Detection: MSD (ESI pos/neg) mass range: 100 – 800; Fraction collection based DAD. Flash chromatography Grace Reveleris X2® C-815 Flash; Solvent delivery system: 3-piston pump with auto-priming, 4 independent channels with up to 4 solvents in a single run, auto-switches lines when solvent depletes; maximum pump flow rate 250 mL/min; maximum pressure 50bar (725psi); Detection: UV 200-400 nm, combination of up to 4 UV signals and scan of entire UV range, ELSD; Column sizes: 4-330g on instrument, luer type, 750g up to 3000g with optional holder. Further methods UV-vis spectrophotometry Protein concentrations were determined using a Thermo Nanodrop 2000 spectrometer and the following extinction coefficient ε280 values ((mg/ml)-1 cm-1); Oligo concentrations were determined using a molar extinction coefficient ε260 value of 153,000 M-1 cm-1. Ellman’s assay was carried out using a Perkin Elmer Lambda 25 Spectrophotometer and a literature derived molar extinction coefficient ε412 value of 14150 M-1 cm-1 for TNB. Experimentally determined molar extinction coefficients ε495 = 58,700 M-1 cm-1 and Rz280:495 = 0.428 were used for SAMSA-fluorescein. TNBS assay Glycine standards (0, 2.5, 5, 10, 15 and 20 μg/ml) were freshly prepared using DPBS pH 7.5. TNBS assay reagent was prepared by combining TNBS (40 μl) and DPBS pH 7.5 (9.96 ml).10% w/v SDS was prepared using DI water. For the assay, 60 μl of each sample (singlicate) and standard (triplicate) were plated out. To each well was added TNBS reagent (60 μl) and incubated on a plate shaker for 3 hours at 37°C and 600rpm. Afterwards, 50 μl of 10% SDS and 25 μl 1M HCl were added and the plate optical density was analysed at 340 nm. Lysine-targeting molecule incorporation determined by depletion of lysine concentration of conjugate with respect to unmodified protein. SEC The conjugates were analysed by SEC using an Akta Purifier 10 system and Biosep SEC-s3000 column eluting with DPBS:IPA (85:15). Conjugate purity was determined by integration of the conjugate UV absorbance peak versus integrated impurities/aggregate forms UV absorbance peaks. SDS-PAGE and Western Blotting Native proteins and conjugates were analysed under heat denaturing non-reducing and reducing conditions by SDS-PAGE against a protein ladder using a 4-12% bis-tris gel and MES as running buffer (200V, ~40 minutes). Samples were prepared to 0.5 mg/ml, comprising LDS sample buffer and MOPS running buffer as diluent. For reducing samples, DTT was added to a final concentration of 50 mM. Samples were heat treated for 2 minutes at 90-95°C and 5 μg (10 μl) added to each well. Protein ladder (10 μl) was loaded without pre-treatment. Empty lines were filled with 1× LDS sample buffer (10 μl). After the gel was run, it was washed thrice with DI water (100 ml) with shaking (15 minutes, 200 rpm). Coomassie staining was performed by shaker-incubating the gel with PAGEBlue protein stain (30 ml) (60 minutes, 200 rpm). Excess staining solution was removed, rinsed twice with DI water (100 ml) and destained with DI water (100 ml) (60 minutes, 200 rpm). The resulting gel was imaged and then further processed using ImageJ (Rasband, W.S., ImageJ, U. S. National Institutes of Health, Bethesda, Maryland, USA). TBEU-PAGE Native protein, conjugates and BNA standard were analysed under heat denaturing non-reducing and reducing conditions by TBEU-PAGE against an oligo ladder using a 15% TBE-Urea gel and TBE as running buffer (180V, ~60 minutes). Samples were prepared to 0.5 mg/ml, and BNA standard was prepared to 20 μg/ml, respectively, all comprising TBE Urea sample buffer and purified H2O as diluent. Samples and standards were heat treated for 3 minutes at 70°C and 10 μl added to each well, equating to 5 μg of protein and conjugate samples, and 0.2 μg of BNA, per lane. Oligo ladder reconstituted to 0.1 μg/band/ml in TE pH 7.5 (2 μl) was loaded without pre- treatment. After the gel was run, it was stained with freshly prepared ethidium bromide solution (1 μg/ml) with shaking (40 minutes, 200 rpm). The resulting gel was visualised by UV epi-illumination (254 nm), imaged and then further processed using ImageJ. MALDI-TOF-MS MALDI-TOF spectra were recorded on a MALDI-Mass Spectrometer (Bruker Ultrafex III). Typically, the sample dissolved in MilliQ water in nanomolar to micromolar range was spotted on the target (MTP 384 target plate polished steel T F, Bruker Daltons) using either super-DHB (99%, Fluka) or sinapinic acid (SA, 99%, Sigma-Aldrich) as the matrix dissolved in acetonitrile (MADLI-TOF-MS tested, Sigma) / 0.1% TFA (7:3 v/v) via the dried-droplet-method. PepMix (Peptide Calibration Standard, Bruker Daltons) or ProteMass (Protein Calibration Standard, Sigma-Aldrich) served as calibration standards. Release kinetics assay The SO1861 conjugate of interest was dissolved in an acetate buffer (20 mM, pH 4.0 or pH 5.0), a phosphate buffer (20 mM) or in a PBS buffer (pH 7.4) to a final concentration of 10 µM and incubated at either 20 ^C or 37 ^C. The release of SO1861 was followed over time by monitoring the decrease of the UPLC-UV4 peak area of the SO1861 conjugate of interest at different time points. Cell viability assay Cell viability was determined by an MTS-assay, performed according to the manufacturer’s instruction (CellTiter 96® AQueous One Solution Cell Proliferation Assay, Promega). Briefly, stock MTS solution was diluted 20x in DMEM without phenol red (PAN-Biotech GmbH) supplemented with 10% FBS (PAN-Biotech GmbH). Cells were washed once with 200 µL PBS per well, after which 100 µL diluted MTS solution per well was added. The plate was incubated for approximately 20- 30 minutes at 37 ^C. Subsequently, the optical density at 492 nm was measured on a Thermo Scientific Multiskan FC plate reader (Thermo Scientific). For quantification, the background signal of ‘medium only‘ wells was subtracted from the signal from all other wells before the ratio of untreated/treated cells was calculated by dividing the background corrected signal of treated wells by the background corrected signal of the untreated wells (multiplied by 100 for percentage viability relative to untreated reference wells). FACS analysis Cells were seeded in DMEM (PAN-Biotech GmbH) supplemented with 10% fetal calf serum (PAN- Biotech GmbH) and 1% penicillin/streptomycin (PAN-Biotech GmbH), at 500,000 c/plate in 10 cm dishes and incubated for 48 hrs (5% CO2, 37 ^C) until a confluency of 90% was reached. Next, the cells were trypsinized (TryplE Express, Gibco Thermo Scientific) to obtain a single cell suspension. 0.75 x 106 Cells were transferred to a 15 mL Falcon tube and centrifuged (1,400 rpm, 3 min). The supernatant was discarded while leaving the cell pellet submerged. The cell pellet was resuspended and cells were washed with 4 mL cold PBS (Mg2+ and Ca2+ free, 2% FBS). After washing, the cells were resuspended in 3 mL cold PBS (Mg2+ and Ca2+ free, 2% FBS) and divided equally over 3 round bottom FACS tubes (1 mL/tube). The cells were centrifuged again and resuspended in 200 µL cold PBS (Mg2+ and Ca2+ free, 2% FBS) or 200 µL antibody solution containing 5 µL antibody in 195 µL cold PBS (Mg2+ and Ca2+ free, 2% FBS). APC Mouse IgG1, κ APC anti-human EGFR (#352906, Biolegend) was used to stain the EGFR receptor. PE anti-human HER2 APC anti-human CD340 (erbB2/HER-2) (#324408 Biolegend ) was used to stain the HER2 receptor and PE Mouse IgG2a, κ Isotype Ctrl FC (#400212, Biolegend) was used as its matched isotype control. PE anti- human CD71 (#334106, Biolegend) was used to stain the CD71 receptor and PE Mouse IgG2a, κ Isotype Ctrl FC (#400212, Biolegend) was used as its matched isotype control. Samples were incubated for 30 min at 4 °C on a tube roller mixer. Afterwards, the cells were washed 3x with cold PBS (Mg2+ and Ca2+ free, 2% FBS) and fixated for 20 min at room temperature using a 2% PFA solution in PBS. Cells were washed 2x with cold PBS and resuspended in 250-350 µL cold PBS for FACS analysis. Data were acquired with a BD FACSCanto II flow cytometry system (BD Biosciences) and analyzed using FlowJo software. Table 1. Expression levels of EGFR, HER2 and CD71 of various cells
Figure imgf000166_0001
CMC determination The critical micellar concentration (CMC) of saponins derived from Saponaria officinalis (SO) was determined by the method of DeVendittis et al. (www.sciencedirect.com/science/article/pii/0003269781900063, doi.org/10.1016/0003- 2697(81)90006-3, Analytical Biochemistry, Volume 115, Issue 2, August 1981, Pages 278-286) as follows: the emission spectrum of 8-anilinonaphthalene-1-sulfonic acid (ANS) in either purified water (MQ) or DPBS (Dulbecco’s PBS +/+) was determined at dry weight concentrations of saponins ranging from 1 to 1400 µM to cover the range below and above the CMC. Above the CMC, the fluorescence yield of ANS increases and the wavelength of maximum emission decreases due to portioning of the fluorescent dye into micelles. Fluorescence yields were recorded on a Fluoroskan Ascent FL (Thermo Scientific) at an excitation wavelength of 355 nm and an emission wavelength of 460 nm.6 µg at a concentration of 75.86 µM of ANS were used per sample and measurement. Haemolysis assay Human red blood cells (RBCs) were isolated from a buffy coat using a Ficoll gradient. The RBC packed cells (~4-5 ml) were washed 2x with 50 ml DPBS without Ca2+/Mg2+ (PAN-Biotech GmbH). Cells were pelleted by centrifugation for 10 min, 800xg at RT. RBC were counted and resuspended at 500.000.000 c/ml in DPBS (without Ca2+/Mg2+), based on total cell count. SO1861-linker dilutions were prepared in DPBS (with Ca2+/Mg2+, PAN-Biotech GmbH), at 1.11x final strength. For positive lysis control, a 0.02% Triton-X100 solution was prepared in DPBS+/+.135 µl of all compounds was dispensed per well in a 96 well V-bottom plate. To this, 15 µl RBC suspension was added and mixed shortly (10 sec - 600 rpm). The plate was then incubated a further 30 min at RT, with gentle agitation. Next, the plate was spun for 10 min at 800xg to pellet the remaining unlysed RBC and 100-120 µl supernatant was transferred to a flat bottom 96 well plate. Subsequently, the OD at 405 nm was measured on a Thermo Scientific Multiskan FC plate reader (Thermo Scientific). For quantification the background signal of ‘DPBS+/+ only‘ wells was subtracted from all other wells before the percentage of hemolysis was calculated in comparison to 0.02% Triton-X100, by dividing the background corrected signal of treated wells over the background corrected signal of the 0.02% Triton-X100 wells (x 100). RNA isolation and gene expression analysis RNA from cells was isolated and analysed according to standard protocols (Biorad). The qPCR primers that were used are indicated in Table 2. Table 2. Primers used in qPCR are shown below:
Figure imgf000167_0001
Synthesis SO1861-SC-Mal (Figure 1) Intermediate 1: benzyl 4-(2-(tert-butoxycarbonyl)hydrazine-1-carbonyl)piperazine-1-carboxylate To a stirring solution of phosgene in toluene (20%, w/w, 15.8 mL, 30.0 mmol) at 0 ^C was added slowly (10 min) a solution of 1-Cbz-piperazine (1.93 mL, 10.0 mmol) in dichloromethane (25 mL) and DIPEA (3.83 mL, 22.0 mmol). The reaction mixture was stirred at room temperature. After 30 min, the reaction mixture was evaporated in vacuo and co-evaporated with dichloromethane (2 × 50 mL). Next, the residue was dissolved in dichloromethane (100 mL) and resulting solution was stirred at 0 ^C. A solution of Boc hydrazine (2.33 mL, 15.0 mmol) in dichloromethane (20 mL) and DiPEA (3.83 mL, 22.0 mL) was added and the reaction mixture was stirred overnight at room temperature. The reaction mixture was diluted with dichloromethane (100 mL) and the resulting solution was washed with 0.5 N potassium bisulphate solution (2 × 100 mL) and brine (100 mL), dried over Na2SO4, filtered and evaporated in vacuo. The residue was purified by flash chromatography (first by an ethyl acetate – heptane gradient, 5:95 (v/v) rising to 100% ethyl acetate followed by a flush with 10% methanol in DCM (v/v)) to give the title compound (2.42 g, 64%) as a white solid. Purity based on LC-MS 100%. LRMS (m/z): 279/323/401[M-99/M-55/M+23]1+ LC-MS r.t. (min): 1.271  Intermediate 2: tert-butyl 2-(piperazine-1-carbonyl)hydrazine-1-carboxylate To benzyl 4-(2-(tert-butoxycarbonyl)hydrazine-1-carbonyl)piperazine-1-carboxylate (2.42 g, 6.39 mmol) was added methanol (50 mL). The mixture was heated to obtain a clear solution. Next, palladium (10% on activated carbon, 50% wet with water, 1.50 g) was added and the resulting mixture was stirred under a hydrogen atmosphere by using a balloon. After 1 hour, the reaction mixture was filtered over celite and the filtrate evaporated in vacuo to give the title product (1.56 g, quant.) as a white solid. LRMS (m/z): 189/245 [M-55/M+1]1+  Intermediate 3: tert-butyl 2-(4-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoyl)piperazine-1- carbonyl)hydrazine-1-carboxylate 6-maleimidocaproic acid (810 mg, 3.84 mmol), tert-butyl 2-(piperazine-1-carbonyl)hydrazine-1- carboxylate (781 mg, 3.20 mmol), EDCI.HCl (735 mg, 3.84 mmol) and Oxyma Pure (591 mg, 4.16 mmol) were dissolved in a mixture of dichloromethane (25 mL) and DIPEA (835 µL, 4.80 mmol) and the reaction mixture was stirred at room temperature. After 2 hours, the reaction mixture was evaporated in vacuo and the residue was dissolved in ethyl acetate (50 mL). The resulting solution was washed with 0.5 N potassium bisulphate solution (50 mL), saturated sodium bicarbonate solution (2 × 50 mL) and brine (50 mL), dried over Na2SO4, filtered and evaporated in vacuo. The residue was purified by flash chromatography (DCM – 10% methanol in DCM (v/v) gradient 100:0 rising to 40:60) to give the title compound (634 mg, 45%) as a white solid. Purity based on LC- MS 97%.  LRMS (m/z): 338/382/460 [M-99/M-55/M+23]1+ LC-MS r.t. (min): 1.021  SO1861-SC-Mal (Figure 1) Chemical Formula: SO1861-SC-Mal: C98H151N5O49, Exact Mass: 2181.95 tert-butyl 2-(4-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoyl)piperazine-1-carbonyl)hydrazine- 1-carboxylate (25.0 mg, 57.1 µmol) was dissolved in a mixture of dichloromethane (500 µL) and TFA (500 µL) and the reaction mixture was stirred at room temperature. After 30 min the reaction mixture was evaporated in vacuo and co-evaporated with dichloromethane (3 × 5 mL) and methanol (5 mL). The residue and SO1861 (21.3 mg, 11.4 µmol) were dissolved in methanol (extra dry, 1.00 mL) and the resulting mixture was shaken for 1 min and left standing at room temperature. After 4 hours, the reaction mixture was subjected to preparative MP-LC.2 Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to yield the title compound (13.7 mg, 55%) as a white fluffy solid. Purity based on LC-MS 97%. LRMS (m/z): 2181 [M-1]1- LC-MS r.t. (min): 2.133 SO1861-SC (Figure 2A) Morpholine-4-carbohydrazide (8.1 mg, 56 µmol) and SO1861 (21.3 mg, 11.4 µmol) were dissolved in methanol (extra dry, 1.00 mL). Then 50 µLTFA was added and the resulting mixture was shaken for 1 min and left standing at room temperature. After 4 hours, the reaction mixture was subjected to preparative MP-LC.2 Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to yield the title compound (13.8 mg, 61%) as a white fluffy solid. Purity based on LC-MS 96%. LRMS (m/z): 1988 [M-1]1- SO1861-SC-Mal (blocked) (Figure 2B) SO1861-SC-Mal (3.63 mg, 1.66 µmol) was dissolved in a solution of 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 500 µL). Directly afterwards 2-mercaptoethanol (0.466 µL, 6.65 µmol) was added. The reaction mixture was shaken for 1 min and left standing at room temperature. After 30 min, the reaction mixture was subjected to preparative MP-LC.2 Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to yield the title compound (2.35 mg, 63%) as a white fluffy solid. Purity based on LC-MS 96%. LRMS (m/z): 2260 [M-1]1- LC-MS r.t. (min): 3.534 SO1861-EMCH synthesis (Figure 3) To SO1861 (121 mg, 0.065 mmol) and EMCH.TFA (110 mg, 0.325 mmol) was added methanol (extra dry, 3.00 mL) and TFA (0.020 mL, 0.260 mmol). The reaction mixture stirred at room temperature. After 1.5 hours, the reaction mixture was subjected to preparative MP- LC.1 Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (120 mg, 90%) as a white fluffy solid. Purity based on LC-MS 96%. LRMS (m/z): 2069 [M-1]1- LC-MS r.t. (min): 1.084 Dendron(SO1861)4 synthesis (Figure 4) Intermediate 4: (Figure 4 a) di-tert-butyl (((6-azidohexanoyl)azanediyl)bis(ethane-2,1-diyl))dicarbamate 6-azidohexanoic acid (0.943 g, 6.00 mmol), EDCI.HCl (1.21 g, 6.30 mmol) and Oxyma Pure (0.938 g, 6.60 mmol) were dissolved in DMF (10.0 mL) and the mixture was stirred for 5 min. Next, a solution of di-tert-butyl (azanediylbis(ethane-2,1-diyl))dicarbamate (1.82 g, 6.00 mmol) in DMF (5.00 mL) was added and the reaction mixture was stirred at room temperature. After 5 hours, the reaction mixture was evaporated in vacuo and the residue was dissolved in ethyl acetate (50 mL). The resulting solution was washed with 1N potassium bisulphate solution (50 mL), saturated sodium bicarbonate solution (2 × 50 mL) and brine (50 mL), dried over Na2SO4, filtered and evaporated in vacuo. The residue was purified by flash chromatography (ethyl acetate - heptane gradient, 10:90 rising to 100:0) to give the title compound (2.67 g, 100%) as a white solid. Purity based on LC-MS 98%. LRMS (m/z): 287/343/465 [M-155/M-99/M+23]1+ LC-MS r.t. (min): 2.022A Intermediate 5: (Figure 4 a) N,N-bis(2-aminoethyl)-6-azidohexanamide dihydrochloride To di-tert-butyl (((6-azidohexanoyl)azanediyl)bis(ethane-2,1-diyl))dicarbamate (2.66 g, 6.00 mmol) was added HCl in isopropanol (5-6 N, 20.0 mL, 110 mmol) and the reaction mixture was stirred at room temperature. After 4 hours, the reaction mixture was evaporated in vacuo and the resulting crude product was co-evaporated with DCM (3 × 20 mL) to give the crude title product (1.49 g, 79%) as a white solid. LRMS (m/z): 243 [M+1]1+ Intermediate 6: (Figure 4 a) tetra-tert-butyl ((5S,5'S)-((((6-azidohexanoyl)azanediyl)bis(ethane-2,1- diyl))bis(azanediyl))bis(6-oxohexane-6,1,5-triyl))tetracarbamate To a solution of N,N-bis(2-aminoethyl)-6-azidohexanamide dihydrochloride (1.19 g, 3.76 mmol) in DMF (30.0 mL) and DIPEA (2.62 mL, 15.1 mmol) was added Boc-Lys(Boc)-ONp (3.69 g, 7.90 mmol) and the mixture was stirred at room temperature overnight. The reaction mixture was evaporated in vacuo and the residue was dissolved in ethyl acetate (100 mL). The resulting solution was washed with 1N potassium bisulphate solution (100 mL) and saturated sodium bicarbonate solution (5 × 100 mL), dried over Na2SO4, filtered and evaporated in vacuo. The residue was purified by flash chromatography (DCM - methanol/DCM (1/9, v/v) gradient 100:0 rising to 0:100) to give the give the title product (3.07 g, 91%) as a slightly yellowish solid. Purity based on LC-MS 94%. LRMS (m/z): 800/900/922 [M-99/M+1/M+23]1+ LC-MS r.t. (min): 2.172A Intermediate 7: (Figure 4 b) 4-nitrophenyl 3-(acetylthio)propanoate 4-Nitrophenyl trifluoroacetate (5.17 g, 22.0 mmol) and 3-(Acetylthio)propionic Acid (2.96 g, 20.0 mmol) were dissolved in DCM (50.0 mL). Next, DIPEA (6.97 mL, 40.0 mmol) was added and the reaction mixture was stirred at room temperature overnight. The reaction mixture was evaporated in vacuo and the residue was dissolved in ethyl acetate (50 mL). The resulting solution was washed with 1N potassium bisulphate solution (50 mL), saturated sodium bicarbonate solution (5 × 50 mL) and brine (50 mL), dried over Na2SO4, filtered and evaporated in vacuo. The residue was purified by flash chromatography (DCM - methanol/DCM (1/9, v/v) gradient 100:0 rising to 0:100) to give the give the title product (4.90 g, 91%) as a slightly yellowish solid. Purity based on LC-MS 99%. LRMS (m/z): 292 [M+23]1+ LC-MS r.t. (min): 1.942A Intermediate 8: (Figure 4 b) (S)-2,6-diamino-N-(2-(6-azido-N-(2-((S)-2,6- diaminohexanamido)ethyl)hexanamido)ethyl)hexanamide tetrahydrochloride tetra-tert-butyl ((5S,5'S)-((((6-azidohexanoyl)azanediyl)bis(ethane-2,1-diyl))bis(azanediyl))bis(6- oxohexane-6,1,5-triyl))tetracarbamate (1.80 g, 2.00 mmol) was dissolved in HCl in isopropanol (5- 6N, 50.0 ml, 275 mmol) and the reaction mixture was stirred at room temperature overnight. The reaction mixture was evaporated in vacuo and the resulting crude product was co-evaporated with DCM (3 × 20 mL) to give the crude title product as a white solid. LRMS (m/z): 250 [M+2]2+, 500 [M+1]1+ Intermediate 9: (Figure 4 b) (2S)-2,6-bis[3-(acetylsulfanyl)propanamido]-N-[2-(6-azido-N-{2-[(2S)-2,6-bis[3- (acetylsulfanyl)propanamido]hexanamido]ethyl}hexanamido)ethyl]hexanamide To a solution of (S)-2,6-diamino-N-(2-(6-azido-N-(2-((S)-2,6- diaminohexanamido)ethyl)hexanamido) ethyl)hexanamide tetrahydrochloride (1.29 g, 2.00 mmol) in DMF (30 mL) and DIPEA (3.48 mL, 20.0 mmol) was added 4-nitrophenyl 3- (acetylthio)propanoate (2.26 g, 8.40 mmol) and the reaction mixture was stirred at room temperature over the weekend. The reaction mixture was evaporated in vacuo and the residue was dissolved in DCM/methanol (95:5, v/v, 100 mL). The resulting solution was washed with 1N potassium bisulphate solution (100 mL), 1 N sodium hydroxide solution (3 × 100 mL) and brine (100 mL), dried over Na2SO4, filtered and evaporated in vacuo. The residue was purified by flash chromatography (DCM - methanol/DCM (1/9, v/v) gradient 100:0 rising to 0:100) to give the title product (1.33 g, 65%) as a white solid. On LC-MS an impurity (15%) was found with m/z values corresponding to the product with one deprotected thioacetate group. The impurity was formed during or after work-up. Purity based on LC-MS 85%. LRMS (m/z): 510 [M+2]2+, 1019/1041 [M+1/M+23]1+ LC-MS r.t. (min): 1.862B Intermediate 10: (Figure 4 c) N,N'-((9S,19S)-14-(6-aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18- trioxo-4,11,14,17-tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide) formate Intermediate 9 (102 mg, 0.100 mmol) was dissolved in methanol (1.00 ml). Next, a freshly prepared 1 N Sodium hydroxide solution (0.440 ml, 0.440 mmol) was added and the reaction mixture was stirred at room temperature. After 30 min a 1.0 M trimethylphosphine solution in THF (0.500 ml, 0.500 mmol) was added and the resulting mixture was stirred at room temperature. After 30 min, the reaction mixture was evaporated in vacuo and co-evaporated with methanol (2 × 10 mL). The residue was dissolved in a mixture of methanol/water (9:1, v/v, 1.00 mL) and the resulting solution was subjected to preparative MP-LC.2 Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (75.6 mg, 87%) as a colorless sticky oil. Purity based on LC-MS 96%. LRMS (m/z): 513 [M+2]2+, 825 [M+1]1+ LC-MS r.t. (min): 1.422A Intermediate 11 and 12: (Figure 4 d) The conjugation of SO1861 to the dendron to yield Dendron(SO1861)4-amine was performed for both SO1861-EMCH and SO1861-SC-maleimide. Intermediate 11 Dendron(EMCH-SO1861)4-amine (Figure 4 e) N,N'-((9S,19S)-14-(6-aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo- 4,11,14,17-tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide) formate (2.73 mg, 3.13 µmol) was dissolved in a mixture of 20 mM NH4HCO3 with 0.5 mM TCEP/acetonitrile (3:1, v/v, 3.00 mL). Next, SO1861-EMCH (29.2 mg, 0.014 mmol) was added and the reaction mixture was stirred at room temperature. After 1.5 hours, the reaction mixture was subjected to preparative LC- MS.3B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (12.3 mg, 43%) as a white fluffy solid. Purity based on LC-MS 97%. LRMS (m/z): 1517 [M-6]6-, 1821 [M-5]5-, 2276 [M-4]4- LC-MS r.t. (min): 4.395A Intermediate 12 Dendron-(semicarbazone-SO1861)4-amine (Figure 4 e) N,N'-((9S,19S)-14-(6-aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo- 4,11,14,17-tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide) formate (2.73 mg, 3.13 µmol, molecule 38) was dissolved in a mixture of 1M NaOH and MeOH (1:1, v/v, 3.00 mL) and stirred for 30 min. Next, 5 mL of Trimethylphosphine (9.5 mg, 125 µmol) dissolved in THF was added and the mixture was stirred for 30 min. Next, SO1861-SC-Mal (30.54 mg, 0.014 mmol, molecule 37) dissolved in 20 mM NH4HCO3 with acetonitrile (3:1, v/v, 3.00 mL) was added and the reaction mixture was stirred at room temperature. After 1.5 hours, the reaction mixture was subjected to preparative LC-MS.3B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (19 mg, 64 %) as a white fluffy solid. Purity based on LC-MS 95%. MS (m/z): 9553 [M+H]+ Dendron-(SO1861)4-azide Dendron(EMCH-SO1861)4-azide (Figure 4 f) Dendron-(EMCH-SO1861)4-amine (6.81 mg, 0.748 µmol) and 2,5-dioxopyrrolidin-1-yl 1-azido- 3,6,9,12-tetraoxapentadecan-15-oate (2.90 mg, 7.48 µmol) were dissolved in DMF(1.00 mL). Next, DIPEA (1.302 µL, 7.48 µmol) was added and the mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC- MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (5.86 mg, 84%) as a white fluffy solid. Purity based on LC-MS 90%. LRMS (m/z): 2344 [M-4]4- LC-MS r.t. (min): 4.785B Dendron(semicarbazone-SO1861)4-azide (Figure 4 f): Dendron-(semicarbazone-SO1861)4-amine (7.1 mg, 0.748 µmol, molecule 39) and 2,5- dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate (2.90 mg, 7.48 µmol, molecule 18) were dissolved in DMF (1.00 mL). Next, DIPEA (1.302 µL, 7.48 µmol) was added and the mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (6.4 mg, 87%) as a white fluffy solid. Purity based on LC-MS 93%. MS (m/z): 9826 [M+H]+ Dendron-(SO1861)4-maleimide1 (Figure 4 g) The synthesis of Dendron(SO1861)4-maleimide1 was performed for both saponin-dendron conjugates Dendron(EMCH-SO1861)4-amine and Dendron(semicarbazone-SO1861)4-amine. The following synthesis is exemplary described for Dendron-(EMCH-SO1861)4-maleimide1. Dendron-(EMCH-SO1861)4-maleimide1 (Figure 4 g) Dendron(SO1861)4-amine (8.12 mg, 0.891 µmol) and 2,5-dioxopyrrolidin-1-yl 1-(2,5-dioxo-2,5- dihydro-1H-pyrrol-1-yl)-3,6,9,12-tetraoxapentadecan-15-oate (3.94 mg, 8.91 µmol) were dissolved in DMF(1.00 mL). Next, DIPEA (1.55 µL, 8.91 µmol) was added and the mixture was shaken for 1 min and left standing at room temperature. After 3 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (6.76 mg, 80%) as a white fluffy solid. Purity based on LC-MS 66%. LRMS (m/z): 2358 [M-4]4- LC-MS r.t. (min): 2.136C Dendron-(SO1861)4-maleimide2 (Figure 4 h) The synthesis of Dendron(SO1861)4-maleimide1 was performed for both saponin-dendron conjugates Dendron(EMCH-SO1861)4-amine and Dendron-(semicarbazone-SO1861)4-amine. The following synthesis is exemplary described for Dendron(EMCH-SO1861)4-maleimide2. Dendron(SO1861)4-maleimide2 (Figure 4 h) Intermediate 9 (5.10 mg, 5.00 µmol) was dissolved in methanol (100 µL). Next, a freshly prepared 1 N Sodium hydroxide solution (22.0 µL, 22.0 µmol) was added and the mixture was shaken for 1 min and left standing at room temperature. After 30 min, a 1.0 M trimethylphosphine solution in THF (25.0 µL, 25.0 µmol) was added and the resulting mixture was shaken for 1 min and left standing at room temperature. After a further 30 min, the reaction mixture was evaporated in vacuo and co- evaporated with methanol (2 × 5 mL). The resulting residue was dissolved in a mixture of 20 mM NH4HCO3 with 0.5 mM TCEP/acetonitrile (3:1, v/v, 3.242 mL). From this solution, 1000 µL was directly added to SO1861-EMCH (14.4 mg, 6.94 µmol, 4.5 equiv. compared to the scaffold) and the mixture was shaken for 1 min and left standing at room temperature. After 10 min, the reaction mixture was lyophilized overnight. To the resulting residue 2,5-Dioxopyrrolidin-1-yl 3-(2-(2-(3-(2,5- dioxo-2h-pyrrol-1(5h)-yl)propanamido)ethoxy)ethoxy)propanoate (5.84 mg, 0.014 mmol) and DMF (1.00 mL) were added. Next, DIPEA (2.39 µL, 0.014 mmol) was added and the suspension was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (10.9 mg, 85%) as a white fluffy solid. Purity based on LC-MS 80%. LRMS (m/z): 2354 [M-4]4- LC-MS r.t. (min): 4.165B Dendron-(SO1861)8 synthesis Intermediate 13: (Figure 5 a) tert-butyl N-[(1S)-1-{[(1S)-1-{[2-(6-azido-N-{2-[(2S)-2,6-bis[(2S)-2,6-bis({[(tert- butoxy)carbonyl]amino})hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5- [(2S)-2,6-bis({[(tert-butoxy)carbonyl]amino})hexanamido]pentyl]carbamoyl}-5-{[(tert- butoxy)carbonyl]amino}pentyl]carbamate (S)-2,6-diamino-N-(2-(6-azido-N-(2-((S)-2,6- diaminohexanamido)ethyl)hexanamido)ethyl)hexanamide tetrahydrochloride (964 mg, 1.50 mmol) was dissolved in DMF (25.0 mL) and triethylamine (2.08 mL, 15.0 mmol). Next, Boc-Lys(Boc)-ONp (3.36 g, 7.18 mmol) was added and the reaction mixture was stirred at room temperature overnight. The reaction mixture was evaporated in vacuo and the residue was purified by flash chromatography (DCM - methanol/DCM (1/9, v/v) gradient 100:0 rising to 0:100) to give the title product (2.71 g, 100%) as a white solid. Purity based on LC-MS 97%. LRMS (m/z): 807 [M-198]2+ LC-MS r.t. (min): 2.352B Intermediate 14: (Figure 5 b) (2S,2'S)-N,N'-((5S,15S,22S)-22,26-diamino-10-(6-azidohexanoyl)-15-((S)-2,6- diaminohexanamido)-6,14,21-trioxo-7,10,13,20-tetraazahexacosane-1,5-diyl)bis(2,6- diaminohexanamide) octahydrochloride Intermediate 13 (2.71 g, 1.50 mmol) was dissolved in HCl in isopropanol (5-6N, 25.0 ml, 138 mmol) and the reaction mixture was stirred at room temperature overnight. Next, the reaction mixture was evaporated in vacuo and the resulting crude product was co-evaporated with DCM (3 × 20 mL) to give the crude title product as a white solid. LRMS (m/z): 203/254 [M-200/M+4]4+, 338 [M+3]3+, 507 [M+2]2+, 1012 [M+1]1+ Intermediate 15: (Figure 5 c) (2S)-2,6-bis[3-(acetylsulfanyl)propanamido]-N-[(1S)-1-{[2-(6-azido-N-{2-[(2S)-2,6-bis[(2S)- 2,6- bis[3- (acetylsulfanyl)propanamido]hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl} -5-[(2S)-2,6-bis[3-(acetylsulfanyl)propanamido]hexanamido]pentyl]hexanamide  To (2S,2'S)-N,N'-((5S,15S,22S)-22,26-diamino-10-(6-azidohexanoyl)-15-((S)-2,6- diaminohexanamido)-6,14,21-trioxo-7,10,13,20-tetraazahexacosane-1,5-diyl)bis(2,6- diaminohexanamide) octahydrochloride (300 mg, 0.230 mmol) was added DMF (20.0 mL), triethylamine (320 µl, 2.30 mmol) and 4-nitrophenyl 3-(acetylthio)propanoate (595 mg, 2.21 mmol). The resulting suspension was sonicated at 60 °C for 30 min and left stirring at room temperature overnight. The reaction mixture was evaporated in vacuo and the residue was purified by first performing flash chromatography (DCM - methanol/DCM (1/9, v/v) gradient 100:0 rising to 0:100), followed by preparative MP-LC2 to give the title product (70 mg, 15%) as a white solid. Purity based on LC-MS 100%. LRMS (m/z): 685 [M+3]3+ LC-MS r.t. (min): 1.912A Intermediate 16: (Figure 5 d) (2S)-N-[(1S)-1-{[2-(6-amino-N-{2-[(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5- [(2S)-2,6-bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3- sulfanylpropanamido)hexanamide formate Intermediate 15 (10.0 mg, 4.87 µmol) was dissolved methanol (200 µL). Next, a freshly prepared 1 N Sodium hydroxide solution (42.9 µL, 0.043 mmol) was added and the resulting mixture was shaken for 1 min and left standing at room temperature. After 30 min, a 1.0 M trimethylphosphine solution in THF (24.4 µL, 0.024 mmol) was added and the resulting mixture was shaken for 1 min and left standing at room temperature. After 30 min, the reaction mixture was diluted with water (1 mL) and directly subjected to preparative MP- LC.2 Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (4.02 mg, 48%) as a white fluffy solid. LRMS (m/z): 564 [M+3]3+, 846 [M+2]2+ LC-MS r.t. (min): 1.542C Dendron-(SO1861)8-amine (Figure 4 d) The conjugation of SO1861 to the dendron to yield Dendron-(SO1861)8-amine was performed for both SO1861-EMCH and SO1861-SC-maleimide. Intermediate 17: (Figure 5 e) Dendron(EMCH--SO1861)8-amine Intermediate 16 (0.52 mg, 0.299 µmol) and SO1861-EMCH (29.2 mg, 0.014 mmol) were dissolved in a mixture of 20 mM NH4HCO3 with 0.5 mM TCEP/acetonitrile (3:1, v/v, 1.00 mL) and the resulting mixture was shaken for 1 min and left standing at room temperature. After 30 min, TCEP (0.30 mg, 1.05 µmol) was added and the reaction mixture was shaken for 1 min. Next, the mixture was directly subjected to preparative LC-MS.3B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (2.17 mg, 40%) as a white fluffy solid. Purity based on LC-MS 97%. LRMS (m/z): 2282 [M-8]8-, 2607 [M-7]7- LC-MS r.t. (min): 4.415A Intermediate 18: (Figure 5 e) Dendron(semicarbazone-SO1861)8-amine (2S)-N-[(1S)-1-{[2-(6-amino-N-{2-[(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate (0.61 mg, 0.299 µmol, molecule 43) was dissolved in a mixture of 1M NaOH and MeOH (1:1, v/v, 3.00 mL) and stirred for 30 min. Next, 5 mL of Trimethylphosphine (2 mg, 24 µmol) dissolved in THF was added and the mixture was stirred for 30 min. Next, SO1861-SC-Mal (30.54 mg, 0.014 mmol, molecule 37) dissolved in 20 mM NH4HCO3 with acetonitrile (3:1, v/v, 3.00 mL) was added and the reaction mixture was stirred at room temperature. After 1.5 hours, the reaction mixture was subjected to preparative LC-MS.3B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (4.6 mg, 81 %) as a white fluffy solid. Purity based on LC-MS 95%. MS (m/z): 19146 [M+H]+ Dendron-(SO1861)8-azide (Figure 5 f): The synthesis of Dendron(SO1861)8-azide was performed at both saponin-dendron conjugates Dendron-(EMCH-SO1861)8-amine and Dendron-(semicarbazone-SO1861)8-amine. The following synthesis is exemplary described for Dendron-(semicarbazone-SO1861)8-azide. Dendron-(semicarbazone-SO1861)8-azide Dendron-(semicarbazone-SO1861)8-amine (5.4 mg, 0.28 µmol, molecule 44) and 2,5- dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate (1.1 mg, 2.8 µmol, molecule 18) were dissolved in DMF(1.00 mL). Next, DIPEA (1.302 µL) was added and the mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (4.35 mg, 80%) as a white fluffy solid. Purity based on LC-MS 93%. MS (m/z): 19420 [M+H]+ Dendron(SO1861)8-maleimide1 (Figure 5 g): The synthesis of Dendron(SO1861)8- maleimide1 was performed at both saponin-dendron conjugates Dendron(EMCH-SO1861)8-amine and Dendron(semicarbazone-SO1861)8-amine. The following synthesis is exemplary described for Dendron(semicarbazone-SO1861)8-maleimide1. Dendron(SO1861)8-amine (17 mg, 0.891 µmol) and 2,5-dioxopyrrolidin-1-yl 1-(2,5-dioxo-2,5- dihydro-1H-pyrrol-1-yl)-3,6,9,12-tetraoxapentadecan-15-oate (3.94 mg, 8.91 µmol) were dissolved in DMF(1.00 mL). Next, DIPEA (1.55 µL, 8.91 µmol) was added and the mixture was shaken for 1 min and left standing at room temperature. After 3 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (13.2 mg, 76%) as a white fluffy solid. Purity based on LC-MS 71%. MS: 19473 [M+H]+ Dendron(SO1861)8-maleimide2 (Figure 5 h): The synthesis of Dendron(SO1861)8-maleimide2 was performed at both saponin-dendron conjugates Dendron(EMCH-SO1861)8-amine and Dendron(semicarbazone-SO1861)8-amine. The following synthesis is exemplary described for Dendron(semicarbazone-SO1861)8-maleimide2. Dendron(SO1861)8-amine (27 mg, 1.4 µmol) and 2,5-Dioxopyrrolidin-1-yl 3-(2-(2-(3-(2,5-dioxo-2h- pyrrol-1(5h)-yl)propanamido)ethoxy)ethoxy)propanoate (5.84 mg, 0.014 mmol) were dissolved in DMF (1.00 mL). Next, DIPEA (2.39 µL, 0.014 mmol) was added and the suspension was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (16 mg, 60 %) as a white fluffy solid. Purity based on LC-MS 81 %. MS: 19456 [M+H]+ Mab-Saporin conjugates Custom trastuzumab-saporin, cetuximab-saporin or CD71mab-saporin conjugates were produced and purchased from Advanced Targeting Systems (San Diego, CA). Antibody-(SC-SO1861)n , Antibody-(EMCH-SO1861)n conjugates Trastuzumab, cetuximab, are referred hereafter as “Ab”. Ab was conjugated to SO18161-EMCH or SO1861-semicarbazone-Mal (SO1861-SC-Mal) via Michael-type thiol-ene conjugation reaction at DAR 4. The SO1861-EMCH and SO1861-SC-Mal molecule obtains a labile (L) pH-sensitive bond between its structure and its maleimide function generating a labile bond between the SO1861 and Ab. The procedure is exemplary described for cetuximab-(SC-SO1861)4: to a solution of cetuximab (40 mg, 8.0 ml) was added 10 μl/ml each of Tris concentrate (127 mg/ml, 1.05 M), Tris.HCl concentrate (623 mg/ml, 3.95 M) and EDTA-Na2 concentrate (95 mg/ml, 0.26 M) to give a 50 mM TBS, 2.5 mM EDTA buffer pH 7.5. To cetuximab divided into four portions (each of 9.73 mg, 4.864 mg/ml, 65 nmol) was added an aliquot of freshly prepared TCEP solution (0.5 – 2.0 mg/ml, 1.15 – 7.02 mole equivalents, 75 – 455 nmol), the mixtures vortexed briefly then incubated for 300 minutes at 20 ^C with roller-mixing. After incubation (prior to addition of SO1861-SC-Mal), a ca.1 mg (0.210 ml) aliquot of Ab-SH was removed from each mixture and purified by gel filtration using a zeba spin desalting column into TBS pH 7.5. These aliquots were characterized by UV-vis analysis and Ellman’s assay. To each of the bulk Ab-SH was added an aliquot of freshly prepared SO1861-SC- Mal solution (2 mg/ml, 1.3 mole equivalents per ‘thiol’, 0.15 – 0.61 µmol, 0.16 – 0.63 ml), the mixtures vortexed briefly then incubated for 120 minutes at 20 ^C. Besides each conjugation reaction, two aliquots of desalted Ab-SH (0.25 mg, 1.67 nmol) were reacted with NEM (1.3 mole equivalents per ‘thiol’, 4.3 – 17.4 nmol, 2.2 – 8.7 μl of a 0.25 mg/ml solution) or TBS pH 7.5 buffer (2.2 – 8.7 μl) for 120 minutes at 20 ^C, as positive and negative controls, respectively. After incubation (prior to addition of NEM), a 0.200 ml aliquot of Ab – SC-SO1861 mixture was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterized by UV-vis and alongside positive and negative controls were characterized by Ellman’s assay to obtain SO1861-SC incorporations. To the bulk Ab- SC-SO1861 mixture was added an aliquot of freshly prepared NEM solution (2.5 mg/ml, 2.5 – 10 mole equivalents, 0.15 – 0.58 µmol) and the mixtures purified by zeba spin desalting columns eluting with DPBS pH 7.5 to give purified cetuximab – (SC-SO1861) conjugates. The products were normalized to 2.5 mg/ml and filtered to 0.2 μm prior to dispensing for biological evaluation. Antibody-(S-HSP27BNA)n To an aliquot of trastuzumab (5.00 mg, 3.3 × 10-5 mmol, 2.5 mg/ml) was added an aliquot of freshly prepared SMCC solution (2.00 mg/ml, 8.56 mole equivalents, 28.5 × 10-5 mmol) in DMSO, the mixture vortexed briefly then incubated for 60 minutes at 20 ^C with roller-mixing. After, the reaction was quenched by the addition of an aliquot of a freshly prepared glycine solution (10.0 mg/ml, 5.0 mole equivalents, 1.4 × 10-3 mmol) in DPBS pH 7.5. Tras-SMCC (5.15 mg, 3.4 × 10-5 mmol, 2.127 mg/ml, Tras:SMCC = 4.4) was obtained after gel filtration using a zeba 10 ml spin column eluting with TBS pH 7.5, and characterised by UV-vis spectrophotometry and SAMSA colorimetric assay. BNA lyophilisate was reconstituted to 10 mg/ml using TBS pH 7.5 and analysed by UV-vis spectrophotometry. To (protected) BNA (9.5 mg, 1.6 × 10-3 mmol, 9.59 mg/ml) was added an aliquot of freshly prepared TCEP solution (50.0 mg/ml, 10 mole equivalents, 16.3 × 10-3 mmol) in TBS pH 7.5, the mixture briefly vortexed then incubated for 60 minutes at 37 °C with roller-mixing. After, the mixture was desalted using a PD10 G25 desalting column eluted with TBS pH 7.5, followed by repeated washing via diafiltration using vivaspin T43K MWCO filters (3,000, 20 ^C, ~15 minutes) and TBS pH 7.5 (seven cycles in total) to remove residual TCEP. BNA-SH (7.90 mg, 1.3 × 10-3 mmol, 3.098 mg/ml, BNA:SH = 1.2) was characterised by UV-vis spectrophotometry and Ellman’s colorimetric assay. To Tras-SMCC (4.93 mg, 3.3 × 10-5 mmol, 2.127 mg/ml) was added an aliquot of BNA-SH (8.0 mole equivalents, 26.3 × 10-5 mmol, 3.098 mg/ml, 0.499 ml), the mixture vortexed briefly then incubated overnight at 20 ^C. After ca. 16 hours, the conjugate was purified by gel filtration using a 1.6 × 35 cm Sephadex G50M column eluted with DPBS pH 7.5. The conjugate was collected, pooled and concentrated to ca.1 ml. The concentrate was analysed by BCA assay to ascertain antibody concentration and then by UV-vis spectrophotometry to ascertain a combined mass based extinction coefficient ε value for the conjugate and incorporation of BNA. The product was normalised to 2.0 mg/ml and spin-filtered to 0.2 µm. The result was trastuzumab – BNA conjugate (2.0 mg/ml, 1.1 ml, 48%, BNA to mAB ratio = 2.2, purity = 99.0%). Synthesis of antibody(-L-SC-SO1861)4 – (S-HSP27BNA)2, Antibody(-L-EMCH-SO1861)4 – (S- HSP27BNA)2 conjugates Trastuzumab, cetuximab, are referred hereafter as “Ab”. Ab was conjugated to SO18161-EMCH or SO1861-semicarbazone-Mal (SO1861-SC-Mal) via Michael-type thiol-ene conjugation reaction at DAR 4. The SO1861-EMCH and SO1861-SC-Mal molecule obtains a labile (L) pH sensitive bond between its structure and its maleimide function generating a labile bond between the SO1861 and Ab. The procedure is exemplary described for conjugate cetuximab-(SC-SO1861)4-(BNA)2 (cetuximab-(SC-SO1861)-(BNA) (DAR4/DAR2) comprising four copies of the SO1861 and two copies of the BNA. This exemplary conjugate is tested for its influence on HSP27 expression in A431 cells (See Figure 22). To an aliquot of Cet-(SC- SO1861)4 (24.7 mg, 1.65 × 10-4 mmol, 2.50 mg/ml) was added an aliquot of freshly prepared PEG4-SPDP solution (5.00 mg/ml, 3.31 mole equivalents, 5.45 × 10-4 mmol), the mixture vortexed briefly then incubated for 60 minutes at 20 °C with roller-mixing. After incubation, the reaction was quenched by the addition of freshly prepared glycine solution (10.0 mg/ml, 16 mole equivalents, 2.64 × 10-3 mmol), the mixture vortexed briefly then incubated for >15 minutes at 20 °C with roller-mixing. The conjugate was purified by 2.6 × 26 cm Sephadex G50M column eluted with TBS pH 7.5 and analysed by UV-vis to give purified Cet-(SC- SO1861)4 – SPDP (23.7 mg, 96%, 1.32 mg/ml, SPDP per Cet ratio = 2.5). Cet-(SC-S SO1861)4 -SPDP was stored at 2-8°C in the dark until required. Separately, an aliquot of Thiol HSP27BNA (4.16 mg, 7.08 × 10-4 mmol, 10.80 mg/ml) reconstituted using TBS pH 7.5 was added to an aliquot of freshly prepared THPP solution (50 mg/ml, 10 mole equivalents, 7.08 × 10-3 mmol, 29.5 μl). The mixture was vortexed briefly, then incubated for 60 minutes at 37 °C with roller-mixing. After incubation, the BNA was purified by PD10 Sephadex G25M column, eluted with TBS pH 7.5, to afford BNA-SH (3.15 mg, 76%, SH to HSP27BNA ratio = 0.88). To an aliquot of Cet-(SC- SO1861)4 – SPDP (10.01 mg, 6.67 × 10-5 mmol, 1.32 mg/ml) was added an aliquot of BNA-SH (2.10 mg/ml, 4.0 mole equivalents, 2.67 × 10-4 mmol, 0.747 ml), the mixture vortexed briefly then incubated for 3 hours at 20 °C and overnight at 5 °C with roller-mixing. Reaction progression was measured by PDT displacement. After ca.18 hours, the conjugate mixture was again UV analysed to confirm PDT displacement by HSP27BNA and was then purified using a 2.6 × 26 cm Sephadex G50M column eluted with DPBS pH 7.5 to give purified Cet-(SC- SO1861)4 – HSP27BNA conjugate. The aliquot was analysed by BCA colorimetric assay and assigned a new molar absorptivity, then concentrated and normalised to 2.5 mg/ml, filtered to 0.2μm and then dispensed into an aliquot for characterisation (retain) and two aliquots for product testing, one supplied refrigerated and the other frozen. The result was a Cet-(SC-SO1861)4 – HSP27BNA conjugate (total yield = 8.75 mg, 87%, HSP27BNA to Cet: ratio = 1.4). HSP27BNA, oligonucleotide sequences HSP27 (5’-GGCacagccagtgGCG-3’) [SEQ ID NO: 1], more specifically BNANC, modified from Zhang et al. (2011) [Y Zhang, Z Qu, S Kim, V Shi, B Liao1, P Kraft, R Bandaru, Y Wu, LM Greenberger and ID Horak, Down-modulation of cancer targets using locked nucleic acid (LNA)-based antisense oligonucleotides without transfection, Gene Therapy (2011) 18, 326–333]), BNANC oligos were ordered with 5’-Thiol C6 linker at Bio-Synthesis Inc (Lewisville, Texas), with BNA bases in capitals, and fully phosphorothioated backbones. hCD71mab-EMCH-SO1861 hCD71mab was desalted into TBS pH 7.5 buffer and then normalised to 3 mg/ml. To an aliquot of hCD71mab (7.52 mg, 3.007 mg/ml, 5.1 × 10-5 mmol) was added an aliquot of freshly prepared TCEP solution (2.0 mg/ml, 4 mole equivalents, 20.4 × 10-5 mmol), the mixtures vortexed briefly then incubated for 210 minutes at 20 °C with roller-mixing. After incubation (prior to addition of SO1861- EMCH), a ca.1 mg (0.340 ml) aliquot of hCD71mab-SH was removed from the mixture and purified by gel filtration using a zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV-vis analysis and Ellman’s assay (SH to hCD71 ratio = 3.9). To the bulk hCD71mab-SH was added an aliquot of freshly prepared SO1861-EMCH solution (2 mg/ml, 2.0 mole equivalents per ‘thiol’, 4.1 × 10-4 mmol), the mixtures vortexed briefly then incubated for 120 minutes at 20 °C. Besides the conjugation reaction, two aliquots of desalted hCD71mab-SH (0.25 mg, 1.67 × 10-6 mmol) were reacted with NEM (2.0 mole equivalents per ‘thiol’, 13 × 10-6 mmol, 6 μl of a 0.25 mg/ml solution) or TBS pH 7.5 buffer (6 μl) for 120 minutes at 20 °C, as positive and negative controls, respectively. After incubation (prior to addition of NEM), a 0.200 ml aliquot of hCD71mab-SO1861- EMCH mixture was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV-vis and alongside positive and negative controls characterised by Ellman’s assay to obtain SO1861-EMCH incorporations. To the bulk hCD71mab- SO1861-EMCH mixture was added an aliquot of freshly prepared NEM solution (2.5 mg/ml, 5 mole equivalents, 2.2 × 10-4 mmol) and the mixtures purified by zeba spin desalting columns eluted with DPBS pH 7.5 to give purified hCD71mab-EMCH-SO1861conjugate. The product was concentrated using vivaspin T4 concentrators (3,000 g, 5 minutes, 5 °C), then normalised to 2.5 mg/ml and filtered to 0.2μm prior to dispensing. Yield: 69 %, SO1861 to hCD71 ratio: 3.8. hCD71mab-SC-SO1861 (Figure 6) hCD71 (55.1 mg, 0.37 μmol, 8.10 mg/ml, 6.80 ml) as supplied was buffered exchanged using a zeba spin desalting column eluting with TBS pH 7.5, and normalised to 3 mg/ml. To hCD71 (50 mg, 0.33 μmol, 5.044 mg/ml) was added an aliquot of freshly prepared TCEP solution (2.00 mg/ml, 3 mole equivalents, 1 μmol), the mixture vortexed briefly then incubated for 210 minutes at 20°C with roller-mixing. After incubation (prior to addition of SO1861-SC-Maleimide), a 1.0 mg (0.201 ml) aliquot of hCD71 solution was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV-vis analysis and Ellman’s assay (2.23 mg/ml, thiol to hCD71 ratio = 4.35). To an aliquot of bulk hCD71-SH (42 mg, 0.28 μmol, 4.978 mg/ml) was added an aliquot of freshly prepared SO1861-SC-Maleimide solution (2.0 mg/ml, 8 mole equivalents, 2.24 μmol, 2.32 ml), the mixture vortexed briefly then incubated for 120 minutes at 20°C. Besides the conjugation reaction, two aliquots of desalted hCD71-SH (0.25 mg, 0.077 ml, 1.67 nmol) were reacted with NEM (8.00 equivalents, 13.4 nmol, 6.7 μl of a 0.25 mg/ml solution) or TBS pH 7.5 buffer (6.7 μl) for 120 minutes at 20°C, as positive and negative controls, respectively. After incubation, a ca. 0.4 mg aliquot of hCD71-SO8161 mixture was removed, purified by gel filtration using zeba spin desalting column into TBS pH 7.5 and characterised by Ellman’s assay alongside positive and negative controls to obtain SO1861 incorporation. To the bulk hCD71- SO1861 mixture was added an aliquot of freshly prepared NEM solution (5 mole equivalents, 1.4 μmol of a 2.5 mg/ml solution) to quench the reaction. The conjugate was purified by zeba 40K MWCO spin desalting columns eluted with DPBS pH 7.5 to give purified hCD71-SO1861 conjugate. An aliquot of the product was analysed by BCA colorimetric assay to ascertain a new EC280 value. Then, the product was normalised to 2.5 mg/ml, filtered to 0.2 μm and then dispensed into aliquots for characterisation, product testing and further conjugation. The result was hCD71-SO1861 conjugate (total yield = 37.8 mg, 89%, SO1861 to hCD71 ratio = 4.2). hCD71mab-dendron(EMCH-SO1861)4 (Figure 7) hCD71 (55.1 mg, 0.37 μmol, 8.10 mg/ml, 6.80 ml) as supplied was buffered exchanged using a zeba spin desalting column eluting with TBS pH 7.5, and normalised to 5 mg/ml. To hCD71 (50 mg, 0.33 μmol, 5.044 mg/ml) was added an aliquot of freshly prepared TCEP solution (2.00 mg/ml, 3 mole equivalents, 1 μmol), the mixture vortexed briefly then incubated for 210 minutes at 20 °C with roller-mixing. After incubation (prior to addition of Dendron-(EMCH-SO1861)4-maleimide1), a 1.0 mg (0.201 ml) aliquot of hCD71 solution was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV-vis analysis and Ellman’s assay (2.23 mg/ml, thiol to hCD71 ratio = 3.8). To an aliquot of bulk hCD71-SH (42 mg, 0.28 μmol, 4.978 mg/ml) was added an aliquot of freshly prepared Dendron-(EMCH-SO1861)4-maleimide1 solution in DMSO (2.0 mg/ml, 8 mole equivalents, 2.24 μmol, 2.32 ml), the mixture vortexed briefly then incubated for 120 minutes at 20 °C. Besides the conjugation reaction, two aliquots of desalted hCD71-SH (0.25 mg, 0.077 ml, 1.67 nmol) were reacted with NEM (8.00 equivalents, 13.4 nmol, 6.7 μl of a 0.25 mg/ml solution) or TBS pH 7.5 buffer (6.7 μl) for 120 minutes at 20 °C, as positive and negative controls, respectively. After incubation, a ca. 0.4 mg aliquot of hCD71- dendron(EMCH-SO8161)4 mixture was removed, purified by gel filtration using zeba spin desalting column into TBS pH 7.5 and characterised by Ellman’s assay alongside positive and negative controls to obtain Dendron-(EMCH-SO1861)4 incorporation. To the bulk hCD71- Dendron-(EMCH- SO1861)4 mixture was added an aliquot of freshly prepared NEM solution (5 mole equivalents, 1.4 μmol of a 2.5 mg/ml solution) to quench the reaction. The conjugate was purified by zeba 40K MWCO spin desalting columns eluted with DPBS pH 7.5 to give purified hCD71-SO1861 conjugate. An aliquot of the product was analysed by BCA colorimetric assay to ascertain a new EC280 value. Then, the product was normalised to 2.5 mg/ml, filtered to 0.2 μm and then dispensed into aliquots for characterisation. The result was hCD71mab-dendron(EMCH-SO1861)4 conjugate (total yield = 22 mg, 37%, dendron-(EMCH-SO1861)4 to hCD71 ratio = 3.2). hCD71mab-dendron(SC-SO1861)8 (Figure 8) hCD71 (55.1 mg, 0.37 μmol, 8.10 mg/ml, 6.80 ml) as supplied was buffered exchanged using a zeba spin desalting column eluting with TBS pH 7.5, and normalised to 3 mg/ml. To hCD71 (50 mg, 0.33 μmol, 5.044 mg/ml) was added an aliquot of freshly prepared TCEP solution (1 mg/ml, 1.3 mole equivalents, 0.43 μmol), the mixture vortexed briefly then incubated for 210 minutes at 20 °C with roller-mixing. After incubation (prior to addition of Dendron-(SC-SO1861)8-maleimide1), a 1.0 mg (0.201 ml) aliquot of hCD71 solution was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV-vis analysis and Ellman’s assay (2.23 mg/ml, thiol to hCD71 ratio = 1.6). To an aliquot of bulk hCD71-SH (42 mg, 0.28 μmol, 4.978 mg/ml) was added an aliquot of freshly prepared Dendron-(SC-SO1861)8-maleimide1 solution in DMSO (2.0 mg/ml, 3.2 mole equivalents, 0.9 μmol, 9 ml), the mixture vortexed briefly then incubated for 120 minutes at 20 °C. Besides the conjugation reaction, two aliquots of desalted hCD71-SH (0.25 mg, 0.077 ml, 1.67 nmol) were reacted with NEM (8.00 equivalents, 13.4 nmol, 6.7 μl of a 0.25 mg/ml solution) or TBS pH 7.5 buffer (6.7 μl) for 120 minutes at 20 °C, as positive and negative controls, respectively. After incubation, a ca.0.4 mg aliquot of hCD71-dendron(SC- SO8161)8 mixture was removed, purified by gel filtration using zeba spin desalting column into TBS pH 7.5 and characterised by Ellman’s assay alongside positive and negative controls to obtain Dendron-(SC-SO1861)8 incorporation. To the bulk hCD71- Dendron-(SC-SO1861)8 mixture was added an aliquot of freshly prepared NEM solution (5 mole equivalents, 1.4 μmol of a 2.5 mg/ml solution) to quench the reaction. The conjugate was purified by zeba 40K MWCO spin desalting columns eluted with DPBS pH 7.5 to give purified hCD71mab-dendron(SC-SO1861)8 conjugate. An aliquot of the product was analysed by BCA colorimetric assay to ascertain a new EC280 value. Then, the product was normalised to 2.5 mg/ml, filtered to 0.2 μm and then dispensed into aliquots for characterisation. The result was hCD71mab-dendron(EMCH-SSO1861)8 conjugate (total yield = 24 mg, 41%, dendron-(SC-SO1861)8 to hCD71 ratio = 1.5 Cetuximab-EMCH-SO1861 To cetuximab (1100 mg) 10 μl/ml each of Tris concentrate (127 mg/ml, 1.05M), Tris.HCl concentrate (623 mg/ml, 3.95 M) and EDTA.2Na.2H2O concentrate (95 mg/ml, 0.26 M) was added to give a 50 mM TBS, 2.5 mM EDTA buffer pH ~7.5. To cetuximab (1087 mg, 4.800 mg/ml, 7.2 × 10-3 mmol) was added an aliquot of freshly prepared TCEP solution (1 mg/ml, 2.72 mole equivalents, 2.0 × 10- 2 mmol, 5.65 mg), the mixture swirled by hand to mix then incubated for 210 minutes at 20°C with roller-mixing. After incubation (prior to addition of SO1861-EMCH), a 2 mg (0.417 ml) aliquot of Ab- SH was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV-vis analysis and Ellman’s assay (3.693 mg/ml, SH to Ab ratio = 4.0). To the bulk Ab-SH was added an aliquot of freshly prepared SO1861-EMCH solution (2 mg/ml, 5.2 mole equivalents, 3.8 × 10-2 mmol, 38.9 ml), the mixtures vortexed briefly then incubated for 120 minutes at 20°C. Besides the conjugation reaction, two aliquots of desalted Ab-SH (0.5 mg, 0.135 ml, 3.33 × 10-6 mmol) were reacted with NEM (8.00 equivalents, 2.66 × 10-5 mmol, 3.3 μg, 13.3 μl of a 0.25 mg/ml solution) or TBS pH 7.5 buffer (13.3 μl) for 120 minutes at 20°C, as positive and negative controls, respectively. After incubation (prior to addition of NEM), a ca.2 mg (0.450 ml) aliquot of Ab – SO1861 mixture was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV-vis (3.271 mg/ml) and alongside positive and negative controls were characterised by Ellman’s assay to obtain SO1861 incorporation. To the bulk Ab – SO1861 mixture was added an aliquot of freshly prepared NEM solution (2.5 mg/ml, 5 mole equivalents, 3.6 × 10-2 mmol, 4.54 mg) and the mixture stored at 2-8°C overnight. The conjugate was purified by 10 × 40 cm Sephadex G50M column eluted with DPBS pH 7.5 to give purified cetuximab – SO1861 conjugate. The aliquot was filtered to 0.2μm and dispensed. The result was a cetuximab – SO1861 conjugate (total yield = 1056 mg, 97%, SO1861 to Ab ratio = 3.9). Cetuximab-dendron(EMCH-SO1861)4, DAR 3.9 To cetuximab (5.95 mg, 1.19 ml) was added 30 μl/ml each of Tris/Tris.HCl/EDTA.concentrate to give a 50mM TBS, 2.5mM EDTA buffer pH ~7.5. To cetuximab (5.85 mg, 4.793 mg/ml, 3.9 × 10-5 mmol) was added an aliquot of freshly prepared TCEP solution (2.72 mole equivalents, 1.1 × 10-4 mmol, 30.4 μg, 30.4 μl of a 1 mg/ml solution), the mixture vortex mixed briefly then incubated for 210 minutes at 20 °C with roller-mixing. After incubation (prior to addition of Dendron-(EMCH- SO1861)4-maleimide1), a 1 mg (0.214 ml) aliquot of Ab-SH was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV- vis analysis and Ellman’s assay (2.3 mg/ml, SH to Ab ratio = 5.9). To the bulk Ab-SH (4.85 mg, 3.2 × 10-5 mmol) was added TBS buffer pH 7.5 (2.3 mL) and an aliquot of freshly prepared Dendron- (EMCH-SO1861)4-maleimide1 solution (8.0 mole equivalents, 2.6 × 10-4 mmol, 2 mg, 1.03 ml of 2 mg/ml solution in DMSO), the mixture vortexed briefly then incubated for 120 minutes at 20°C. Besides the conjugation reaction, two aliquots of desalted Ab-SH (0.25 mg, 0.109 ml, 1.6 × 10-6 mmol) were reacted with NEM (8.00 equivalents, 1.35 × 10-5 mmol, 1.67 μg, 6.7 μl of a 0.25 mg/ml solution) or TBS pH 7.5 buffer (6.7 μl) for 120 minutes at 20 °C, as positive and negative controls, respectively. After incubation (prior to addition of NEM), a ca. 0.1 mg (0.1 ml) aliquot of Ab – Dendron-(EMCH-SO1861)4 mixture was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV-vis and alongside positive and negative controls were characterised by Ellman’s assay to obtain Dendron-(EMCH-SO1861)4 incorporation. To the bulk Ab – Dendron-(EMCH-SO1861)4 mixture was added an aliquot of freshly prepared NEM solution (5 mole equivalents, 1.6 × 10-4 mmol, 0.02 mg, 81 μl of a 0.25 mg/ml solution). The conjugate was purified by 1.6 × 33 cm Sephadex G50M column eluted with DPBS pH 7.5 to give purified cetuximab – Dendron-(EMCH-SO1861)4 conjugate. The product was concentrated then normalised to 2.50 mg/ml using a vivaspin T4 concentrator (3,000 g, 5°C, 30 minutes). The result was a cetuximab – Dendron-(EMCH-SO1861)4 conjugate (total yield = 3.17 mg, 54%, Dendron-(EMCH-SO1861)4 to Ab ratio = 3.9). Cetuximab-dendron(EMCH-SO1861)4, DAR 1.5 To cetuximab (80.0 mg, 16.0 ml) 10 μl/ml each of Tris concentrate (127 mg/ml, 1.05M), Tris.HCl concentrate (623 mg/ml, 3.95M) and EDTA.2Na.2H2O concentrate (95 mg/ml, 0.26M) were added to give a 50mM TBS, 2.5mM EDTA buffer pH ~7.5. To cetuximab (78.1 mg, 4.739 mg/ml, 5.2 × 10- 4 mmol) was added an aliquot of freshly prepared TCEP solution (1.647 mole equivalents, 8.6 × 10- 4 mmol, 245 μg, 245 μl of a 1 mg/ml solution), the mixture vortex mixed briefly then incubated for 90 minutes at 20°C with roller-mixing. After incubation (prior to addition of Dendron-(EMCH- SO1861)4-maleimide1), a 2 mg (0.428 ml) aliquot of Ab-SH was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV- vis analysis and Ellman’s assay (3.774 mg/ml, SH to Ab ratio = 1.9). To the bulk Ab-SH (76.05 mg, 5.1 × 10-4 mmol) was added an aliquot of freshly prepared Dendron-(EMCH-SO1861)4-maleimide1 solution (4.0 mole equivalents, 2.0 × 10-3 mmol, 16.22 mg, 1.62 ml of 10 mg/ml solution in DMSO), the mixture vortexed briefly then incubated for 120 minutes at 20 °C. Besides the conjugation reaction, two aliquots of desalted Ab-SH (0.50 mg, 0.132 ml, 3.3 × 10-6 mmol) were reacted with NEM (4.00 equivalents, 1.3 × 10-5 mmol, 1.67 μg, 6.7 μl of a 0.25 mg/ml solution) or TBS pH 7.5 buffer (6.7 μl) for 120 minutes at 20°C, as positive and negative controls, respectively. After incubation (prior to addition of NEM), a ca. 1 mg (0.235 ml) aliquot of Ab – Dendron-(EMCH- SO1861)4 mixture was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV-vis (2.793 mg/ml) and alongside positive and negative controls were characterised by Ellman’s assay to obtain Dendron-(EMCH-SO1861)4 incorporation. To the bulk Ab – Dendron-(EMCH-SO1861)4 mixture was added an aliquot of freshly prepared NEM solution (5 mole equivalents, 2.5 × 10-3 mmol, 0.32 mg, 1.27 ml of a 0.25 mg/ml solution). The conjugate was purified by 5 × 50 cm Sephadex G50M column eluted with DPBS pH 7.5 to give purified cetuximab – Dendron-(EMCH-SO1861)4 conjugate. The product was concentrated then normalised to 2.50 mg/ml using a vivaspin T4 concentrator (3,000 g, 5°C, 30 minutes). The result was a cetuximab – Dendron-(EMCH-SO1861)4 conjugate (total yield = 68.6 mg, 88%, Dendron-(EMCH-SO1861)4 to Ab ratio = 1.5). Cetuximab-dendron(SC-SO1861)8, DAR 1.5 To cetuximab (10 mg, 5 mg/ml, 2.0 ml) was added 30 μl/ml (60 μl) of a pre-mixed Tris/Tris.HCl/EDTA concentrate comprising Tris concentrate (127 mg/ml, 1.05M), Tris.HCl concentrate (623 mg/ml, 3.95M) and EDTA.2Na.2H2O concentrate (95 mg/ml, 0.26M) combined 1:1:1 v/v, to give a 50mM TBS, 2.5mM EDTA buffer pH ~7.5. This TTE mix was pre-tested against histidine pH 6.0 buffer (30 μl/ml) to yield a final pH 7.53 at 19°C. An aliquot of cetuximab (10 mg, 6.70 × 10-5 mmol, 4.793 mg/ml) was added an aliquot of freshly prepared TCEP solution (1.00 mg/ml, 1.24 mole equivalents, 8.30 × 10-5 mmol, 24 μl), the mixture vortexed briefly then incubated for 210 minutes at 20 °C with roller-mixing. After incubation (prior to addition of Dendron-(SC- SO1861)8-maleimide1), a 1.0 mg (0.212 ml) aliquot of was removed and purified by gel filtration using zeba spin desalting column into TBS pH 7.5. This aliquot was characterised by UV-vis analysis and Ellman’s assay (3.671 mg/ml, SH to Ab ratio = 1.6). To the bulk cet-SH (9.0 mg, 6.00 × 10-5 mmol, 4.739 mg/ml) was added an aliquot of freshly prepared Dendron-(SC-SO1861)8- maleimide1 solution (2.0 mg/ml, 3.2 mole equivalents, 1.92 × 10-4 mmol, 1.845 ml) pre-dispersed in DMSO:TBS pH 7.5 (20:80 v/v), the mixture was vortexed briefly then incubated for 72 hours at 20°C. Besides the conjugation reaction, two aliquots of desalted Cet-SH (0.25 mg, 0.068 ml, 1.67 × 10-6 mmol) were reacted with NEM (3.2 equivalents, 5.34 × 10-6 mmol, 2.7 μl of a 0.25 mg/ml solution) or TBS pH 7.5 buffer (2.7 μl) for 72 hours at 20°C, as positive and negative controls, respectively. After incubation, 50 μl of the cet-Dendron-(SC-SO1861)8 mixture was characterised by Ellman’s assay alongside positive and negative controls to obtain Dendron-(SC-SO1861)8 incorporation. To the bulk cet-Dendron-(SC-SO1861)8 mixture was added an aliquot of freshly prepared NEM solution (5 mole equivalents, 3.00 × 10-4 mmol, 15 μl of a 2.5 mg/ml solution) to quench the reaction. The conjugate was purified by 2.6 × 40 cm Superdex 200 column eluted with DPBS pH 7.5 to give purified cet-Dendron-(SC-SO1861)8 conjugate. The aliquot was concentrated by vivaspin T15 centrifugal filtration (3,000 g, 10 minute intervals, 20°C), analysed by UV-vis spectrophotometry and BCA assay to ascertain a new EC280 and normalised to 2.5 mg/ml, filtered to 0.2 μm and then dispensed into aliquots for in-house characterisation and customer testing. The result was cetuximab-Dendron-(SC-SO1861)8 conjugate (total yield = 4.8 mg, 53%, Dendron-(SC- SO1861)8 to Ab ratio = 1.5). Example 1 Results SO1861-SC-Mal (blocked) (Figure 2B; Molecule (VIII)) was tested for pH dependent release with a release kinetics assay and compared with SO1861-EMCH (blocked) (Figure 3). SO1861-EMCH (blocked) was produced in same way as in Figure 2B. The assay was performed in buffers with pH 7.4, pH 6.0 pH, pH 5.0, or pH 4.0 at 37 ^C for 24 hours. This revealed that SO1861-SC-Mal (blocked) shows a 6-fold faster release compared to SO1861-EMCH (blocked) (50% release at pH 4.0 = 2 hours (SO1861-SC-Mal (Blocked)) vs.50% release in 12 hours (SO1861-EMCH (Blocked)) (Figure 9). Next, SO1861-SC (Figure 2A) and SO1861-SC-Mal (Figure 1; Figure 2B) were tested for endosomal escape enhancing activity. To this end, SO1861, SO1861-EMCH, SO1861-SC and SO1861-SC-Mal were titrated in the presence of a suboptimal, fixed concentration (Figure 21) of 5 pM EGFdianthin (Dia-EGF), 50 pM trastuzumab-saporin, 10 pM CD71-saporin or 10 pM cetuximab- saporin on EGFR/HER2 expressing cells (HeLa and A431, Table 1, 3, 4). This revealed that both SO1861-SC or SO1861-SC-Mal combined with 5 pM EGFdianthin (IC50 = 2000 nM (HeLa); IC50 = 1500 nM (A431)) (Figure 10) or 10 pM Cetuximab-saporin (IC50 = 1500 nM (HeLa); IC50 = 1000 nM (A431) (Figure 11) or 50 pM Trastuzumab-saporin (IC50 = 2000 nM (HeLa); IC50 = 1500 nM (A431)) (Figure 12) was more effective compared to SO1861-EMCH combined with 5 pM EGFdianthin (IC50 = 4000 nM (HeLa); IC50 = 3000 nM (A431)) (Figure 10) or 10 pM cetuximab- saporin (IC50 = 3000 nM (HeLa); IC50 = 2000 nM (A431)) (Figure 11) or 50 pM trastuzumab- saporin (IC50 = 3000 nM (HeLa); IC50 = 2500 nM (A431)) (Figure 12). Unmodified (non-derivatized) SO1861 + 5 pM EGFdianthin or 10 pM cetuximab-saporin or 50 pM trastuzumab-saporin showed strongest cell-killing activity (Figure 10, Figure 11, Figure 12). Next, the ability of SO1861-SC-Mal to induce enhanced cytoplasmic oligonucleotide delivery and targeted gene silencing was tested. To this end, SO1861, SO1861-EMCH or SO1861- SC-Mal were titrated on a fixed, suboptimal concentration (determined in Figure 13A) of 50 nM trastuzumab-S-HSP27BNA, an antisense (BNA) oligonucleotide targeting heat-shock protein 27 (HSP27) conjugated to trastuzumab lysines via a stable linker (S) with a DAR 2, in A431 cells (HER2 +/-) (Table 1, Figure 13B). Next, HSP27 mRNA gene silencing activity in treated cells was determined. This revealed that SO1861-SC-Mal + 50 nM trastuzumab-HSP27BNA (IC50 of 600 nM) (Figure 13 B) is more effective in gene silencing activity compared to SO1861-EMCH + 50 nM trastuzumab-HSP27BNA (IC50 of 2000 nM) in A431 cells (Figure 13B). Next, cell toxicity was determined. To this end, SO1861, SO1861-EMCH SO1861-SC and SO1861-SC-Mal were titrated on HeLa and A431 cells (Figure 14, Table 3, Table 4). This revealed that unmodified SO1861 showed toxicity at IC50 = 9000 nM (HeLa) and IC50 = 2000 nM (A431), whereas in HeLa cells SO1861-EMCH or SO1861-SC-Mal showed toxicity at IC50 > 100000 nM. In A431 cells, SO1861-EMCH showed toxicity at IC50 > 30000 nM, whereas SO1861-SC-Mal and SO1861-SC showed toxicity at IC50 = 6000 nM (Figure 14; Table 3, Table 4). Table 3. IC50 overview of modified SO1861 activity (HeLa cells)/toxicity (HeLa cells)/hemolysis (red blood cells)/CMC.
Figure imgf000187_0001
Next, a haemolysis assay was performed; for this SO1861, SO1861-EMCH, SO1861-EMCH (blocked) SO1861-SC, SO1861-SC-Mal and SO1861-SC-Mal (blocked) were tested on fresh human red blood cells (RBC). This revealed haemolytic activity of SO1861-SC at IC50 = 100000 nM, SO1861-SC-Mal at IC50 = 250000 nM and SO1861-SC-Mal (blocked) at IC50 = 100000 nM (Figure 15; Table 3, Table 4), whereas no haemolytic activity was detected with SO1861-EMCH at the range of concentrations tested (IC50 > 500000 nM) and SO1861-EMCH (blocked) showed haemolytic activity at IC50 = 6000 nM (Figure 15; Table 3, Table 4). Next, the critical micelle concentration (CMC) was determined for SO1861, SO1861-EMCH, SO1861-EMCH (blocked), SO1861-SC-Mal and SO1861-SC-Mal (blocked) (Table 3, Table 4). This revealed a CMC value of 129 µM for SO1861, whereas for SO1861-SC-Mal and SO1861-EMCH, a CMC could not be detected and determined within this range of concentrations, which indicates that the CMS for these two saponin derivatives is higher than 800 ^M (Table 3, Table 4). Table 4. IC50 overview of modified SO1861 activity (A431 cells)/toxicity (A431 cells)/haemolysis (red blood cells)/CMC.
Figure imgf000188_0001
Next, SO1861-semicarbazone-Mal (SO1861-SC-Mal) was conjugated via cysteine residues (Cys) to cetuximab (a monoclonal antibody binding human EGFR), with a DAR 4, to yield cetuximab-(SC- SO1861)4 as depicted in Figure 6. Cetuximab-(SC-SO1861)4 was titrated on a fixed, suboptimal concentration (see Figure 21) of 10 pM CD71mab-saporin (monoclonal antibody binding human CD71; clone OKT-9, conjugated to the protein toxin saporin). Targeted protein toxin mediated cell killing was then determined on EGFR/CD71 expressing cells (Table 1; A431, EGFR++/CD71+; CaSki, EGFR++/CD71+). This revealed strong cell killing at low concentrations of cetuximab-(SC- SO1861)4 (A431: IC50 = 0,6 nM and CaSki IC50 = 1 nM; Figure 16A, 16B). Compared to cetuximab- (EMCH-SO1861)4 , activity was enhanced (A431: IC50 = 2 nM and CaSki IC50 = 30 nM; Figure 16A, 16B). Equivalent concentrations of cetuximab-(SC-SO1861)4 or cetuximab-(EMCH-SO1861)4 could not induce any cell killing activity in EGFR++/CD71+ expressing cells. This shows that compared to cetuximab-(EMCH-SO1861)4, cetuximab-(SC-SO1861)4 more potently enhances endosomal escape of the CD71mab conjugated protein toxin (the same concentration of 10 pM the protein toxin is not effective in the absence of saponin; see Figure 21), thereby inducing efficient cell killing of EGFR++/CD71+ expressing cells. Improved acid-sensitive linker release of SO1861 from an antibody at low pH in endosomes thus improves the efficacy of delivery of a protein toxin such as a ribosomal inactivating protein toxin to the cytoplasm by mAb-SO1861 conjugates. Next, cetuximab-(SC-SO1861)4 was titrated alongside a fixed concentration of 10 pM CD71mab-saporin, and targeted protein toxin-mediated cell killing was determined on HeLa (Table 1;EGFR+/-/CD71+) and A2058 (Table1, EGFR-/CD71+) cells. Cetuximab-(SC-SO1861)4 + 10 pM CD71mab-saporin in HeLa cells (EGFR+/-/HER2+/-) could already induce partial protein toxin- mediated cell killing at lower concentrations (between 50-100 nM) of cetuximab-(SC-SO1861)4 (compared to HeLa: IC50 = 500 nM, Figure 17A), whereas this was not observed for cetuximab- (EMCH-SO1861)4 + 10 pM CD71mab-saporin (HeLa: IC50 = 1000 nM) (Figure 17 A). In A2058 cells lacking EGFR expression, no improved activity was observed for cetuximab-(SC-SO1861)4 + 10 pM CD71mab-saporin (A2058: IC50 = 1000 nM); Figure 17B). This shows that improved release of SO1861 in acidified endosomes from semicarbazone linker also enables cytoplasmic payload delivery in cells with lower EGFR expression than is feasible with less efficient releasing linkers such as EMCH.. However, when EGFR expression is absent (such as in A2058 cells), SO1861 concentrations required to induce endosomal escape and cytoplasmic delivery of the protein toxin are not reached (i.e., below threshold), demonstrating enhanced delivery efficiency does not increase delivery to untargeted cells and therefore maintain target selectivity. Next, SO1861-SC-Mal was conjugated via cysteine residues (Cys) to trastuzumab (monoclonal antibody binding human HER2), with a DAR 4, to yield trastuzumab-(SC-SO1861)4. Trastuzumab-(SC-SO1861)4 was titrated in combination with a fixed concentration of 10 pM CD71mab-saporin, and targeted protein toxin mediated cell killing was determined on HER2/CD71 expressing cells (Table 1; SK-BR-3: HER2++/CD71+) (Figure 18). This revealed strong cell killing at low concentrations of trastuzumab-(SC-SO1861)4 (SK-BR-3: IC50 = 0,3 nM; Figure 18). Compared to trastuzumab-(EMCH-SO1861)4, the activity was 5-fold improved (SK-BR-3: IC50 = 1 nM; Figure 18). Equivalent concentrations of cetuximab-(SC-SO1861)4 or cetuximab-(EMCH-SO1861)4 alone could not induce any significant cell killing activity in SK-BR-3 cells (Figure 18). This shows that compared to trastuzumab-(EMCH-SO1861)4, trastuzumab-(SC-SO1861)4 more potently enhances endosomal escape of the CD71mab conjugated protein toxin (at otherwise non-effective concentrations; Figure 21), thereby inducing efficient cell killing of HER2++/CD71+ expressing cells. Improved release of SO1861 from an antibody by the low pH in endosomes thus improves the effectiveness of mAb-SO1861 conjugates for delivery of a ribosomal inactivating protein toxin to the cytoplasm. Next, trastuzumab-(SC-SO1861)4 was titrated along a fixed concentration of 10 pM CD71mab-saporin on JIMT-1 (Table1; HER2+/-/CD71+) and MDA-MB-468 (Table 1; HER2-/CD71+). Next, targeted protein toxin-mediated cell killing was determined. Trastuzumab-(SC-SO1861)4 + 10 pM CD71mab-saporin in JIMT-1 cells (HER2+/-/CD71+) could already induce toxin mediated cell killing at low conjugated SO1861 concentrations (JIMT-1: IC50 = 100 nM; Figure 19A) whereas this was not observed for trastuzumab-(EMCH-SO1861)4 + 10 pM CD71mab-saporin (JIMT-1: IC50 = 1000 nM; Figure 19A). In MDA-MB-468 cells (that lack HER2 receptor expression), no improved activity was observed for trastuzumab-(SC-SO1861)4 + 10 pM CD71mab-saporin (MDA-MB-468: IC50 = 1000 nM; Figure 19B). This shows that improved release of SO1861 in acidified endosomes from semicarbazone-conjugated SO1861 also enables enhanced cytoplasmic delivery in cells with lower HER2 expression than can be targeted using EMCH based linkers. When HER2 expression is absent (in MDA-MB-468 cells), effective SO1861 concentrations are not reached (i.e., below threshold) to induce endosomal escape and cytoplasmic delivery of the protein toxin), demonstrating enhanced delivery efficiency linkers do not increase delivery to untargeted cells and therefore maintain target selectivity. Next, cetuximab-(SC-SO1861)4 was titrated along a fixed concentration of 50 pM Trastuzumab-HSP27BNA on A431 cells (EGFR++/HER2+/-). HSP27 gene silencing was then determined. This revealed strong HSP27 gene silencing at low concentrations of cetuximab-(SC- SO1861)4 (A431: IC50 = 0,5 nM; Figure 20), comparable to the activity observed with cetuximab- (EMCH-SO1861)4 + 50 pM trastuzumab-HSP27BNA (A431: IC50 = 0,5 nM Figure 20). In vitro potency of Cetuximab-(SC-SO1861)-HSP27 BNA (DAR 4/DAR2) Gene silencing potency of cetuximab-(SC-SO1861)-(HSP27BNA) (DAR4 for the SO1861 moieties/DAR2 for the HSP27 BNA molecule) and cetuximab-(EMCH-SO1861)-(HSP27BNA) (DAR4 for SO1861/DAR2 for the BNA) were compared on A431 cells (Table 1; EGFR++). This revealed that cetuximab-(SC-SO1861)-(HSP27BNA) (DAR4/DAR2) showed improved potency (IC50 = 0,5 nM) compared to cetuximab-(EMCH-SO1861)-(HSP27BNA) (DAR4/DAR2) (IC50 = 1 nM), indicating that SO1861 release from the antibody in the endosome enhances the potency of the Cetuximab-(SC-SO1861)-(HSP27BNA) conjugate (DAR4/DAR2) over that of the corresponding EMCH-SO1861 based conjugate (Figure 22). In vitro potency of CD71mab-(SC-SO1861) SO1861-SC-Mal or Dendron-(SC-SO1861)8-Mal was conjugated via cysteine residues (Cys) to CD71mab (a monoclonal antibody binding human CD71) to yield CD71mab-(SC-SO1861) (DAR4.2) or CD71mab-dendron(SC-SO1861)8 (DAR 1.5). CD71mab-(SC-SO1861) (DAR4.2) or CD71mab-dendron(SC-SO1861)8 (DAR 1.5, on average 12 SO1861 molecules, as depicted in Figure 8A, 8B) or CD71mab-(EMCH-SO1861) (DAR3.8) or CD71mab-dendron(EMCH-SO1861)4 (DAR 3.2, on average 12 SO1861 molecules; as depicted in Figure 7A, 7B) was titrated in combination with a fixed suboptimal concentration (see Figure 21) of 5 pM DianthinEGF (Dia-EGF; dianthin protein toxin fused to EGF). Targeted protein toxin mediated cell killing potency was determined on CD71+/EGFR+ expressing cells (Table 1; SK-BR-3 (CD71+/EGFR+), JIMT-1 (CD71+/EGFR+), HeLa (CD71+/EGFR+), MDA-MB-468 (CD71+/EGFR+), A431 (CD71+/EGFR+) as well as on A2058 (CD71+/EGFR-) (Figure 23). This revealed strong cell killing at low concentrations of SO1861 when treated with CD71mab-SC-SO1861 (DAR4.2) or CD71mab-dendron(SC- SO1861)8 (DAR 1.5) (SK-BR-3: IC50 = 1 nM; JIMT-1 IC50 = 10 nM; HeLa IC50 = 10 nM MDA-MB- 468 IC50 = 10 nM; A431 IC50 = 100 nM (Figure 23A-23E), whereas treatment with CD71mab- (EMCH-SO1861) (DAR3.8) or CD71mab-dendron(EMCH-SO1861)4 (DAR3.2) was less potent (SK-BR-3: IC50 = 10-20 nM; JIMT-1 IC50 = 1000 nM; HeLa IC50 = 1000 nM; MDA-MB-468 IC50 = 600 nM; A431 IC50 = 900 nM (Figure 23A-23E). A2058 cells, lacking EGFR expression (Table 1) were not responsive to any of the treatments; only at very high concentrations, some cell-killing activity was observed (Figure 23F). This shows that compared to CD71mab-(EMCH-SO1861), CD71mab-(SC-SO1861) is more potent, by further improving enhancing endosomal escape of the 5 pM of EGFdianthin toxin and inducing efficient cell killing only in CD71+/EGFR+ expressing cells. Improved release of SO1861 from from SC-linked CD71 receptor targeted monoclonal antibody in the endosome thus improves the delivery of a protein toxin such as a ribosomal inactivating protein toxin to the cytoplasm as compared to EMCH-linked CD71 conjugates. EXAMPLE 2 The inventors have previously established that numerous aberrant or diseased cells such as tumor cells can be targeted with a conjugate comprising a ligand such as EGF or an antibody and comprising a saponin such as a saponin as listed in Table A1, without wishing to be bound by any theory, resulting in the endocytosis of the conjugate and the accumulation of the saponin in the endosome of the targeted cell, facilitating the endosomal escape of a molecule such as an oligonucleotide or a proteinaceous toxin, which is present in said same cell in the same endosomes at the same time, from the endosome and into the cytosol of the targeted cell. On the target cell, typically an endocytic receptor was targeted, such as EGFR, HER2 and CD71. CD71 is preferred. Typically, the conjugates comprised a monoclonal antibody capable of binding to such an endocytic cell-surface receptor on the target cell, or comprised at least one sdAb binding such a receptor. Examples of suitable endocytic receptor targeting ligands and antibodies were EGF, VHH capable of binding to HER2, VHH capable of binding to CD71, VHH capable of binding to EGFR, MoAb capable of binding to CD71, MoAb capable of binding to HER2 such as trastuzumab and pertuzumab, MoAb capable of binding to EGFR such as cetuximab and matuzumab. Typically, the saponin comprised by the conjugate was any one of SO1861, SA1641, GE1741, QS- 21, QS-21A, QS21-B, Quil-A, SO1832, SO1904, and SO1862. The inventors have previously successfully established that oligonucleotides such as BNA HSP27 and proteinaceous toxins such as saporin and dianthin are efficiently endocytosed and released from endosomes into the cell cytosol under influence of a conjugate comprising a saponin according to Table A1. In the saponin-comprising conjugates, the saponin moieties were for example linked to an antibody involving a hydrazone bond formed at the C-23 position, i.e. involving the aldehyde group at position C-23 of the saponin. Under influence of the acidic pH in the endosomes of targeted cells, the hydrazone bond was cleaved and the aldehyde group at position C-23 was again formed, endowing the saponin with the desired endosomal escape enhancing activity towards an effector molecule present in the same endosome, without wishing to be bound by any theory. The inventors previously established the beneficial effects of endocytosing a saponin-bearing conjugate, when cytosolic delivery of a selected effector molecule such as an oligonucleotide in said target cell is desired. Such saponin-bearing conjugate was for example co-administered with a second conjugate such as an ADC or an AOC. This is referred to as the 2-component approach. Alternatively, the saponin was covalently bound (e.g., via the hydrazone bond) to such an ADC or AOC, which also resulted in enhanced activity of the effector molecule comprised by the ADC or AOC, once present inside the target cell. This is referred to as the 1-component approach. Illustrative examples of such 2-component combinations are for example published in international applications WO2020126627, WO2021261995, and WO2021259925. Illustrative examples of such 1-component conjugates are for example published in international application WO2020126620. In Table T1, references to a series of representative examples in these listed international applications are provided. These examples show that for example CD71 is a suitable target for delivery of saponin and/or effector moiety into a target cell such as an aberrant or diseased cell. These examples also show that for example an oligonucleotide is a suitable effector molecule to be delivered in a target cell and into the cytosol of said cell, under influence of a saponin-bearing conjugate.
TABLE T1: published examples of a conjugate comprising a saponin and a cell-targeting ligand, wherein the saponin is not linked with the ligand via a semicarbazone bond, said conjugate combined with a second conjugate comprising a cell-targeting ligand and an effector moiety, and published examples of 1-component conjugates comprising a cell-targeting ligand, an effector moiety and a saponin, wherein the saponin is not linked via a semicarbazone bond in the 1- component conjugate.
Figure imgf000193_0001
Figure imgf000194_0001
TFA trifluoroacetic acid TFL trifunctional linker Analytical methods LC-MS method 1 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, mass ranges depending on the molecular weight of the product: neg or neg/pos within in a range of 1500-2400 or 2000-3000; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Acquity C18, 50×2.1 mm, 1.7 μm Temp: 60ºC, Flow: 0.6 mL/min, lin. Gradient depending on the polarity of the product: At0 = 2% A, t5.0min = 50% A, t6.0min = 98% A Bt0 = 2% A, t5.0min = 98% A, t6.0min = 98% A Posttime: 1.0 min, Eluent A: acetonitrile, Eluent B: 10 mM ammonium bicarbonate in water (pH=9.5). LC-MS method 2 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, mass ranges depending on the molecular weight of the product: pos/neg 100-800 or neg 2000-3000; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Waters XSelectTM CSH C18, 50×2.1 mm, 2.5 μm, Temp: 25°C, Flow: 0.5 mL/min, Gradient: t0min = 5% A, t2.0min = 98% A, t2.7min = 98% A, Posttime: 0.3 min, Eluent A: acetonitrile, Eluent B: 10 mM ammonium bicarbonate in water (pH = 9.5). LC-MS method 3 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, mass ranges depending on the molecular weight of the product pos/neg 105-800, 500-1200 or 1500-2500; ELSD: gas pressure 40 psi, drift tube temp: 50°C; column: Waters XSelectTM CSH C18, 50×2.1 mm, 2.5 μm, Temp: 40°C, Flow: 0.5 mL/min, Gradient: t0min = 5% A, t2.0min = 98% A, t2.7min = 98% A, Posttime: 0.3 min, Eluent A: 0.1% formic acid in acetonitrile, Eluent B: 0.1% formic acid in water. LC-MS method 4 Apparatus: Waters IClass; Bin. Pump: UPIBSM, SM: UPISMFTN with SO; UPCMA, PDA: UPPDATC, 210-320 nm, SQD: ACQ-SQD2 ESI, mass ranges depending on the molecular weight of the product: pos/neg 100-800 or neg 2000-3000; ELSD: gas pressure 40 psi, drift tube temp: 50°C column: Waters Acquity Shield RP18, 50×2.1 mm, 1.7 μm, Temp: 25ºC, Flow: 0.5 mL/min, Gradient: t0min = 5% A, t2.0min = 98% A, t2.7min = 98% A, Posttime: 0.3 min, Eluent A: acetonitrile, Eluent B: 10 mM ammonium bicarbonate in water (pH=9.5). Preparative methods Preparative MP-LC method 1 Instrument type: Reveleris™ prep MPLC; column: Waters XSelectTM CSH C18 (145×25 mm, 10 μm); Flow: 40 mL/min; Column temp: room temperature; Eluent A: 10 mM ammonium bicarbonate in water pH = 9.0); Eluent B: 99% acetonitrile + 1% 10 mM ammonium bicarbonate in water; Gradient: At0min = 5% B, t1min = 5% B, t2min = 10% B, t17min = 50% B, t18min = 100% B, t23min = 100% B At0min = 5% B, t1min = 5% B, t2min = 20% B, t17min = 60% B, t18min = 100% B, t23min = 100% B ; Detection UV: 210, 235, 254 nm and ELSD. Preparative MP-LC method 2 Instrument type: Reveleris™ prep MPLC; Column: Phenomenex LUNA C18(3) (150×25 mm, 10 μm); Flow: 40 mL/min; Column temp: room temperature; Eluent A: 0.1% (v/v) Formic acid in water, Eluent B: 0.1% (v/v) Formic acid in acetonitrile; Gradient: At0min = 5% B, t1min = 5% B, t2min = 20% B, t17min = 60% B, t18min = 100% B, t23min = 100% B Bt0min = 2% B, t1min = 2% B, t2min = 2% B, t17min = 30% B, t18min = 100% B, t23min = 100% B Ct0min = 5% B, t1min = 5% B, t2min = 10% B, t17min = 50% B, t18min = 100% B, t23min = 100% B Dt0min = 5% B, t1min = 5% B, t2min = 5% B, t17min = 40% B, t18min = 100% B, t23min = 100% B ; Detection UV : 210, 235, 254 nm and ELSD. Preparative LC-MS method 3 MS instrument type: Agilent Technologies G6130B Quadrupole; HPLC instrument type: Agilent Technologies 1290 preparative LC; Column: Waters XSelectTM CSH (C18, 150×19 mm, 10 µm); Flow: 25 ml/min; Column temp: room temperature; Eluent A: 100% acetonitrile; Eluent B: 10 mM ammonium bicarbonate in water pH = 9.0; Gradient: At0 = 20% A, t2.5min = 20% A, t11min = 60% A, t13min = 100% A, t17min = 100% A Bt0 = 5% A, t2.5min = 5% A, t11min = 40% A, t13min = 100% A, t17min = 100% A ; Detection: DAD (210 nm); Detection: MSD (ESI pos/neg) mass range: 100 – 800; Fraction collection based on DAD. Preparative LC-MS method 4 MS instrument type: Agilent Technologies G6130B Quadrupole; HPLC instrument type: Agilent Technologies 1290 preparative LC; Column: Waters XBridge Protein (C4, 150×19 mm, 10µm); Flow: 25 ml/min; Column temp: room temperature; Eluent A: 100% acetonitrile; Eluent B: 10 mM ammonium bicarbonate in water pH = 9.0; Gradient: At0 = 2% A, t2.5min = 2% A, t11min = 30% A, t13min = 100% A, t17min = 100% A Bt0 = 10% A, t2.5min = 10% A, t11min = 50% A, t13min = 100% A, t17min = 100% A Ct0 = 5% A, t2.5min = 5% A, t11min = 40% A, t13min = 100% A, t17min = 100% A ; Detection: DAD (210 nm); Detection: MSD (ESI pos/neg) mass range: 100 – 800; Fraction collection based on DAD Flash chromatography Grace Reveleris X2® C-815 Flash; Solvent delivery system: 3-piston pump with auto-priming, 4 independent channels with up to 4 solvents in a single run, auto-switches lines when solvent depletes; maximum pump flow rate 250 mL/min; maximum pressure 50 bar (725 psi); Detection: UV 200-400 nm, combination of up to 4 UV signals and scan of entire UV range, ELSD; Column sizes: 4-330g on instrument, luer type, 750g up to 3000g with optional holder. UV-vis spectrophotometry Protein concentrations were determined using a Thermo Nanodrop 2000 spectrophotometer and the following mass based extinction coefficient ε280 values ((mg/ml)-1 cm-1); Oligo concentrations were determined using a molar extinction coefficient ε260 value of 153,000 M-1 cm-1. Ellman’s assay was carried out using a Perkin Elmer Lambda 25 Spectrophotometer and a literature molar extinction coefficient ε412 value of 14150 M-1 cm-1 for TNB. Experimentally determined molar extinction coefficient ε495 = 58,700 M-1 cm-1 and Rz280:495 = 0.428 were used for SAMSA- fluorescein SEC The conjugates were analysed by SEC using an Akta Purifier 10 system and Biosep SEC-s3000 column eluted with DPBS:IPA (85:15). Conjugate purity was determined by integration of the conjugate UV peak area versus UV peak area of impurities/aggregate forms. SDS-PAGE and Western Blotting Native proteins and conjugates were analysed under heat denaturing non-reducing and reducing conditions by SDS-PAGE against a protein ladder using a 4-12% bis-tris gel and MES as running buffer (200V, ~40 minutes). Samples were prepared to 0.5 mg/ml, comprising LDS sample buffer and MOPS running buffer as diluent. For reducing samples, DTT was added to a final concentration of 50 mM. Samples were heat treated for 2 minutes at 90-95°C and 5 μg (10 μl) added to each well. Protein ladder (10 μl) was loaded without pre-treatment. Empty lines were filled with 1× LDS sample buffer (10 μl). After the gel was run, it was washed thrice with DI water (100 ml) with shaking (15 minutes, 200 rpm). Coomassie staining was performed by shaker-incubating the gel with PAGEBlue protein stain (30 ml) (60 minutes, 200 rpm). Excess staining solution was removed, gels were rinsed twice with DI water (100 ml) and destained with DI water (100 ml) (60 minutes, 200 rpm). The resulting gel was imaged and then further processed using ImageJ (Rasband, W.S., ImageJ, U. S. National Institutes of Health, Bethesda, Maryland, USA). TBEU-PAGE Native protein, conjugates and BNA standard were analysed under heat denaturing non-reducing and reducing conditions by TBEU-PAGE against an oligo ladder using a 15% TBE-Urea gel and TBE as running buffer (180V, ~60 minutes). Samples were prepared to 0.5 mg/ml, and BNA standard was prepared to 20 μg/ml, respectively, all comprising TBE Urea sample buffer and purified H2O as diluent. Samples and standards were heat treated for 3 minutes at 70°C and 10 μl, equating to 5 μg of protein and conjugate samples, and 0.2 μg of BNA, were added per lane. Oligo ladder reconstituted to 0.1 μg/band/ml in TE pH 7.5 (2 μl) was loaded without pre-treatment. After the gel was run, it was stained with freshly prepared ethidium bromide solution (1 μg/ml) with shaking (40 minutes, 200 rpm). The resulting gel was visualised by UV epi-illumination (254 nm), imaged and then further processed using ImageJ. MALDI-TOF-MS MALDI-TOF spectra were recorded on a MALDI-Mass Spectrometer (Bruker Ultrafex III). Typically, the sample dissolved in MilliQ water in nanomolar to micromolar range was spotted on the target (MTP 384 target plate polished steel T F, Bruker Daltons) using either super-DHB (99%, Fluka) or sinapinic acid (SA, 99%, Sigma-Aldrich) as the matrix dissolved in acetonitrile (MADLI-TOF-MS tested, Sigma) / 0.1 % TFA (7:3 v/v) via the dried-droplet-method. PepMix (Peptide Calibration Standard, Bruker Daltons) or ProteMass (Protein Calibration Standard, Sigma-Aldrich) served as calibration standards. Trifunctional linker-(L-hydrazone-SO1861)- (L-BNA oligo) – (Trivalent-GalNAc) synthesis (Figure 36) The trifunctional linker (TFL) has the IUPAC name: 5,8,11,18,21,24,27-Heptaoxa-2,14,30- triazatritriacontanoic acid, 14-[16-(11,12-didehydrodibenz[b,f]azocin-5(6H)-yl)-13,16-dioxo-3,6,9- trioxa-12-azahexadec-1-yl]-33-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)-15,31-dioxo-, (1R,4E)-4- cycloocten-1-yl ester. The trifunctional linker has the following formula (XXI):
Figure imgf000199_0001
Intermediate 1: SO1861-L-hydrazone-azide (molecule 3) To SO1861 (60 mg, 0.032 mmol, molecule 1) and 1-azido-3,6,9,12-tetraoxapentadecane-15- hydrazide (39.3 mg, 0.129 mmol, molecule 2) was added methanol (extra dry, 1.00 mL) and TFA (9.86 µl, 0.129 mmol). The reaction mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative MP- LC.1 Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (58.4 mg, 84%) as a white fluffy solid. Purity based on LC-MS 99%. LRMS (m/z): 2150 [M-H]1- LC-MS r.t. (min): 1.103B Intermediate 2: Trifunctional linker-(L-hydrazone-SO1861)-(TCO)-(Maleimide) (molecule 5) A solution of TFL-(DBCO)-(TCO)-(Maleimide) (15 mg, 12.5 µmol, molecule 4) in DMF (2.0 mL) was added to SO1861-L-hydrazone-azide (26.8 mg, 12.5 µmol, molecule 3). The reaction mixture was shaken for 30 min and left standing at room temperature. After 30 min, the reaction mixture was submitted to preparative MP-LC.1C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (31.4 mg, 75%) as a white fluffy solid. Purity based on LC-MS 96%. MS (m/z): 3354 [M-H]1- Intermediate 3: Trivalent GalNAc-thioacetate (molecule 8) Trivalent GalNAc-amine formate (18.7 mg, 11.0 µmol, molecule 6; Figure 36B) and 4-nitrophenyl 3-(acetylthio)propanoate (5.90 mg, 21.9 µmol, molecule 7) were dissolved in a solution of NMM (2.41 µL, 21.9 µmol) in DMF (0.50 mL). The trivalent GalNAc-amine formate is obtained based on the trivalent GalNAc-azide which is the Intermediate 7 as shown in Fig.35D. In Figure 36B, the formate of molecule 6 is not shown for simplicity. The reaction mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was evaporated in vacuo and the residue was dissolved in a mixture of 0.1% formic acid in water and 0.1% formic acid in acetonitrile (9:1, v/v, 1 mL). The resulting solution was directly subjected to preparative MP- LC.2B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (13.0 mg, 66%) as a white solid. Purity based on LC-MS 100%. LRMS (m/z): 1749 [M-43]1-, 1792 [M-H]1 LC-MS r.t. (min): 1.241B Intermediate 4: Trifunctional linker-(L-SO1861)-(TCO)-(trivalent GalNAc) (molecule 9) Trivalent GalNAc-thioacetate (13.0 mg, 7.25 µmol, molecule 8) was dissolved in methanol (0.50 mL). Next, a 1 M solution of sodium hydroxide (7.98 µL, 7.98 µmol) was added. The reaction mixture was shaken for 1 min and left standing at room temperature. After 30 min, the reaction mixture was added to a freshly prepared solution of TFL-(DBCO)-(TCO)-(Maleimide) (20.6 mg, 6.13 µmol, molecule 5) in 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 2.00 mL).The resulting mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative MP-LC.2A Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (3.83 mg, 21%) as a white solid. Purity based on LC-MS 89%. MS (m/z): 5106 [M + H]+ Intermediate 5: methyltetrazine-L-ApoB BNA oligo (molecule 12) To ApoB BNA oligo disulfide (3.3 mg, 0.686 µmol, molecule 10) was added a solution of 20 mM ammonium bicarbonate with 2.5 mM TCEP (1.00 mL, 2.5 µmol). The reaction mixture was shaken for 1 min and left standing at room temperature. After 1 hour, the reaction mixture was filtered by using a centrifugal filter with a molecular weight cut-off of 3000 Da (5000 × g for 30 min, 2 × 0.50 mL). Next, the residue solution was washed twice with a solution of 20 mM ammonium bicarbonate with 2.5 mM TCEP (0.50 mL), each time filtered under the same conditions described above. Next, the residue solution was diluted with 20 mM ammonium bicarbonate (1.50 mL) and the resulting mixture was directly added to a solution of (E)-1-(4-((2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)hexanoyl)hydrazineylidene)methyl)benzamido)-N-(4-(6-methyl-1,2,4,5-tetrazin-3-yl)benzyl)- 3,6,9,12-tetraoxapentadecan-15-amide (1.36 mg, 1.73 µmol, molecule 11) in acetonitrile (0.5 mL). The reaction mixture was shaken for 1 min and left standing at room temperature. After 30 min, the reaction mixture was frozen and lyophilized overnight to yield the crude title product as a pink fluffy solid. To the crude product was added a solution of 20 mM ammonium bicarbonate (1.50 mL) and the resulting suspension was filtered over a 0.45 µm syringe filter. The filtrate was lyophilized overnight to yield the title product (3.4 mg, 89%) as a pink fluffy solid. Purity based on LC-MS 90%. MS (m/z): 5579 [M+Na]+ Trifunctional linker-(L-hydrazone-SO1861)-(L-BNA oligo)-(trivalent GalNAc) (molecule 13) TFL-(L-hydrazone-SO1861)-(TCO)-(trivalent GalNAc) (16.1 mg, 3.15 µmol, molecule 9) and Methyltetrazine-BNA oligo (10.2 mg, 1.83 µmol, molecule 12) were dissolved in a solution of 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 1.00 mL). The reaction mixture was shaken for 1 min and left standing at room temperature. After 3 hours, the reaction mixture was frozen and lyophilized overnight. The crude product was dissolved in 20 mM ammonium bicarbonate (1 mL) and the resulting solution was directly subjected to preparative LC-MS.1B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (27.2 mg, 81%) as a white fluffy solid. Purity based on LC-MS 91%. MS (m/z): 10660 [M + H] + Using a similar approach as for synthesis of Trifunctional linker-(L-hydrazone-SO1861)-(L-BNA oligo)-(trivalent GalNAc) (molecule 13), a conjugate in which the ApoB BNA was replaced for a BNA with a scrambled ApoB nucleic acid sequence (molecule 12 a) was synthesized (molecule 13a). Trifunctional linker-(dendron(-L-hydrazone-SO1861)4)- (L-BNA oligo) – (Trivalent-GalNAc) synthesis (Figure 37) Intermediate 6: SO1861-EMCH (molecule 15) To SO1861 (121 mg, 0.065 mmol, molecule 1) and EMCH.TFA (110 mg, 0.325 mmol, molecule 14) was added methanol (extra dry, 3.00 mL) and TFA (0.020 mL, 0.260 mmol). The reaction mixture was stirred at room temperature. After 1.5 hours, the reaction mixture was subjected to preparative MP-LC.1 Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (120 mg, 90%) as a white fluffy solid. Purity based on LC-MS 96%. LRMS (m/z): 2069 [M-1]1- LC-MS r.t. (min): 1.084 Intermediate 7: dendron(-L-SO1861)4-amine (molecule 17) N,N'-((9S,19S)-14-(6-aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo- 4,11,14,17-tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide) formate (2.73 mg, 3.13 µmol, molecule 16) was dissolved in a mixture of 20 mM NH4HCO3 with 0.5 mM TCEP/acetonitrile (3:1, v/v, 3.00 mL). Next, SO1861-EMCH (29.2 mg, 0.014 mmol, molecule 15) was added and the reaction mixture was stirred at room temperature. After 1.5 hours, the reaction mixture was subjected to preparative LC-MS.3B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (12.3 mg, 43%) as a white fluffy solid. Purity based on LC-MS 97%. LRMS (m/z): 1517 [M-6]6-, 1821 [M-5]5-, 2276 [M-4]4- LC-MS r.t. (min): 4.395A Intermediate 8: dendron(-L-SO1861)4-azide (molecule 19) Dendron(SO1861)4-amine (6.81 mg, 0.748 µmol, molecule 17) and 2,5-dioxopyrrolidin-1-yl 1-azido- 3,6,9,12-tetraoxapentadecan-15-oate (2.90 mg, 7.48 µmol, molecule 18) were dissolved in DMF(1.00 mL). Next, DIPEA (1.302 µL, 7.48 µmol) was added, the mixture was shaken for 1 min and then left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (5.86 mg, 84%) as a white fluffy solid. Purity based on LC-MS 90%. LRMS (m/z): 2344 [M-4]4- LC-MS r.t. (min): 4.785B Intermediate 9: Trifunctional linker (DBCO)-(TCO)-(trivalent GalNAc) (molecule 20) Trivalent GalNAc-thioacetate (13.0 mg, 7.25 µmol, molecule 8) was dissolved in methanol (0.50 mL). Next, a 1 M solution of sodium hydroxide (7.98 µL, 7.98 µmol) was added. The reaction mixture was shaken for 1 min and left standing at room temperature. After 30 min, the reaction mixture was added to a freshly prepared solution of trifunctional linker (7.39 mg, 6.13 µmol, molecule 4) in 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 2.00 mL). The resulting mixture was shaken for 1 min and then left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative MP-LC.2A Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (3.83 mg, 21%) as a white solid. Purity based on LC-MS 89%. LRMS (m/z): 2409 [M-546]1-, 2955 [M-1]1- LC-MS r.t. (min): 2.661B Intermediate 10: Trifunctional linker (DBCO)-(L-ApoB BNA oligo)-(trivalent GalNAc) (molecule 21) To methyltetrazine-L-ApoB BNA oligo (5.82 mg, 0.684 µmol, molecule 12) and TFL-(DBCO)-(TCO)- (trivalent GalNAc) (2.03 mg, 0.687 µmol, molecule 20) was added 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 1.00 mL). The reaction mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC- MS.4C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (3.73 mg, 64%) as a white fluffy solid. LC-MS shows multiple broad peaks with the correct m/z values. MS (m/z): 8511 [M+H]+ Trifunctional linker (Dendron(-L-hydrazone-SO1861)4)-(L-ApoB BNA oligo)-(trivalent GalNAc synthesis) (molecule 22) To TFL-(DBCO)-(L-ApoB BNA oligo)-(trivalent GalNAc) (1.16 mg, 0.137 µmol; molecule 21) and dendron(-L-SO1861)4-azide (1.39 mg, 0.142 µmol; molecule 19) was added 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 0.5 mL). The reaction mixture was shaken for 1 min and left standing at room temperature. After 3 hours, the reaction mixture was subjected to preparative LC- MS.4B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (1.36 mg, 54%) as a white fluffy solid. Purity based on LC-MS 92% (very broad peak). MS (m/z): 18336 [M+H]+ Using a similar approach as for synthesis of Trifunctional linker (Dendron(-L-hydrazone-SO1861)4)- (L-ApoB BNA oligo)-(trivalent GalNAc synthesis) (molecule 22), a conjugate in which the ApoB BNA was replaced for a BNA with a scrambled ApoB nucleic acid sequence (molecule 12 a) was synthesized (molecule 22a). Trifunctional linker-(dendron(-L-hydrazone-SO1861)8)- (BNA oligo) – (Trivalent-GalNAc) synthesis (Figure 38) Intermediate 11: dendron(-L-SO1861)8-amine (molecule 24) (2S)-N-[(1S)-1-{[2-(6-amino-N-{2-[(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate (0.52 mg, 0.299 µmol, molecule 23) and SO1861-EMCH (29.2 mg, 0.014 mmol, molecule 15) were dissolved in a mixture of 20 mM NH4HCO3 with 0.5 mM TCEP/acetonitrile (3:1, v/v, 1.00 mL). The resulting mixture was shaken for 1 min and then left standing at room temperature. After 30 min, TCEP (0.30 mg, 1.05 µmol) was added and the reaction mixture was shaken for 1 min. Next, the mixture was directly subjected to preparative LC- MS.3B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (2.17 mg, 40%) as a white fluffy solid. Purity based on LC-MS 97%. LRMS (m/z): 2282 [M-8]8-, 2607 [M-7]7- LC-MS r.t. (min): 4.415A Intermediate 12: dendron(-L-SO1861)8-azide (molecule 25) Dendron(-L-SO1861)8-amine (19.6 mg, 1.08 µmol, molecule 24) and 2,5-dioxopyrrolidin-1-yl 1- azido-3,6,9,12-tetraoxapentadecan-15-oate (4.17 mg, 10.8 µmol, molecule 18) were dissolved in DMF (1.50 mL). Next, DIPEA (1.87 µL, 10.8 µmol) was added and the mixture was shaken for 1 min and left standing overnight at room temperature. The reaction mixture was subjected to preparative LC-MS.4B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (11.7 mg, 59%) as a white fluffy solid. Purity based on LC-MS 92% (very broad peak). LRMS (m/z): 2316 [M-8]8-, ): 2647 [M-7]7- LC-MS r.t. (min): 4.291A Trifunctional linker (Dendron(-L-hydrazone-SO1861)8)-(L-ApoB BNA oligo)-(trivalent GalNAc synthesis) (molecule 26) To TFL-(DBCO)-(L-ApoB BNA oligo)-(trivalent GalNAc) (1.16 mg, 0.137 µmol; molecule 21) and dendron(-L-SO1861)8-azide (2.72 mg, 0.142 µmol; molecule 25) was added 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 0.5 mL). The reaction mixture was shaken for 1 min and then left standing at room temperature. After 3 hours, the reaction mixture was subjected to preparative LC- MS.4B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (1.6 mg, 42%) as a white fluffy solid. Purity based on LC-MS 93% (very broad peak). MS (m/z): 27655 [M+H]+ Using a similar approach as for the synthesis of Trifunctional linker (Dendron(-L-hydrazone- SO1861)8)-(L-ApoB BNA oligo)-(trivalent GalNAc synthesis) (molecule 26), a conjugate in which the ApoB BNA was replaced for a BNA with a scrambled ApoB nucleic acid sequence (molecule 12 a) was synthesized (molecule 26a). Trifunctional linker-(L-semicarbazone-SO1861)- (BNA oligo) – (Trivalent-GalNAc synthesis) (Figure 39) Intermediate 13: SO1861-L-semicarbazone-azide (molecule 28) To SO1861 (60 mg, 0.032 mmol, molecule 1) and 4-(6-azidohexanoyl)piperazine-1-carbohydrazide (36.5 mg, 0.129 mmol, molecule 27) was added methanol (extra dry, 1.00 mL) and TFA (9.86 µl, 0.129 mmol). The reaction mixture was shaken for 1 min and then left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative MP- LC.1 Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (30 mg, 44%) as a white fluffy solid. Purity based on LC-MS 99%. MS (m/z): 2126 [M-1]1- Intermediate 14: Trifunctional linker-(L-semicarbazone-SO1861)-(TCO)-(Maleimide) (molecule 29) A solution of TFL-(DBCO)-(TCO)-(Maleimide) (15 mg, 12.5 µmol, molecule 4) in DMF (2.0 mL) was added to SO1861-L-azide (26.6 mg, 12.5 µmol, molecule 28). The reaction mixture was shaken for 30 min and then left standing at room temperature. After 30 min, the reaction mixture was submitted to preparative MP-LC.1C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (27.5 mg, 66%) as a white fluffy solid. Purity based on LC-MS 96%. MS (m/z): 3331 [M-1]1- Intermediate 15: Trifunctional linker-(L-semicarbazone-SO1861)-(TCO)-(trivalent GalNAc) (molecule 30) Trivalent GalNAc-thioacetate (13.0 mg, 7.25 µmol, molecule 8) was dissolved in methanol (0.50 mL). Next, a 1 M solution of sodium hydroxide (7.98 µL, 7.98 µmol) was added. The reaction mixture was shaken for 1 min and then left standing at room temperature. After 30 min, the reaction mixture was added to a freshly prepared solution of TFL-(L-semicarbazone-SO1861)-(TCO)-(maleimide) (20.4 mg, 6.13 µmol, molecule 29) in 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 2.00 mL). The resulting mixture was shaken for 1 min and left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative MP-LC.2A Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (16.7 mg, 54%) as a white solid. Purity based on LC-MS 94%. MS (m/z): 5081 [M-1]1- Trifunctional linker-(L- semicarbazone-SO1861)-(L-BNA oligo)-(trivalent GalNAc) (molecule 31) TFL-(L-semicarbazone-SO1861)-(TCO)-(trivalent GalNAc) (16 mg, 3.15 µmol, molecule 30) and Methyltetrazine-BNA oligo (10.2 mg, 1.83 µmol, molecule 12) were dissolved in a solution of 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 1.00 mL). The reaction mixture was shaken for 1 min and then left standing at room temperature. After 3 hours, the reaction mixture was frozen and lyophilized overnight. The crude product was dissolved in 20 mM ammonium bicarbonate (1 mL) and the resulting solution was directly subjected to preparative LC-MS.1B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (11.3 mg, 59%) as a white fluffy solid. Purity based on LC-MS 92%. MS (m/z): 10638 [M+H]+ Using a similar approach as for synthesis of Trifunctional linker-(L-semicarbazone-SO1861)-(L- BNA oligo)-(trivalent GalNAc) (molecule 31), a conjugate in which the ApoB BNA was replaced for a BNA with a scrambled ApoB nucleic acid sequence (molecule 12 a) can be synthesized (molecule 31a). Trifunctional linker - dendron(L-semicarbazone-SO1861)4 - (L-BNA oligo) - (Trivalent- GalNAc) synthesis (Figure 40) Intermediate 16: benzyl 4-(2-(tert-butoxycarbonyl)hydrazine-1-carbonyl)piperazine-1-carboxylate (molecule 33) To a stirring solution of phosgene in toluene (20%, w/w, 15.8 mL, 30.0 mmol) at 0 °C was slowly added (over 10 min) a solution of 1-Cbz-piperazine (1.93 mL, 10.0 mmol, molecule 1) in dichloromethane (25 mL) and DIPEA (3.83 mL, 22.0 mmol). The reaction mixture was stirred at room temperature. After 30 min, the reaction mixture was evaporated in vacuo and co-evaporated with dichloromethane (2 × 50 mL). Next, the residue was dissolved in dichloromethane (100 mL) and resulting solution was stirred at 0°C. A solution of Boc hydrazine (2.33 mL, 15.0 mmol) in dichloromethane (20 mL) and DiPEA (3.83 mL, 22.0 mL) was added, and the reaction mixture was stirred overnight at room temperature. Next day, the reaction mixture was diluted with dichloromethane (100 mL) and the resulting solution was washed with 0.5 N potassium bisulphate solution (2 × 100 mL) and brine (100 mL), dried over Na2SO4, filtered and evaporated in vacuo. The residue was purified by flash chromatography (first by an ethyl acetate – heptane gradient, 5:95 (v/v) rising to 100% ethyl acetate followed by a flush with 10% methanol in DCM (v/v)) to give the title compound (2.42 g, 64%) as a white solid. Purity based on LC-MS 100%. LRMS (m/z): 279/323/401[M-99/M-55/M+23]1+ LC-MS r.t. (min): 1.271 Intermediate 17: tert-butyl 2-(piperazine-1-carbonyl)hydrazine-1-carboxylate (molecule 34) To benzyl 4-(2-(tert-butoxycarbonyl)hydrazine-1-carbonyl)piperazine-1-carboxylate (2.42 g, 6.39 mmol, molecule 33) was added methanol (50 mL). The mixture was heated to obtain a clear solution. Next, palladium (10% on activated carbon, 50% wet with water, 1.50 g) was added and the resulting mixture was stirred under a hydrogen atmosphere by using a balloon. After 1 hour, the reaction mixture was filtered over celite and the filtrate evaporated in vacuo to give the title product (1.56 g, quant.) as a white solid. LRMS (m/z): 189/245 [M-55/M+1]1+ Intermediate 18: tert-butyl 2-(4-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoyl)piperazine-1- carbonyl)hydrazine-1-carboxylate (molecule 36) 6-maleimidocaproic acid (810 mg, 3.84 mmol, molecule 35), tert-butyl 2-(piperazine-1- carbonyl)hydrazine-1-carboxylate (781 mg, 3.20 mmol, molecule 34), EDCI.HCl (735 mg, 3.84 mmol) and Oxyma Pure (591 mg, 4.16 mmol) were dissolved in a mixture of dichloromethane (25 mL) and DIPEA (835 µL, 4.80 mmol). The reaction mixture was stirred at room temperature. After 2 hours, the reaction mixture was evaporated in vacuo and the residue was dissolved in ethyl acetate (50 mL). The resulting solution was washed with 0.5 N potassium bisulphate solution (50 mL), saturated sodium bicarbonate solution (2 × 50 mL) and brine (50 mL), dried over Na2SO4, filtered and evaporated in vacuo. The residue was purified by flash chromatography (DCM – 10% methanol in DCM (v/v) gradient 100:0 rising to 40:60) to give the title compound (634 mg, 45%) as a white solid. Purity based on LC-MS 97%. LRMS (m/z): 338/382/460 [M-99/M-55/M+23]1+ LC-MS r.t. (min): 1.021 Intermediate 19: SO1861-SC-Mal (molecule 37) tert-butyl 2-(4-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoyl)piperazine-1-carbonyl)hydrazine- 1-carboxylate (25.0 mg, 57.1 µmol, molecule 36) was dissolved in a mixture of dichloromethane (500 µL) and TFA (500 µL). The reaction mixture was stirred at room temperature. After 30 min, the reaction mixture was evaporated in vacuo and co-evaporated with dichloromethane (3 × 5 mL) and methanol (5 mL). The residue and SO1861 (21.3 mg, 11.4 µmol, molecule 1) were dissolved in methanol (extra dry, 1.00 mL), and the resulting mixture was shaken for 1 min and then left standing at room temperature. After 4 hours, the reaction mixture was subjected to to preparative MP-LC.2 Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to yield the title compound (13.7 mg, 55%) as a white fluffy solid. Purity based on LC-MS 97%. LRMS (m/z): 2181 [M-1]1- LC-MS r.t. (min): 2.133 Intermediate 20: dendron(L-semicarbazone-SO1861)4-amine (molecule 39) N,N'-((9S,19S)-14-(6-aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo- 4,11,14,17-tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide) formate (2.73 mg, 3.13 µmol, molecule 38) was dissolved in a mixture of 1M NaOH and MeOH (1:1, v/v, 3.00 mL) and stirred for 30 min. Next, 5 mL of Trimethylphosphine (9.5 mg, 125 µmol) dissolved in THF was added and the mixture was stirred for 30 min. Next, SO1861-SC-Mal (30.54 mg, 0.014 mmol, molecule 37) dissolved in 20 mM NH4HCO3 with acetonitrile (3:1, v/v, 3.00 mL) was added and the reaction mixture was stirred at room temperature. After 1.5 hours, the reaction mixture was subjected to preparative LC-MS.3B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (19 mg, 64 %) as a white fluffy solid. Purity based on LC-MS 95%. MS (m/z): 9553 [M+H]+ Intermediate 21: dendron(-L-SO1861)4-azide (molecule 40) Dendron(L-semicarbazone-SO1861)4-amine (7.1 mg, 0.748 µmol, molecule 39) and 2,5- dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate (2.90 mg, 7.48 µmol, molecule 18) were dissolved in DMF (1.00 mL). Next, DIPEA (1.302 µL, 7.48 µmol) was added and the mixture was shaken for 1 min and then left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (6.4 mg, 87%) as a white fluffy solid. Purity based on LC-MS 93%. MS (m/z): 9826 [M+H]+ Intermediate 22: Trivalent GalNAc-thiol (molecule 41) Trivalent GalNAc-thioacetate (16.2 mg, 9.02 µmol, molecule 8) was dissolved in methanol (500 µL). Next, a 1.00 M solution of sodium hydroxide (11.0 µL, 11.0 µmol) was added. The reaction mixture was shaken for 1 min and then left standing at room temperature. After 30 min, the reaction mixture was submitted to preparative MP-LC.1A Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (13.1 mg, 83%) as a white solid. Purity based on LC-MS 98%. LRMS (m/z): 1748 [M-H]1- LC-MS r.t. (min): 1.781A Intermediate 23: TFL-(DBCO)-(TCO) – (trivalent GalNAc) (molecule 20) TFL-(DBCO)-(TCO)-(Mal) (15.0 mg, 12.4 µmol, molecule 4) was dissolved in acetonitrile (0.50 mL). Next, a solution of 20 mM ammonium bicarbonate (1.50 mL) was added and the resulting solution was directly added to trivalent GalNAc-thiol (22.7 mg, 13.0 µmol, molecule 41). The reaction mixture was shaken for 1 min and then left standing at room temperature. After 1 hour, the reaction mixture was frozen and lyophilized overnight to yield the crude title product as a white solid. Purity based on LC-MS 84%. LRMS (m/z): 2409 [M-546]1-, 2955 [M-1]1- LC-MS r.t. (min): 2.631B Intermediate 24: TFL-(dendron(L-semicarbazone-SO1861)4)-(TCO)-(trivalent GalNAc) (molecule 41) Dendron(L-semicarbazone-SO1861)4-azide (5.2 mg, 0.529 µmol, molecule 40) and TFL-(DBCO)- (TCO)–(trivalent GalNAc) (1.5 mg, 0.5 µmol, molecule 20) were dissolved in DMF (2.00 mL). The mixture was shaken for 10 min and then left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (6.1 mg, 90%) as a white fluffy solid. Purity based on LC-MS 93%. MS (m/z): 12781 [M+H]+ TFL-(-dendron(L-semicarbazone-SO1861)4)-(L-BNA oligo)-(trivalent GalNAc) (molecule 42) TFL-(dendron(L-semicarbazone-SO1861)4)-(TCO)-(trivalent GalNAc) (5.2 mg, 0.41 µmol, molecule 41) and Methyltetrazine-BNA oligo (2.7 mg, 0.5 µmol, molecule 12) were dissolved in a solution of 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 1.00 mL). The reaction mixture was shaken for 1 min and then left standing at room temperature. After 3 hours, the reaction mixture was frozen and lyophilized overnight. The crude product was dissolved in 20 mM ammonium bicarbonate (1 mL) and the resulting solution was directly subjected to preparative LC-MS.1B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (1.8 mg, 24%) as a white fluffy solid. Purity based on LC- MS 96% (multiple (broad) peaks due to regio-isomers). MS (m/z): 18336 [M+H]+ Using a similar approach as for synthesis of Trifunctional linker (Dendron(-L-semicarbazone- SO1861)4)-(L-ApoB BNA oligo)-(trivalent GalNAc synthesis) (molecule 42), a conjugate in which the ApoB BNA was replaced for a BNA with a scrambled ApoB nucleic acid sequence (molecule 12 a) can be synthesized (molecule 42a). Trifunctional linker-(dendron(-L- semicarbazone -SO1861)8)- BNA oligo - Trivalent-GalNAc synthesis (Figure 41) Intermediate 25: dendron(L-semicarbazone-SO1861)8-amine (molecule 44) (2S)-N-[(1S)-1-{[2-(6-amino-N-{2-[(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate (0.61 mg, 0.299 µmol, molecule 43) was dissolved in a mixture of 1M NaOH and MeOH (1:1, v/v, 3.00 mL), and stirred for 30 min. Next, 5 mL of Trimethylphosphine (2 mg, 24 µmol) dissolved in THF was added and the mixture was stirred for another 30 min. Next, SO1861-SC-Mal (30.54 mg, 0.014 mmol, molecule 37) dissolved in 20 mM NH4HCO3 with acetonitrile (3:1, v/v, 3.00 mL) was added and the reaction mixture was stirred at room temperature. After 1.5 hours, the reaction mixture was subjected to preparative LC-MS.3B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (4.6 mg, 81 %) as a white fluffy solid. Purity based on LC-MS 95%. MS (m/z): 19146 [M+H]+ Intermediate 26: dendron(-L-SO1861)8-azide (molecule 45) Dendron(L-semicarbazone-SO1861)8-amine (5.4 mg, 0.28 µmol, molecule 44) and 2,5- dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate (1.1 mg, 2.8 µmol, molecule 18) were dissolved in DMF(1.00 mL). Next, DIPEA (1.302 µL) was added, the mixture was shaken for 1 min and then left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (4.35 mg, 80%) as a white fluffy solid. Purity based on LC-MS 93%. MS (m/z): 19420 [M+H]+ Intermediate 27: TFL-(dendron(L-semicarbazone-SO1861)8)-(TCO)-(trivalent GalNAc) (molecule 46) Dendron(L-semicarbazone-SO1861)8-azide (10.3 mg, 0.529 µmol, molecule 45) and TFL-(DBCO)- (TCO)–(trivalent GalNAc) (1.5 mg, 0.5 µmol, molecule 20) were dissolved in DMF (2.00 mL). The mixture was shaken for 10 min and then left standing at room temperature. After 2 hours, the reaction mixture was subjected to preparative LC-MS.3C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (8.75 mg, 74 %) as a white fluffy solid. Purity based on LC-MS 91%. MS (m/z): 22373 [M+H]+ TFL-(dendron(-L-semicarbazone-SO1861)8)-(L-BNA oligo)-(trivalent GalNAc) (molecule 47) TFL-(dendron(L-semicarbazone-SO1861)8)-(TCO)-(trivalent GalNAc) (9.2 mg, 0.41 µmol, molecule 46) and Methyltetrazine-BNA oligo (2.8 mg, 0.5 µmol, molecule 12) were dissolved in a solution of 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 1.00 mL). The reaction mixture was shaken for 1 min and then left standing at room temperature. After 3 hours, the reaction mixture was frozen and lyophilized overnight. The crude product was dissolved in 20 mM ammonium bicarbonate (1 mL) and the resulting solution was directly subjected to preparative LC-MS.1B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (1.26 mg, 11 %) as a white fluffy solid. Purity based on LC- MS 97%. MS (m/z): 27928 [M+H]+ Using a similar approach as for synthesis of Trifunctional linker (Dendron(-L-semicarbazone- SO1861)8)-(L-ApoB BNA oligo)-(trivalent GalNAc synthesis) (molecule 47), a conjugate in which the ApoB BNA was replaced for a BNA with a scrambled ApoB nucleic acid sequence (molecule 12 a) can be synthesized (molecule 47a). Trivalent linker-(L-SPT001)-(blocked TCO)-(trivalent GalNAc) synthesis (Figure 42) Intermediate 28: N-(2-hydroxyethyl)-2-(4-(6-methyl-1,2,4,5-tetrazin-3-yl)phenyl)acetamide (molecule 50) To a solution of methyltetrazine-NHS ester (30.0 mg, 91.7 µmol, molecule 48) in DMF (1.00 mL) was added ethanolamine (11.1 µL, 0.184 mmol, molecule 49) and triethylamine (25.5 µL, 0.183 mmol). The reaction mixture was shaken for 1 min and then left standing at room temperature. After 1 hour, the reaction mixture was submitted to preparative MP-LC.1B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (19.2 mg, 77%) as a purple solid. Purity based on LC-MS 89%. LRMS (m/z): 274 [M+1]1+ LC-MS r.t. (min): 0.852 TCO blocking on TFL has been performed on the following conjugates: TFL-(L-hydrazone-SPT001)-(blocked TCO)-(trivalent GalNAc) (molecule 51) TFL-(dendron (L-hydrazone-SPT001)4)-(blocked TCO)-(trivalent GalNAc) (molecule 52) TFL-(dendron-(L-hydrazone-SPT001)8)-(blocked TCO)-(trivalent GalNAc) (molecule 53) TFL-(L-semicarbazone-SPT001)-(blocked TCO)-(trivalent GalNAc) (molecule 54) TFL-(dendron((L-semicarbazone-SPT001)4)-(blocked TCO)-(trivalent GalNAc) (molecule 55) TFL-(dendron(L-semicarbazone-SPT001)8)-(blocked TCO)-(trivalent GalNAc) (molecule 56) The procedure is exemplary described for TFL-(L-hydrazone-SPT001)-(blocked TCO)-(trivalent GalNAc) (molecule 51): TFL-(L-hydrazone-SPT001)-(blocked TCO)-(trivalent GalNAc) (molecule 51) A solution of TLF-(DBCO)-(TCO)-(trivalent GalNAc) (36.8 mg, 12.5 µmol, molecule 20) in DMF (2.0 mL) was added to SO1861-L-hydrazone-azide (26.8 mg, 12.5 µmol, molecule 3). The reaction mixture was shaken for 1 min and then left standing at room temperature. After 30 min, N-(2- hydroxyethyl)-2-(4-(6-methyl-1,2,4,5-tetrazin-3-yl)phenyl)acetamide (4.08 mg, 14.9 µmol, molecule 50) was added. The reaction mixture was shaken for 1 min and then left standing at room temperature. After 30 min, the reaction mixture was submitted to preparative MP-LC.1C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (37.3 mg, 56%) as a white fluffy solid. Purity based on LC- MS 96% (double peaks due to regioisomers). LRMS (m/z): 2676 [M-2]2- LC-MS r.t. (min): 2.231B Trifunctional linker-(blocked DBCO)-(L-BNA oligo)-(trivalent GalNAc) synthesis (Figure 43) Intermediate 29: TFL-(blocked DBCO)-(TCO)-(trivalent GalNAc) (molecule 58) A solution of 1-azido-3,6,9-trioxaundecane-11-ol (2.17 mg, 9.88 µmol, molecule 57) in DMF (0.50 mL) was added to TFL-(DBCO)-(TCO)-(trivalent GalNAc) (14.6 mg, 4.94 µmol, molecule 20). The reaction mixture was shaken for 1 min and then left standing at room temperature. After 2 hours, the reaction mixture was submitted to preparative MP-LC.1C Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (10.00 mg, 64%) as a white solid. Purity based on LC-MS 98%. MS (m/z): 3175 [M+H]+ LC-MS r.t. (min): 2.331B Trifunctional linker-(blocked DBCO)-(BNA oligo)-(trivalent GalNAc) (molecule 59) TFL-(blocked DBCO)-(TCO)-(trivalent GalNAc) (10.0 mg, 3.15 µmol, molecule 58) and Methyltetrazine-BNA oligo (10.0 mg, 1.83 µmol, molecule 12) were dissolved in a solution of 20 mM ammonium bicarbonate/acetonitrile (3:1, v/v, 1.00 mL). The reaction mixture was shaken for 1 min and left standing at room temperature. After 3 hours, the reaction mixture was frozen and lyophilized overnight. The crude product was dissolved in 20 mM ammonium bicarbonate (1 mL) and the resulting solution was directly subjected to preparative LC-MS.1B Fractions corresponding to the product were immediately pooled together, frozen and lyophilized overnight to give the title compound (11.3 mg, 72%) as a white fluffy solid. Purity based on LC-MS 95%. LRMS (m/z): 2149 [M-4]4-, 2866 [M-3]3- LC-MS r.t. (min): 2.921A Using a similar approach as for synthesis of Trifunctional linker-(blocked DBCO)-(BNA oligo)- (trivalent GalNAc) (molecule 59), a conjugate in which the ApoB BNA was replaced for a BNA with a scrambled ApoB nucleic acid sequence (molecule 12 a) can be synthesized (molecule 59 a). An overview of all conjugates ‘CONJUGATE C’ (as depicted in the box; the conjugate comprising one of the listed groups for R1 and comprising one of the listed groups R2) produced by applying the Trifunctional linker (TFL) methodology is shown in Figure 44. In addition, a conjugate according to the invention, comprising a single GalNAc moiety, has been synthesized and tested. Luminescence based cell viability assay (Cell Titer Glo - CTG) Cells were incubated for 72 hr at 37°C following compound addition before the cell viability was determined according to the manufacturer’s instruction (CellTiter-Glo® 2.0 Cell Viability Assay, Promega). Briefly, the plate was first equilibrated to RT for 30 minutes. Next, 120 µL CTG solution was added to each well containing 120 µL media. The plate briefly mixed (10 sec, 600 rpm) and incubated for approximately 10 minutes in the dark at RT. Subsequently, the luminescence signal was measured on a Spectramax ID5 plate reader (Molecular Devices). For quantification, the background signal of wells containing only medium was subtracted from all other well values before the cell viability percentage of treated/untreated cells was calculated by dividing the background corrected signal of treated wells by the background corrected signal of the untreated wells (x 100 for percentage). Human primary hepatocyte treatment Cryopreserved primary human hepatocytes (Cytes Biotechnologies S.L., Spain) were thawed in hepatocyte thawing media (Cytes Biotechnologies S.L., Spain). Cells were re-suspended in hepatocyte plating media (Cytes Biotechnologies S.L., Spain). Cells were seeded onto collagen-I coated plates at a density of 215.600 cells/well or 66.600 cells/well for 48 or 96-well plates, respectively (Greiner BioOne). Cells were pre-cultured for 4-6 hrs at 37°C allowing for cell attachment to cell culture plates before test compounds were added. Plating medium was replaced by 315 μl or 108 μl maintenance media (Cytes Biotechnologies S.L., Spain), after which conjugates were added from a 10x concentrated stock solution in PBS. Plates were incubated for 72 hr at 37°C before being harvested for gene expression and cell viability analysis. HSP27BNA, ApoB and ApoBscrambled, and ApoB#02 oligo sequences HSP27 (5’-GGCacagccagtgGCG-3’) [SEQ ID NO: 1]: antisense BNA (HSP27) was a bridged- nucleic acid (BNA) oligonucleotide, more specifically BNANC, with sequence 5’- GGCacagccagtgGCG-3’ modified from Zhang et al. (2011) [Y Zhang, Z Qu, S Kim, V Shi, B Liao1, P Kraft, R Bandaru, Y Wu, LM Greenberger and ID Horak, Down-modulation of cancer targets using locked nucleic acid (LNA)-based antisense oligonucleotides without transfection, Gene Therapy (2011) 18, 326–333]); the apoB-targeting oligonucleotideApoB- (5’-GCCTCagtctgcttcGCACC-3’) [SEQ ID NO: 8] and the control ApoBscrambled (5’-GGCCTctctacaccgCTCGT-3’) [SEQ ID NO: 9], and murine and human sequence-compatible ApoB#02 (5′-GCattggtatTCA-3′) [SEQ ID NO: 10] were all BNANC oligonucleotides and ordered with 5’-Thiol C6 linker at Bio-Synthesis Inc (Lewisville, Texas), with BNANC bases in capitals, and fully phosphorothioated backbones. FACS analysis Cells were seeded in T75 flasks in DMEM (PAN-Biotech GmbH) supplemented with 10% fetal bovine serum (PAN-Biotech GmbH) and 1% penicillin/streptomycin (PAN-Biotech GmbH), at appropriate density for each cell-line and incubated for 72-96 hrs (5% CO2, 37°C), until a confluency of 90% was reached. Next, the cells were trypsinized (TryplE Express, Gibco Thermo Scientific) to obtain a single cell suspension, transferred to a 15 mL falcon tube, and centrifuged (1,400 rpm, 3 min). The supernatant was discarded while leaving the cell pellet submerged.500.000 cells were transferred to round bottom FACS tubes and washed with 3 mL cold DPBS (Mg2+ and Ca2+ free, 2% FBS). The cells were again centrifuged at 1800 rpm, 3 min 4°C and resuspended in 200 µL cold DPBS (Mg2+ and Ca2+ free, 2% FBS) or 200 µL antibody solution, containing 5 µL antibody in 195 µL cold DPBS (Mg2+ and Ca2+ free, 2% FBS). PE anti-human CD71 (#334106, Biolegend) was used to stain the transferrin receptor, PE Mouse IgG2a, κ Isotype Ctrl FC (#400212, Biolegend) was used as its matched isotype control. PE anti-human ASGPR1 (#130-122-963, Miltenyi) was used to stain the ASGPR1 receptor and PE Mouse IgG1, Isotype Ctrl (#130-113-762, Miltenyi) was used as its matched isotype control. Samples were incubated for 30 min at 4°C. Afterwards, the cells were washed 2x with cold DPBS (Mg2+ and Ca2+ free, 2% FBS) and fixated for 20 min at room temperature using a 2% PFA solution in DPBS (Mg2+ and Ca2+ free, 2% FBS). Cells were washed 1x with cold DPBS, and resuspended in 1000 µL cold DPBS for FACS analysis. Samples were analyzed with a Sysmex Cube 8 flow cytometry system (Sysmex) and FCS Express 7 Research edition software. Results of the FACS analyses are summarized in Table A3. Table A3. Cell membrane receptor expression levels of ASGPR1 and CD71 of HepG2 and Huh7 cells
Figure imgf000214_0001
RNA isolation and gene expression analysis from primary mouse and human hepatocytes RNA from cells was isolated using TRI Reagent® Solution (Thermo Scientific) according to the manufacturer’s instruction. Conversion into cDNA was performed using iScript™ cDNA Synthesis Kit (BioRad) using standard protocols. ApoB expression levels and levels of specific hepatocyte housekeeping genes were determined using quantitative real-time PCR assays (qRT-PCR) using iTaq™ Universal SYBR® Green Supermix (BioRad) and the Light Cycler 480 (Roche Diagnostics, Rotkreuz, Switzerland) with gene specific DNA primers, listed in Table A4. Analysis was done by the ΔCt method to determine ApoB expression relative to 2 hepatocyte-specific housekeeping control mRNAs. Each analysis reaction was performed in triplicate. Table A4. Primers used in qPCR analysis of mouse cells/liver tissue (study A)
Figure imgf000215_0001
In vivo tolerability and efficacy of trivalent GalNAc-conjugates in a C57BL/6J model - Dose administration and in-life phase. Per group, 8 C57BL/6J male mice for treatment groups (in study A, 14 mice in vehicle control group), approximately 6 - 7 weeks at arrival and 8 – 9 weeks at dosing, were dosed. The compounds, formulated in PBS or PBS alone (vehicle) according to Table A5 and Table A6, were dosed at 5 ml/kg in the tail vain (intravenously, i.v.), with dose volumes corresponding to the individual bodyweights. Where applicable, trivalent (GalNAc)3-SO1861 (EMCH) was co-administered at 5 ml/kg in the tail vain (i.v.) right after the trivalent GalNAc-ApoB conjugate. Animals were weighed weekly and clinical observations were performed 2 – 3 times daily within the first 48 hrs, and at least once daily thereafter until study end. - Sampling of serum, liver, and kidney tissue. Blood was sampled before dosing (predose) and at indicated post-dose timepoints (e.g., 24 hrs, 72 hrs, 196 hrs, 336 hrs, 672 hrs post dose), and serum was generated from the collected blood for biomarker analysis, using standard procedures. At the relevant inter-study post-dose timepoints, 3 animals per timepoint per treatment group (6 animals in the vehicle control group in study A) were sacrificed to collect terminal bleeds and collect relevant organs, such as liver and kidney tissues for further analyses. At the end of the study, the remaining 2 animals (4 in the control group in study A) per group were sacrificed. One half of the liver and one kidney was frozen and used for tissue RNA analysis. Table A5. Experimental design in vivo tolerability and efficacy of trivalent GalNAc-conjugates (study A)
Figure imgf000216_0001
Table A6. Experimental design in vivo tolerability and efficacy of trivalent GalNAc-conjugates (study B)
Figure imgf000217_0001
Biomarker RNA analysis in liver tissue The mRNA was isolated from frozen liver tissue using TRIzol® Reagent (Thermo Scientific) according to the manufacturer’s instruction. Conversion into cDNA was performed using iScript™ cDNA Synthesis Kit (BioRad). ApoB expression levels and levels of specific liver housekeeping genes were determined using quantitative real-time PCR assays (qRT-PCR) using iTaq™ Universal SYBR® Green Supermix (BioRad) and the Light Cycler 480 (Roche Diagnostics, Rotkreuz, Switzerland) with gene specific DNA primers, listed in Table A4 (study A) and Table A7 (study B), respectively. Analysis was done by the ΔCt method to determine ApoB expression relative to 2 liver-specific housekeeping control mRNAs. Each analysis reaction was performed in triplicate. Table A7. Primers used in qPCR analysis of liver tissue (study B)
Figure imgf000218_0001
Biomarker RNA analysis in liver tissue The mRNA was isolated from frozen liver tissue using TRIzol® Reagent (Thermo Scientific) according to the manufacturer’s instruction. Conversion into cDNA was performed using iScript™ cDNA Synthesis Kit (BioRad). ApoB expression levels and levels of specific liver housekeeping genes were determined using quantitative real-time PCR assays (qRT-PCR) using iTaq™ Universal SYBR® Green Supermix (BioRad) and the Light Cycler 480 (Roche Diagnostics, Rotkreuz, Switzerland) with gene specific DNA primers, listed in Table A4 (study A) and Table A7 (study B). Analysis was done by the ΔCt method to determine apoB expression relative to 2 liver-specific housekeeping control mRNAs. Each analysis reaction was performed in triplicate. Biomarker analysis ApoB protein ApoB protein levels in mouse serum was determined using an ApoB ELISA (ab230932, Abcam, Cambridge, UK), according to the manufacturer’s instruction. Biomarker analysis LDL cholesterol LDL-cholesterol was measured in mouse serum, using an LDL-cholesterol specific two-step AU480 assay kit, respectively, from Beckman Coulter, with a photometric measurement according to the manufacturer’s instructions. Biomarker ALT level analysis Serum alanine transaminase (ALT) levels was measured using an AU480 assay kit from Beckman Coulter (photometric measurements), according to the manufacturer’s instructions. Results In vitro potency of (GalNAc)3-SO1861-ApoB#02 BNA An apoB-targeting BNA, ApoB#02 (SEQ ID NO: 10), and SO1861-EMCH or SO1861-sc- Mal were conjugated to trivalent-GalNAc ((GalNAc)3) (Figure 34, Figure 35) to produce (GalNAc)3- SO1861-ApoB#02 (EMCH) (Figure 36) and (GalNAc)3-SO1861-ApoB#02 (sc) (Figure 39). (GalNAc)3-SO1861 (Figure 42; referred to as ‘Trivalent linker-(L-SPT001)-(blocked TCO)-(trivalent GalNAc)’, Figure 44) and (GalNAc)3-ApoB#02 BNA (Figure 43; referred to as ‘Trivalent linker- (blocked DBCO)-(L-BNA oligo)-(trivalent GalNAc)’, Figure 44) and conjugates were tested on primary human hepatocytes, as well as HepG2 (ASGPR+) and Huh7 (ASGPR+/-) cell lines to assess their effect on apoB mRNA levels. In primary hepatocytes, this assessment revealed that (GalNAc)3-SO1861-ApoB#02 (EMCH) and (GalNAc)3-SO1861-ApoB#02 (sc) showed an IC50 of 1 nM (relative ApoB#02 BNA concentration), whereas (GalNAc)3- ApoB#02 BNA without SO1861 showed an IC50 = 7 nM (relative ApoB#02 BNA concentration), and ApoB#02 BNA transfection with RNAi-MAX showed an IC50 = 8 nM. ApoB#02 alone (without any transfection agent) showed an IC50 = 400 nM, while (GalNAc)3-SO1861 had no effect on apoB RNA levels (Figure 24A). All this shows that (GalNAc)3- SO1861-ApoB#02 enhances the cytoplasmic delivery of the ApoB#02 BNA in human primary hepatocytes, resulting in around 10-fold improved potency at low nM levels of ApoB#02 BNA oligonucleotide. Covalent binding of the saponin to the GalNAc/oligonucleotide conjugate via a semicarbazone bond thus results in increased efficacy when relative apoB mRNA levels are compared with levels in cells treated with a conjugate where saponin was linked to the GalNAc/oligonucleotide conjugate via a hydrazone bond. Without wishing to be bound by any theory, improved efficacy of the release of free saponin from the conjugate, when the conjugate is transferred into the endosome, is at the basis for the improved potency of the oligonucleotide, as obtained with the conjugate comprising saponin bound via semicarbazone. For HepG2 cells (ASGPR1+), only ((GalNAc)3-SO1861-ApoB#02 (EMCH) and (GalNAc)3- SO1861-ApoB#02 (sc) showed activity at the concentrations tested (IC50 = 40 nM and IC50 = 20 nM, respectively) (Figure 24B), whereas in Huh7 cells (ASGPR1+/-), (GalNAc)3-SO1861-ApoB#02 (EMCH) showed activity at IC50 = 100 nM and (GalNAc)3-SO1861-ApoB#02 (sc) showed activity at IC50 = 40 nM (Figure 24C). In vivo efficacy of (GalNAc)3-SO1861-ApoB#02 in C57BL/6J mice (study A) In study A, C57BL/6J mice were treated as described and dosed according to Table A5. The conjugates used in this study, (GalNAc)3-ApoB#02 (Figure 43; referred to as ‘Trivalent linker- (blocked DBCO)-(L-BNA oligo)-(trivalent GalNAc)’, Figure 44), (GalNAc)3-SO1861 (Figure 42; referred to as ‘Trivalent linker-(L-SPT001)-(blocked TCO)-(trivalent GalNAc)’, Figure 44), (GalNAc)3-SO1861-ApoB#02 (EMCH) (Figure 35) and (GalNAc)3-SO1861-ApoB#02 (sc) (Figure 39) were produced as described elsewhere in the Examples. Clinical observations were recorded and different biomarkers of efficacy and tolerability were analysed. As Figure 25 shows, after 24 hrs, hepatic apoB mRNA levels, i.e. gene expression, was not noticeably reduced in animals treated with 0.1 mg/kg ApoB#02 BNA (ApoB#02), and ca.15% and 21% reduced in groups dosed with 1 mg/kg or 2 mg/kg ApoB#02 BNA, respectively (all n = 3 animals per group), compared to the vehicle-dosed group (n = 5 animals). Likewise, (GalNAc)3- ApoB#02, at a dose of 1 mg/kg (corresponding to 0.54 mg/kg ApoB#02 BNA) reduced apoB expression by ca.53% (n = 3 animals) compared to the vehicle control after 24 hrs, while 0.1 mg/kg (GalNAc)3-ApoB#02 alone did not show a noticeable reduction (n = 3) compared to vehicle. In contrast, when 0.1 mg/kg (GalNAc)3-ApoB#02 was co-administered with 5 mg/kg (GalNAc)3- SO1861, apoB expression was readily reduced by ca.69% (n = 2 animals) already after 24 hrs; while 0.01 mg/kg (GalNAc)3-ApoB#02, when co-administered with 5 mg/kg (GalNAc)3-SO1861 still show a minor reduction of 16% (n = 2 animals), compared to vehicle. Most notably, treatment with 1 mg/kg (GalNAc)3-SO1861-ApoB#02 BNA (corresponding to 0.44 mg/kg ApoB#02 BNA) resulted in a ca.77% reduction for (GalNAc)3-SO1861-ApoB#02 BNA (EMCH) and even more, namely a 90% reduction, for (GalNAc)3-SO1861-ApoB#02 BNA (sc), compared to control already 24 hrs post dosing (n = 3 animals in both groups each). Covalent binding of the saponin to the GalNAc/oligonucleotide conjugate via a semicarbazone bond thus results in increased efficacy when relative apoB mRNA levels are considered and compared with levels measured for control animals which were treated with conjugate comprising saponin linked via a hydrazone bond to the GalNAc/oligonucleotide conjugate. Without wishing to be bound by any theory, improved efficacy of the release of free saponin from the conjugate, when the conjugate is transferred into the endosome, is at the basis for the improved potency of the oligonucleotide, as obtained with the conjugate comprising saponin bound via semicarbazone. After 72 hrs, the highest dose of ApoB#02 BNA administered (2 mg/kg) showed a maximal reduction of 39% (n = 3 animals) compared to vehicle (n = 5 animals), while 1 mg/kg (GalNAc)3- ApoB#02 resulted in a 68% reduction of apoB expression (n = 3 animals). Again, in contrast, the 10-fold lower dose of 0.1 mg/kg (GalNAc)3-ApoB#02, when co-administered with 5 mg/kg (GalNAc)3-SO1861, resulted in even 82% reduction of apoB expression levels (n = 3 animals), while 0.1 mg/kg (GalNAc)3-ApoB#02 alone only shows 12% reduction (n = 3 animals). Here, treatment with 1 mg/kg (GalNAc)3-SO1861-ApoB#02 BNA resulted in ca. 76% reduction for (GalNAc)3-SO1861-ApoB#02 BNA (EMCH) and even a 96% reduction for (GalNAc)3-SO1861- ApoB#02 BNA (sc) (n = 3 animals in both groups each). The effect was durable, and after 336 hrs, apoB expression levels were reduced by 30% for 2 mg/kg ApoB#2 BNA (n = 2 animals) and 25% for 1 mg/kg (GalNAc)3-ApoB#02. The co-administration group of 10-fold less payload (i.e., 0.1 mg/kg (GalNAc)3-ApoB#02 + 5 mg/kg (GalNAc)3-SO1861 still showed 25% decrease. Treatment with 1 mg/kg (GalNAc)3-SO1861-ApoB#02 BNA resulted in ca. 61% reduction for (GalNAc)3- SO1861-ApoB#02 BNA (EMCH) and a 65% reduction for (GalNAc)3-SO1861-ApoB#02 BNA (sc) (n = 3 animals in both groups each). In conclusion, conjugation of SO1861 markedly improves potency, and conjugates with SC-SO1861 specifically, meaning (GalNAc)3-SO1861-ApoB#02 BNA (sc), result in the most potent down-modulation at the same payload (ApoB BNA) dose per kg. As Figure 26 shows, the apoB mRNA down-modulation in the liver (shown in Figure 25) also translated to apoB protein reduction in serum. After 24 hrs, the apoB protein levels were reduced by over 50% for both, the 1 mg/kg (GalNAc)3-ApoB#02 (n = 8 animals, 54% reduction) and equally so for the co-administration group with 10-fold less (GalNAc)3-ApoB#02 + 5 mg/kg (GalNAc)3- SO1861, i.e., 0.1 mg/kg (GalNAc)3-ApoB#02 + 5 mg/kg (GalNAc)3-SO1861 (n = 8 animals, 56% reduction); most notably, apoB protein levels were reduced for 1 mg/kg (GalNAc)3-SO1861- ApoB#02 (EMCH) group (n = 8 animals, 69% reduction) and to an even higher extent of 83% for 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (sc) group (n = 8 animals) compared to controls (n = 14 animals). After 72 hours, while all treatment groups showed reduction in apoB protein, compared to vehicle controls, the most pronounced effect was observed for 1 mg/kg (GalNAc)3-SO1861- ApoB#02 (EMCH) group (n = 5 animals, 95% reduction) and, to an even higher extent, for the 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (sc) group (n = 5 animals, as much as 97% reduction) or when co-administering 0.1 mg/kg (GalNAc)3-ApoB#02 with 5 mg/kg (GalNAc)3-SO1861, resulting in an apoB reduction of almost 90% (n = 5 animals). Even doses as low as 0.01 mg/kg (GalNAc)3- ApoB#02 reduced apoB protein by ca. 25% when co-administering it with 5 mg/kg (GalNAc)3- SO1861 (n = 4 animals), while the 10-fold higher dose of 0.1 mg/kg (GalNAc)3-ApoB#02 alone reduced apoB protein by 35% (n = 5 animals) after 72 hrs post-dose. The effect was durable and apoB protein reduction was still observable at 192 hrs and 336 hrs for all treatment groups analyzed; NB, levels for 0.1 mg/kg ApoB#02 (196 hrs), 0.01 mg/kg (GalNAc)3-ApoB + 5 mg/kg (GalNAc)3- SO1861 (196 hrs and 336 hrs) and 0.1 mg/kg (GalNAc)3-ApoB + 5 mg/kg (GalNAc)3-SO1861 (196 hrs) are not reported. At 192 hrs, 0.1 mg/kg (GalNAc)3-ApoB#02 + 5 mg/kg (GalNAc)3-SO1861 showed 55% reduction (n = 2 animals), 1 mg/kg (GalNAc)3-ApoB#02 showed 47% reduction (n = 2 animals) but 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (EMCH) and 1 mg/kg (GalNAc)3-SO1861- ApoB#02 (sc) showed 87% and 90% reduction, respectively (n = 2 animals per group). At 336 hrs, 0.1 mg/kg (GalNAc)3-ApoB#02 with 5 mg/kg (GalNAc)3-SO1861 showed still 29% reduction (n = 2 animals), 1 mg/kg (GalNAc)3-ApoB#02 showed 28% reduction (n = 2 animals) but 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (EMCH) and 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (sc) showed still 66% and 65% reduction, respectively (n = 2 animals per group). Similar to the results obtained with testing for apoB gene expression, covalent binding of the saponin to the GalNAc/oligonucleotide conjugate via a semicarbazone bond thus results in increased efficacy when relative apoB protein levels in serum are considered and compared with levels measured for animals which were treated with conjugate where saponin was linked to the GalNAc/oligonucleotide conjugate via a hydrazone bond. Without wishing to be bound by any theory, improved efficacy of the release of free saponin from the conjugate, when the conjugate is transferred into the endosome, is at the basis for the improved potency of the oligonucleotide, as obtained with the conjugate comprising saponin bound via semicarbazone. As Figure 27 shows, the observed serum apoB protein reduction (shown in Figure 26) translated also to a reduction in serum LDL-cholesterol (LDL-C) levels. After 24 hrs, LDL-C levels were not noticeably reduced in animals treated with either 0.1, 1, or 2 mg/kg ApoB#02 BNA (n = 3 animals per group) compared to vehicle (n = 5 animals). Targeted (GalNAc)3-ApoB#02 at a dose of 1 mg/kg reduced LDL-C to an average of 2.7 mg/dl within 24 hrs already (n = 3 animals), i.e., a 53% reduction compared to vehicle and ApoB#02 BNA groups. The same reduction of LDL-C to an average of 2.7 mg/dl within 24 hrs (n = 3 animals), i.e. a 53% reduction, was already observed with a 10-fold lower dose of 0.1 mg/kg (GalNAc)3-ApoB#02 when co-administering it with 5 mg/kg (GalNAc)3-SO1861, while 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (EMCH) and 1 mg/kg (GalNAc)3- SO1861-ApoB#02 (sc) showed a reduction of 66% and even as high as 77%, respectively. After 72 hrs, the highest dose of ApoB#02 BNA (2 mg/kg) showed a ca.50% reduction (n = 3 animals) in LDL-C compared to vehicle (n = 5 animals), while for the 1 mg/kg (GalNAc)3-ApoB#02 group, LDL- C was 72% reduced (n = 3 animals), and the 10-fold lower dose of 0.1 mg/kg (GalNAc)3-ApoB#02 + 5 mg/kg (GalNAc)3-SO1861 was even 78% reduced (n = 3 animals); 1 mg/kg (GalNAc)3- SO1861-ApoB#02 (EMCH) showed 72% reduction, while in the 1 mg/kg (GalNAc)3-SO1861- ApoB#02 (sc), no LDL-C above limit of detection (i.e., zero) remained measurable, i.e., a surprisingly high extent of 100% reduction in apoB protein compared to control (all n = 3 animals). The effect was durable, and after 336 hrs, LDL-C levels were still reduced (in n = 2 animals for all groups) by ca.40% for 2 mg/kg ApoB#02 BNA, and 48% for both, the 1 mg/kg (GalNAc)3-ApoB#02 and for the co-administration group of 0.1 mg/kg (GalNAc)3-ApoB#02 + 5 mg/kg (GalNAc)3- SO1861, showing a 10-fold improved LDL-C reduction based in administered payload in the latter. Again, the most pronounced reductions were observed in the groups with 1 mg/kg (GalNAc)3- SO1861-ApoB#02 (EMCH) with 74% reduction and 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (sc) showed a reduction of 57%. In conclusion, this shows that in combination with SO1861, and SC-SO1861 specifically, the potency of ApoB#02 is markedly increased and is effectively inducing apoB mRNA reduction, i.e., gene silencing in the livers of C57BL/6J mice, and reduction of all ‘downstream’ serum biomarkers of efficacy, such as apoB protein and LDL-cholesterol. In vivo tolerability of (GalNAc)3- SO1861-ApoB#02 in C57BL/6J mice The conjugates used in this study, (GalNAc)3-ApoB#02 (Figure 43, Figure 44), (GalNAc)3- SO1861 (Figure 42, Figure 44), (GalNAc)3-SO1861-ApoB#02 (EMCH) (Figure 36) and (GalNAc)3-SO1861-ApoB#02 (sc) (Figure 39) were produced and dosed as described in Table A5. During the course of the study, all treatments, doses, and dose regimens as described in Table A5 were well tolerated and showed no treatment-specific adverse findings or any specific clinical observations indicative of the conjugates not being tolerated. The mice in treatment groups gained weight comparable to the mice receiving vehicle. Serum ALT levels were determined and results are shown in Figure 28. During the study period, ALT levels for vehicle mice ranged from an average 47 to 61 U/L per group (n = 5 animals for vehicle). Levels of ALT transiently increased in the different dose groups at different time points, with sometimes large per-animal variation per group, without showing specific compound or dose relationship (n = 3 for all groups at 24 hrs and 72 hrs, respectively, except for 0.01 mg/kg (GalNAc)3-ApoB#02 + 5 mg/kg (GalNAc)3-SO1861, where n = 2 for both time points). Notably, after 336 hrs, ALT levels in all dosing groups were back to baseline and comparable to vehicle controls (n = 2 for all groups). In conclusion, this shows that ApoB#02, (GalNAc)3-ApoB#02, (GalNAc)3-SO1861 (alone or in combination with (GalNAc)3-ApoB#02), and (GalNAc)3-SO1861-ApoB#02 (EMCH) and (GalNAc)3-SO1861-ApoB#02 (sc) are well tolerated in the doses and dose regimen applied, and particularly, that administration of SO1861-containing conjugates (GalNAc)3-SO1861-ApoB#02 (EMCH) and (GalNAc)3-SO1861-ApoB#02 (sc) as well as co-administration of (GalNAc)3-SO1861 with (GalNAc)3-ApoB#02 has no immediate tolerability issues, while showing high potency in the C57BL/6J mouse model. In vitro potency of (GalNAc)3-d(SO1861)8-ApoB#02 An apoB-targeting BNA, ApoB#02 (SEQ ID NO: 10), and SO1861-EMCH or SO1861-sc- Mal was conjugated to trivalent-GalNAc ((GalNAc)3) (Figure 34, Figure 35) to produce (GalNAc)3- SO1861-ApoB#02 (EMCH) (Figure 36), (GalNAc)3-SO1861-ApoB#02 (sc) (Figure 39), (GalNAc)3- d(SO1861)4-ApoB#02 (sc) (Figure 40), (GalNAc)3-d(SO1861)8-ApoB#02 (sc) (Figure 41, also named (GalNAc)3-dSPT8-ApoB#02)) and (GalNAc)3-ApoB#02 BNA (Figure 43, (GalNAc)3- dSPT8-ApoB#02)).Conjugates were tested on primary human hepatocytes to assess their effect on apoB mRNA levels. In primary hepatocytes, this assessment revealed that (GalNAc)3-d(SO1861)8- ApoB#02 (sc) showed an IC50 of 1.5 nM (relative conjugate concentration), whereas (GalNAc)3- SO1861-ApoB#02 (EMCH), (GalNAc)3-SO1861-ApoB#02 (sc), (GalNAc)3-d(SO1861)4-ApoB#02 (sc) or (GalNAc)3-ApoB#02 were less potent (IC50 between 5-8 nM) (Figure 29). All this shows that increased numbers of SO1861 molecules per GalNAc conjugate enhances the potency of the conjugate, thereby reducing the amounts of ApoB#02 BNA payload that is needed to reduce the levels of apoB mRNA. This is in favor of a broadened therapeutic window when the potency of the oligonucleotide is considered, under influence of an increased number of saponin moieties present in the conjugate comprising saponin, oligonucleotide and a target-cell ligand (GalNAc). In vivo efficacy of (GalNAc)3-SO1861-ApoB#02 in C57BL/6J mice (study B) In study B, C57BL/6J mice were treated as described and dosed according to Table A6. The conjugates used in this study, (GalNAc)3-SO1861-ApoB#02 (sc), (GalNAc)3-d(SO1861)4-ApoB#02 (sc), (GalNAc)3-d(SO1861)8-ApoB#02 (sc), (GalNAc)3-ApoB#02 and (GalNAc)3-SO1861) were produced as described in Figure 39, Figure 40, Figure 41, Figure 42, Figure 43. Clinical observations were recorded and different biomarkers of efficacy and tolerability were analysed. As Figure 30 shows, after 72 hrs, the apoB mRNA levels, i.e. gene expression, was reduced in animals treated with the benchmark 2 mg/kg ApoB#02 BNA (53% from control), but was even more reduced (to 24% and 21% of vehicle control, respectively) in the groups dosed with (1 mg/kg (GalNAc)3-ApoB#02 + 0.1 mg/kg (GalNAc)3-SO1861) and with 1 mg/kg (GalNAc)3-SO1861- ApoB#02 (sc), respectively, showing the markedly improved potency when adding SO1861 to the conjugate (n = 3 animals per group). Moreover, when increasing the saponin-per-payload, by dosing 10-times less payload (0.173 mg/kg (GalNAc)3-d(SO1861)4-ApoB#02 (sc), (for brevity reasons, in the Figure 30 the dose is displayed as 0.1 mg/kg) also named (GalNAc)3-dSPT4- ApoB#02 (sc) or 0.265 mg/kg (GalNAc)3-d(SO1861)8-ApoB#02 (sc), also named GalNAc)3-dSPT8- ApoB#02 (sc)), corresponding to the same payload doses (i.e., 0.044 mg/kg ApoB#02 BNA) contained in 0.1 mg/kg (GalNAc)3-SO1861-ApoB#02 (sc), but 4-times and 8-times more SO1861, respectively, apoB expression was reduced to 74% and 38%, respectively, while it was 89% of control for 0.1 mg/kg (GalNAc)3- SO1861-ApoB#02 (sc). This showsthat an increase of saponin DAR markedly increases potency of the conjugate. A decrease of saponin amount (0.1 mg/kg (GalNAc)3- SO1861 (sc) + 0.1 mg/kg (GalNAc)3-ApoB#02) yielded less potency (71% apoB expression compared to vehicle). After 336 hrs, the effect of expression downmodulation was still preserved in the 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (sc) dose group and was 49% of vehicle control (n=3 mice). As Figure 31 shows, the apoB mRNA down-modulation in the liver (shown in Figure 30) also translated to apoB protein reduction in serum. Predose levels ranged from 156 – 198 µg/ml over the groups (n = 8 per group). At 72 hrs post-dose, the apoB protein levels were reduced in animals treated with the benchmark 2 mg/kg ApoB#02 BNA (57 µg/ml average compared to 156 µg/ml of the vehicle control), but was even more reduced (to 18 µg/ml and 21 µg/ml of vehicle control, respectively) in the groups dosed with (1 mg/kg (GalNAc)3-ApoB#02 + 0.1 mg/kg (GalNAc)3- SO1861) and with 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (sc), respectively, showing the markedly improved potency when adding SO1861 to the conjugate (n = 8 animals per group). As with the RNA levels, when increasing the saponin-per-payload, by dosing 0.173 mg/kg (GalNAc)3- d(SO1861)4-ApoB#02 (sc) or 0.265 mg/kg (GalNAc)3-d(SO1861)8-ApoB#02 (sc), respectively, serum apoB protein was reduced to 89 µg/ml and 50 µg/ml, respectively, while it was 141 µg/ml for 0.1 mg/kg (GalNAc)3- SO1861-ApoB#02 (sc), again showing that an increase of saponin markedly increases potency of the conjugate in reducing apoB protein. A decrease of saponin amount (0.1 mg/kg (GalNAc)3-SO1861 (sc) + 0.1 mg/kg (GalNAc)3-ApoB#02) yielded less potency (122 µg/ml apoB protein). After 336 hrs, the effect of protein reduction was still preserved in the 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (sc) dose group and was 59 µg/ml, compared to 143 µg/ml in the vehicle control (n=5 mice in all groups); at 672 hrs, apoB protein levels varied between 100 – 152 µg/ml in all grops (n = 2 mice). As Figure 32 shows, the observed serum apoB protein reduction (shown in Figure 31) translated well to serum LDL-cholesterol (LDL-C) levels. At 72 hrs post-dose, the LDL-C levels were reduced in animals treated with the benchmark 2 mg/kg ApoB#02 BNA (2 mg/dl compared to 4 mg/dl of the vehicle control), but was even more reduced (to 0.7 mg/dl and 1.3 mg/dl µg/ml, respectively) in the groups dosed with (1 mg/kg (GalNAc)3-ApoB#02 + 0.1 mg/kg (GalNAc)3- SO1861) and with 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (sc), respectively, showing the markedly improved potency when adding SO1861 to the conjugate (n = 3 animals per group). As with the apoB mRNA and apoB protein levels, when increasing the saponin-per-payload, by dosing 0.173 mg/kg (GalNAc)3-d(SO1861)4-ApoB#02 (sc) or 0.265 mg/kg (GalNAc)3-d(SO1861)8-ApoB#02 (sc), respectively, LDL-C was reduced to 2.3 mg/dl and 1.3 mg/dl, respectively, while it was 4.3 mg/dl for 0.1 mg/kg (GalNAc)3- SO1861-ApoB#02 (sc), showing that an increase of saponin markedly increases potency of the conjugate in reducing LDL-C. A decrease of saponin amount (0.1 mg/kg (GalNAc)3- SO1861 (sc) + 0.1 mg/kg (GalNAc)3-ApoB#02) yielded lower potency (3.7 mg/dl LDL- C). After 336 hrs, the effect of LDL-C reduction was still preserved in the 1 mg/kg (GalNAc)3- SO1861-ApoB#02 (sc) dose group (2 mg/dl; n = 3 animals) and in the (1 mg/kg (GalNAc)3-ApoB#02 + 0.1 mg/kg (GalNAc)3-SO1861), where it was 3.3 mg/dl (n = 3 animals). Showing the durability of the effect; at 672 hrs, LDL-C levels varied between 3 – 4 mg/dl in all grops (n = 2 mice). In conclusion, this shows that in combination with SO1861, the potency of ApoB#02 is markedly increased, and mostly so in SC-SO1861-containing conjugates, and is effectively inducing apoB mRNA down-modulation, i.e., gene silencing in the livers of C57BL/6J mice, and of all ‘downstream’ serum biomarkers of efficacy measured, such as apoB protein and LDL-cholesterol. In vivo tolerability of (GalNAc)3- SO1861-ApoB#02 in C57BL/6J mice (study B) The conjugates used in this study, (GalNAc)3-SO1861-ApoB#02 (sc), (GalNAc)3-d(SO1861)4- ApoB#02 (sc), (GalNAc)3-d(SO1861)8-ApoB#02 (sc), (GalNAc)3-ApoB#02 and (GalNAc)3- SO1861) were produced as described in Figure 39, Figure 40, Figure 41, Figure 42, Figure 43. During the course of the study, all treatments, doses, and dose regimens as described in Table A6 were well tolerated and showed no treatment-specific adverse findings or any specific clinical observations or gross organ morphology indicative of the conjugates not being tolerated. The mice in treatment groups gained weight comparable to the mice receiving vehicle. Serum ALT levels were determined and results are shown in Figure 33. Levels of ALT appeared to transiently increase in the 0.173 mg/kg (GalNAc)3-d(SO1861)4-ApoB#02 (sc) group at 72 hrs but returned to levels of vehicle control by 336 hrs post-dose; likewise, it increased in the 0.265 mg/kg (GalNAc)3-d(SO1861)4-ApoB#02 (sc) group, but reurned to vehicle levels at later timepoints post- dose. Notably, 1 mg/kg (GalNAc)3-SO1861-ApoB#02 (sc) showed no elevation post-dose up to 336 hrs but was measured at 166 U/L at 672 hrs (n = 2 mice). In conclusion, this data shows that the saponin conjugates are well tolerated in the doses and dose regimen applied, and particularly, that administration of SO1861-containing conjugates (GalNAc)3- SO1861-ApoB#02 (sc), (GalNAc)3-d(SO1861)4-ApoB#02 (sc), and (GalNAc)3-d(SO1861)8- ApoB#02 (sc), as well as co-administration of (GalNAc)3-SO1861 with (GalNAc)3-ApoB#02 has no immediate tolerability issues, while showing high potency in the C57BL/6J mouse model.

Claims

CLAIMS 1. Saponin derivative based on a saponin comprising a triterpene aglycone core structure and at least one of a first saccharide chain ‘R1’ and a second saccharide chain ‘R2’ linked to the aglycone core structure, wherein the saponin derivative comprises an aglycone core structure comprising an aldehyde group, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (I)
Figure imgf000226_0001
() wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, X = O, P or S, and Y = NR3R4, wherein R3 and R4 independently represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, preferably one of R3 and R4 is H; or
Figure imgf000226_0002
wherein n and m each are an integer independently selected from 1, 2, or 3, Z = CH2, O, S, P or NR5, and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl, an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000226_0003
or an azide moiety according to formula (II)c
Figure imgf000226_0004
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6, and W is a thiol functional group according to formula (III)
Figure imgf000227_0001
( ) wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2.
2. Saponin derivative according to claim 1, wherein the saponin on which the saponin derivative is based is a mono-desmosidic or bi-desmosidic triterpene saponin belonging to the type of a 12,13-dehydrooleanane with the aldehyde group in position C-23 and optionally comprising a glucuronic acid group in a carbohydrate substituent at the C-3beta-OH group of the saponin, preferably a bi-desmosidic triterpene saponin belonging to the type of a 12,13-dehydrooleanane with the aldehyde group in position C-23 and comprising a glucuronic acid group in a carbohydrate substituent at the C-3beta-OH group of the saponin.
3. Saponin derivative according to claim 1 or 2, wherein the saponin derivative is according to formula (IV):
Figure imgf000227_0002
wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide, X = O, P or S, and Y = NR3R4, wherein R3 and R4 independently represent H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, preferably one of R3 and R4 is H; or
Figure imgf000228_0001
, wherein n and m each are an integer independently selected from 1, 2 or 3; Z = CH2, O, S, P or NR5, and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000228_0002
(II)a (II)b or an azide moiety according to formula (II)c
Figure imgf000228_0003
wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6 and W is a thiol functional group according to formula (III)
Figure imgf000228_0004
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2.
4. Saponin derivative according to any one of the claims 1-3, wherein X = O.
5. Saponin derivative according to any one of the claims 1-4, wherein
Figure imgf000228_0005
n and m each are an integer independently selected from 1, 2 or 3; and Z = CH2, O, S, P or NR5; and wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000229_0001
(II)a (II)b or an azide moiety according to formula (II)c
Figure imgf000229_0002
(II)c wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6 and W is a thiol functional group according to formula (III)
Figure imgf000229_0003
( ) wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2.
6. Saponin derivative according to any one of the claims 1-5, wherein
Figure imgf000229_0004
n and m each are an integer independently selected from 1, 2 or 3; and Z = O or NR5; wherein R5 represents H, an unsubstituted C1 – C10 straight chain, branched or cyclic alkyl, an unsubstituted C2 – C10 straight chain, branched or cyclic alkenyl or an unsubstituted C2 – C10 straight chain or branched alkynyl, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000230_0001
(II)a (II)b or an azide moiety according to formula (II)c
Figure imgf000230_0002
(II)c wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6 and W is a thiol functional group according to formula (III)
Figure imgf000230_0003
wherein U = SH, NH2 or OH and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2.
7. Saponin derivative according to any one the claims 1-6, wherein
Figure imgf000230_0005
; n and m each are an integer independently selected from 1, 2 or 3; and Z = O or NR5; wherein R5 represents H, or a covalently bound linker, or a maleimide moiety according to formula (II)a or formula (II)b
Figure imgf000230_0004
or an azide moiety according to formula (II)c
Figure imgf000231_0001
(II)c wherein o is an integer selected from 0-10, preferably 2-7, more preferably 4-6 and W is a thiol functional group according to formula (III)
Figure imgf000231_0002
wherein U = SH, NH2 or OH, preferably NH2 or OH, more preferably OH; and p is an integer selected from 0-4, preferably 1-3, more preferably 1 or 2.
8. Saponin derivative according to any one of the claims 1-7, wherein n = 1 and m = 1, or n = 2 and m = 1, or n = 2 and m = 2, or n = 3 and m = 2, or n = 3 and m = 3; preferably wherein n = 2 and m = 2.
9. Saponin derivative according to any one of the claims 1-8, wherein R1 is selected from: H, GlcA-, Glc-, Gal-, Rha-(1→2)-Ara-, Gal-(1→2)-[Xyl-(1→3)]-GlcA-, Glc-(1→2)-[Glc-(1→4)]-GlcA-, Glc-(1→2)-Ara-(1→3)-[Gal-(1→2)]-GlcA-, Xyl-(1→2)-Ara-(1→3)-[Gal-(1→2)]-GlcA-, Glc-(1→3)-Gal-(1→2)-[Xyl-(1→3)]-Glc-(1→4)-Gal-, Rha-(1→2)-Gal-(1→3)-[Glc-(1→2)]-GlcA-, Ara-(1→4)-Rha-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Rha-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Ara-(1→4)-Rha-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Ara-(1→4)-Rha-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, Ara-(1→4)-Fuc-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Glc-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Gal-(1→2)-Rha-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Glc-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Rha-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, Xyl-(1→4)-Fuc-(1→2)-Gal-(1→2)-Fuc-(1→2)-GlcA-, and derivatives thereof, and R2 is selected from: H, Glc-, Gal-, Rha-(1→2)-[Xyl-(1→4)]-Rha-, Rha-(1→2)-[Ara-(1→3)-Xyl-(1→4)]-Rha-, Ara-, Xyl-, Xyl-(1→4)-Rha-(1→2)-[R1-(→4)]-Fuc- wherein R1 is 4E-Methoxycinnamic acid, Xyl-(1→4)-Rha-(1→2)-[R2-(→4)]-Fuc- wherein R2 is 4Z-Methoxycinnamic acid, Xyl-(1→4)-[Gal-(1→3)]-Rha-(1→2)-4-OAc-Fuc-, Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-3,4-di-OAc-Fuc-, Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R6-(→4)]-3-OAc-Fuc- wherein R6 is 4E-Methoxycinnamic acid, Glc-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-4-OAc-Fuc-, Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-4-OAc-Fuc-, (Ara- or Xyl-)(1→3)-(Ara- or Xyl-)(1→4)-(Rha- or Fuc-)(1→2)-[4-OAc-(Rha- or Fuc-)(1→4)]-(Rha- or Fuc-), Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Qui-(1→4)]-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-Fuc-, Xyl-(1→4)-[Gal-(1→3)]-Rha-(1→2)-Fuc-, Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-Fuc-, Ara/Xyl-(1→4)-Rha/Fuc-(1→4)-[Glc/Gal-(1→2)]-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R7-(→4)]-Fuc- wherein R7 is 5-O-[5-O-Ara/Api-3,5- dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R8-(→4)]-Fuc- wherein R8 is 5-O-[5-O-Ara/Api-3,5-dihydroxy-6- methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Rha-(1→3)]-4-OAc-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[Rha-(1→3)]-4-OAc-Fuc-, 6-OAc-Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3-OAc-Rha-(1→3)]-Fuc-, Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3-OAc--Rha-(1→3)]-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Qui-(1→4)]-Fuc-, Glc-(1→3)-[Xyl-(1→4)]-Rha-(1→2)-[Qui-(1→4)]-Fuc-, Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3,4-di-OAc-Qui-(1→4)]-Fuc-, Glc-(1→3)-[Xyl-(1→4)]-Rha-(1→2)-Fuc-, 6-OAc-Glc-(1→3)-[Xyl-(1→4)]-Rha-(1→2)-Fuc-, Glc-(1→3)-[Xyl-(1→3)-Xyl-(1→4)]-Rha-(1→2)-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[Rha-(1→3)]-4OAc-Fuc-, Api-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[Rha-(1→3)]-4OAc-Fuc-, Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R9-(→4)]-Fuc- wherein R9 is 5-O-[5-O-Rha- (1→2)-Ara/Api-3,5-dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R10-(→4)]-Fuc- wherein R10 is 5-O-[5-O- Ara/Api-3,5-dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api/Xyl-(1→3)-Xyl-(1→4)-[Glc-(1→3)]-Rha-(1→2)-[R11-(→4)]-Fuc- wherein R11 is 5-O-[5-O- Ara/Api-3,5-dihydroxy-6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R12-(→4)]-Fuc- wherein R12 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R13-(→4)]-Fuc- wherein R13 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R14-(→3)]-Fuc- wherein R14 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid), Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R15-(→3)]-Fuc- wherein R15 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid) Glc-(1→3)-[Glc-(1→6)]-Gal-, and derivatives thereof.
10. Saponin derivative according to any one of the claims 1-9, wherein R1 is Gal-(1→2)-[Xyl-(1→3)]-GlcA-; and R2 is selected from: Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl-(1→3)-4-OAc-Qui-(1→4)]-Fuc-, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[3,4-di-OAc-Qui-(1→4)]-Fuc-, Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R12-(→4)]-Fuc- wherein R12 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R13-(→4)]-Fuc- wherein R13 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, Api-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R14-(→3)]-Fuc- wherein R14 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, and Xyl-(1→3)-Xyl-(1→4)-Rha-(1→2)-[R15-(→3)]-Fuc- wherein R15 is 5-O-[5-O-Ara/Api-3,5-dihydroxy- 6-methyl-octanoyl]-3,5-dihydroxy-6-methyl-octanoic acid, preferably, R1 is Gal-(1→2)-[Xyl-(1→3)]-GlcA- and R2 is Glc-(1→3)-Xyl-(1→4)-Rha-(1→2)-[Xyl- (1→3)-4-OAc-Qui-(1→4)]-Fuc-.
11. Saponin derivative of any one of the claims 1-10, wherein the saponin on which the saponin derivative is based is any one or more of: a) saponin selected from any one or more of list A: - Quillaja saponaria saponin mixture, or a saponin isolated from Quillaja saponaria, for example Quil-A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; - Gypsophila elegans saponin mixture, or a saponin isolated from Gypsophila elegans; - Saponinum album saponin mixture, or a saponin isolated from Saponinum album; - Saponaria officinalis saponin mixture, or a saponin isolated from Saponaria officinalis; and - Quillaja bark saponin mixture, or a saponin isolated from Quillaja bark, for example Quil- A, QS-17-api, QS-17-xyl, QS-21, QS-21A, QS-21B, QS-7-xyl; or b) a saponin comprising a gypsogenin aglycone core structure, selected from list B: SA1641, gypsoside A, NP-017772, NP-017774, NP-017777, NP-017778, NP-018109, NP- 017888, NP-017889, NP-018108, SO1658 and Phytolaccagenin; or c) a saponin comprising a quillaic acid aglycone core structure, selected from list C: AG1856, AG1, AG2, Agrostemmoside E, GE1741, Gypsophila saponin 1 (Gyp1), NP- 017674, NP-017810, NP-003881, NP-017676, NP-017677, NP-017705, NP-017706, NP- 017773, NP-017775, SA1657, Saponarioside B, SO1542, SO1584, SO1674, SO1700, SO1730, SO1772, 10 SO1832, SO1861, SO1862, SO1904, QS-7, QS-7 api, QS-17, QS- 18, QS-21 A-apio, QS-21 A-xylo, QS-21 B-apio and QS-21 B-xylo; preferably, the saponin is any one or more of a saponin selected list B or C, more preferably, a saponin selected from list C.
12. Saponin derivative of any one of the claims 1-11, wherein the saponin is any one or more of AG1856, GE1741, a saponin isolated from Quillaja saponaria, Quil-A, QS-17, QS-21, QS-7, SA1641, a saponin isolated from Saponaria officinalis, Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; preferably wherein the saponin is any one or more of QS-21, SO1832, SO1861, SA1641 and GE1741; more preferably wherein the saponin is QS-21, SO1832 or SO1861; most preferably being SO1861.
13. Saponin derivative of any one of the claims 1-12, wherein the saponin is a saponin isolated from Saponaria officinalis, preferably wherein the saponin is any one or more of Saponarioside B, SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; more preferably wherein the saponin is any one or more of SO1542, SO1584, SO1658, SO1674, SO1700, SO1730, SO1772, SO1832, SO1861, SO1862 and SO1904; even more preferably wherein the saponin is any one or more of SO1832, SO1861 and SO1862; even more preferably wherein the saponin is SO1832 and SO1861; most preferably being SO1861.
14. Saponin derivative according to any one of the claims 1-13, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (IX)
Figure imgf000235_0001
wherein n and m each are an integer independently selected from 1, 2, or 3; o is an integer selected from 0-10, preferably 2-7, more preferably 4-6.
15. Saponin derivative according to any one of the claims 1-14, wherein the saponin derivative is according to molecule (KK):
Figure imgf000235_0002
, wherein
Figure imgf000235_0003
represents a saponin moiety according to formula (SM):
Figure imgf000236_0001
, wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide according to any one of the claims 1-14, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23 according to any one of the claims 1-14.
16. Saponin derivative according to any one of the claims 1-15, wherein the saponin derivative is according to formula (V), formula (VI), formula (VII) or formula (VIII)
Figure imgf000236_0002
Figure imgf000237_0001
Figure imgf000238_0001
(VIII), preferably wherein the saponin derivative is according to formula (V), formula (VII) or formula (VIII), more preferably wherein the saponin derivative is according to formula (V) or formula (VIII), most preferably according to formula (VIII).
17. Saponin derivative according to any one of the claims 1-13, wherein the saponin derivative is according to molecule (AA):
Figure imgf000238_0002
, wherein
Figure imgf000238_0003
represents a saponin moiety according to formula (SM):
Figure imgf000239_0001
, wherein R1 and R2 are independently selected from hydrogen, a monosaccharide, a linear oligosaccharide and a branched oligosaccharide according to any one of the claims 1-16, and wherein the saponin moiety according to formula (SM) is based on a saponin comprising an aldehyde group in position C-23 according to any one of the claims 1-16.
18. First pharmaceutical composition comprising the saponin derivative according to any one of the claims 1-17 and optionally a pharmaceutically acceptable excipient and/or diluent.
19. First pharmaceutical combination comprising: (a) the first pharmaceutical composition of claim 18; and (b) a second pharmaceutical composition comprising any one or more of: a conjugate of a cell- surface molecule binding-molecule and an effector moiety, an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-oligonucleotide conjugate and a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
20. Third pharmaceutical composition comprising the saponin derivative of any one of the claims 1-17 and further comprising any one or more of: a conjugate of a cell-surface molecule binding- molecule and an effector moiety, an antibody-effector moiety conjugate, a receptor-ligand – effector moiety conjugate, an antibody-toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-drug conjugate, a receptor-ligand – drug conjugate, an antibody-oligonucleotide conjugate and a receptor-ligand – oligonucleotide conjugate, and optionally comprising a pharmaceutically acceptable excipient and/or diluent.
21. First pharmaceutical combination comprising the second pharmaceutical composition of claim 19, or the third pharmaceutical composition of claim 20, wherein the second pharmaceutical composition or the third pharmaceutical composition comprises any one or more of an antibody- toxin conjugate, a receptor-ligand – toxin conjugate, an antibody-oligonucleotide conjugate or a receptor-ligand – oligonucleotide conjugate, wherein preferably the toxin is a protein toxin.
22. First pharmaceutical combination comprising the first pharmaceutical composition of claim 19 or 21, or the third pharmaceutical composition of claim 20 or 21, wherein the saponin derivative is any one or more of the saponin derivatives according to claim 16.
23. First pharmaceutical composition of claim 18, first pharmaceutical combination of any one of the claims 19, 21 and 22 or the third pharmaceutical composition of any one of the claims 20- 22, for use as a medicament.
24. First pharmaceutical composition of claim 18, first pharmaceutical combination of any one of the claims 19, 21 and 22 or the third pharmaceutical composition of any one of the claims 20- 22, for use in the treatment or prophylaxis of a cancer or an auto-immune disease.
25. In vitro or ex vivo method for transferring a molecule from outside a cell to inside said cell, preferably into the cytosol of said cell, comprising the steps of: a) providing a cell; b) providing the molecule for transferring from outside the cell into the cell provided in step a); c) providing a saponin derivative according to any one of the claims 1-17; d) contacting the cell of step a) in vitro or ex vivo with the molecule of step b) and the saponin derivative of step c), therewith establishing the transfer of the molecule from outside the cell into said cell.
26. Saponin conjugate based on a saponin derivative according to any one of the claims 1-17, wherein the aldehyde group is transformed into a semicarbazone functional group according to formula (IX)
Figure imgf000240_0001
wherein n and m each are an integer independently selected from 1, 2, or 3; o is an integer selected from 0-10, preferably 2-7, more preferably 4-6; and wherein the maleimide functional group is further transformed into a thioether bond through reaction with a first proteinaceous molecule (‘proteinaceous molecule 1’) comprising a thiol functional group according to formula (X)
Figure imgf000241_0001
(X).
27. Saponin conjugate according to claim 26, wherein the saponin conjugate is according to formula (XI)
Figure imgf000241_0002
wherein R1 and R2 are as defined in any one of claims 1-10; n and m each are an integer independently selected from 1, 2 or 3; and o is an integer selected from 0-10, preferably 2-7, more preferably 4-6.
28. Saponin conjugate according to claim 26 or 27, wherein n = 1 and m = 1, or n = 2 and m = 1, or n = 2 and m = 2, or n = 3 and m = 2, or n = 3 and m = 3; preferably wherein n = 2 and m = 2.
29. Saponin conjugate according to any one of the claims 26-28, wherein the saponin conjugate is according to formula (XII)
Figure imgf000242_0001
30. Saponin conjugate according to any one of the claims 26-29, wherein the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule.
31. Saponin conjugate according to any one of the claims 26-30, wherein the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule, wherein said first binding site is or comprises any one or more of: an amino acid, a peptide, a protein, an antibody or a binding derivative or binding fragment or binding domain thereof such as a F(ab')2 fragment, Fab' fragment, Fab fragment, scFv, dsFv, scFv-Fc, reduced IgG (rIgG), minibody, diabody, triabody, tetrabody, Fc fusion protein, nanobody, variable V domain, a single-domain antibody (sdAb), preferably a VHH, for example camelid VH, or a ligand for a cell-surface molecule such as a receptor such as EGF or a cytokine.
32. Saponin conjugate according to any one of the claims 26-31, wherein the proteinaceous molecule 1 comprises a cell-surface molecule binding-molecule comprising a first binding site for binding to a first epitope of a first cell-surface molecule, wherein said first binding site is or comprises any one or more of: a single-domain antibody (sdAb), preferably a VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VHH domain such as derived from a heavy-chain only antibody (HCAb) such as from Camelidae origin or Ig-NAR origin such as a variable heavy chain new antigen receptor (VNAR) domain, preferably the HCAb is from Camelidae origin, preferably the sdAb is a VHH domain derived from an HCAb from Camelidae origin (camelid VH) such as derived from an HCAb from camel, lama, alpaca, dromedary, vicuna, guanaco and Bactrian camel.
33. Saponin conjugate according to any one of the claims 30-32, wherein the first epitope of the first cell-surface molecule is a tumor-cell specific first epitope of a first tumor-cell surface molecule, more preferably a tumor-cell specific first epitope of a first tumor-cell surface receptor specifically present on a tumor cell.
34. Saponin conjugate according to any one of the claims 26-33, wherein the proteinaceous molecule 1 comprises a covalently bound effector moiety.
35. Saponin conjugate according to claim 34, wherein the effector moiety is an oligonucleotide, preferably an oligonucleotide defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt.
36. Saponin derivative according to any one of the claims 1-17 or saponin conjugate according to any one of the claims 26-34, wherein the semicarbazone functional group
Figure imgf000243_0001
is hydrolysable under acidic conditions, preferably at pH 4.0 – 6.5, wherein hydrolysis of said semicarbazone functional group provides the aldehyde group on the aglycone core structure of the saponin on which the saponin derivative is based.
37. Saponin derivative according to any one of the claims 1-17 or saponin conjugate according to any one of the claims 26-36, wherein the semicarbazone functional group is subject to hydrolysis in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ≤ 5.5.
38. Second pharmaceutical combination comprising: (a) a fourth pharmaceutical composition comprising the saponin conjugate of any one of the claims 26-33 or 36-37 and optionally a pharmaceutically acceptable excipient and/or diluent; and (b) a fifth pharmaceutical composition comprising a conjugate comprising a cell- surface molecule binding-molecule, such as a second proteinaceous molecule (‘proteinaceous molecule 2’), and an effector moiety, wherein the proteinaceous molecule 2 is the same or different from the proteinaceous molecule 1 present in the saponin conjugate, and if the proteinaceous molecule 2 is different from the proteinaceous molecule 1, the proteinaceous molecule 2 comprising a second binding site for binding to a second epitope of a second cell-surface molecule, wherein the second cell-surface molecule is the same as or different from the first cell surface molecule, and if the second cell-surface molecule is different from the first cell surface molecule, the second cell-surface molecule and the first cell surface molecule are preferably present on the same cell, the fifth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent.
39. Second pharmaceutical combination of claim 38, comprising: (a) the fourth pharmaceutical composition of claim 38 comprising the saponin conjugate of any one of the claims 26-33 or 36-37, wherein the first epitope on the first cell-surface molecule is a tumor-cell specific first epitope on a first tumor cell-specific surface molecule, preferably a tumor-cell specific first epitope on a first cell-surface receptor specifically present on a tumor cell; and (b) the fifth pharmaceutical composition of claim 38, wherein the second cell-surface molecule is a second tumor cell-specific surface molecule which is the same or different from the first tumor cell-specific surface molecule, preferably a second cell-surface receptor specifically present on a tumor cell which is the same or different from the first cell-surface receptor specifically present on said tumor cell, and wherein the second epitope is a tumor- cell specific second epitope, wherein the first epitope and the second epitope, which is the same as or different from the first epitope, are exposed at the same cell.
40. Third pharmaceutical combination, comprising: (a) the fourth pharmaceutical composition of claim 38 or 39 comprising the saponin conjugate according to of any one of the claims 26-33 or 36-37 and comprising the first binding site for binding to the first epitope on the first cell-surface molecule, the fourth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent; and (b) a sixth pharmaceutical composition comprising a conjugate comprising a cell- surface molecule binding-molecule, such as a third proteinaceous molecule (‘proteinaceous molecule 3’), and an effector moiety, wherein the proteinaceous molecule 3 comprises the first binding site for binding to the first epitope on the cell- surface molecule of (a), the sixth pharmaceutical composition optionally further comprising a pharmaceutically acceptable excipient and/or diluent, wherein the first binding site of the proteinaceous molecule 1 and the first binding site of the proteinaceous molecule 3 are the same, and wherein the first cell-surface molecule and the first epitope on the first cell-surface molecule, to which the proteinaceous molecule 1 can bind, and the first cell-surface molecule and the first epitope on the first cell-surface molecule, to which the proteinaceous molecule 3 can bind, are the same.
41. Third pharmaceutical combination, comprising: (a) the fourth pharmaceutical composition of claim 40 and (b) the sixth pharmaceutical composition of claim 40, wherein the first cell-surface molecule is expressed on a tumor cell surface, and preferably the first cell-surface molecule is a tumor cell-specific surface molecule, and wherein preferably the first epitope is a first tumor-cell specific epitope.
42. Second pharmaceutical combination according to claim 38 or 39 or third pharmaceutical combination according to claim 40 or 41, wherein the second binding site of the proteinaceous molecule 2 and/or the third binding site of the proteinaceous molecule 3 comprises or consists of an antibody, or a derivative or fragment thereof such as a Fab or an scFv, a ligand, a single- domain antibody (sdAb), preferably VH domain derived from a heavy chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VL domain derived from a light chain of an antibody, preferably of immunoglobulin G origin, preferably of human origin, a VHH domain such as derived from a heavy-chain only antibody (HCAb) such as from Camelidae origin or Ig-NAR origin such as a variable heavy chain new antigen receptor (VNAR) domain, preferably the HCAb is from Camelidae origin, preferably the sdAb is a VHH domain derived from an HCAb from Camelidae origin (camelid VH) such as derived from an HCAb from camel, lama, alpaca, dromedary, vicuna, guanaco and Bactrian camel.
43. A seventh pharmaceutical composition comprising: (a) the saponin conjugate of any one of the claims 26-33 or 36-37; and (b) the conjugate comprising proteinaceous molecule 2 and an effector moiety of claim 38 or 39, or the conjugate comprising proteinaceous molecule 3 and an effector moiety of claim 40, and optionally further comprising a pharmaceutically acceptable excipient and/or diluent.
44. The second pharmaceutical combination of any one the claims 38, 39 or 42 or third pharmaceutical combination of any one the claims 40-42, or the seventh pharmaceutical composition of claim 43, for use as a medicament.
45. The second pharmaceutical combination of any one the claims 38, 39 or 42 or third pharmaceutical combination of any one the claims 40-42, or the seventh pharmaceutical composition of claim 43, for use in the treatment or prevention of a cancer or of an autoimmune disease such as rheumatoid arthritis.
46. An eighth pharmaceutical composition comprising the saponin conjugate of claim 34 or 35 and optionally a pharmaceutically acceptable excipient and/or pharmaceutically acceptable diluent.
47. The eighth pharmaceutical composition of claim 46 or the saponin conjugate of claim 34 or 35 for use as a medicament.
48. The eighth pharmaceutical composition of claim 46 or the saponin conjugate of claim 34 or 35 for use in the treatment of a cardiovascular disease or hypercholesterolemia or for use in a method for lowering LDL-cholesterol in the blood of a subject, wherein the effector moiety is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, silencing gene apolipoprotein B (apoB), wherein preferably the oligonucleotide is any one of a BNA, a xeno nucleic acid, an siRNA, an antisense oligonucleotide.
49. Saponin derivative based on the saponin derivative according to molecule (AA) of claim 17, and according to molecule (BB):
Figure imgf000246_0001
, which molecule (BB) is the covalent conjugation product obtained by the covalent conjugation of the saponin derivative according to molecule (AA) of claim 17 with the tri-functional linker according to formula (XXI):
Figure imgf000247_0001
(XXI).
50. Saponin conjugate based on the saponin derivative according to molecule (AA) of claim 17, and according to molecule (CC):
Figure imgf000247_0002
, which molecule (CC) is the covalent conjugation product obtained by the covalent conjugation of the tri-functional linker according to formula (XXI) with the saponin derivative according to molecule (AA) of claim 17 and with GalNAc conjugate according to molecule (FF):
Figure imgf000248_0001
, wherein
Figure imgf000248_0002
represents the tri-GalNAc conjugate according to molecule (DD1) or according to molecule (DD2):
Figure imgf000249_0001
ĨDD1), wherein y1, y2 and y3 each are an integer independently selected from 0-20, preferably 1-15, more preferably 2-12, even more preferably 2-10, even more preferably 2-8, most preferably 2 and 3, and preferably y1, y2 and y3 are the same, and y4 is an integer selected from 1-100, preferably 2-80, more preferably 3-70, even more preferably 4-60, even more preferably 4-50, even more preferably 4-40, even more preferably 4-30, even more preferably 4-20, even more preferably 4-6, most preferably 4-5, such as 4;
Figure imgf000250_0001
(DD2), wherein x1, x2 and x3 each are an integer independently selected from 0-20, preferably 1-15, more preferably 2-12, even more preferably 2-10, even more preferably 2-8, most preferably 2 and 3, and preferably x1, x2 and x3 are the same, and x4 is an integer selected from 1-50, preferably 2-40, more preferably 3-30, even more preferably 4-20, even more preferably 5-15, most preferably 8- 12, such as 9, and preferably represents the tri-GalNAc conjugate according to molecule (DD3) or according to molecule (DD4):
Figure imgf000251_0001
(DD4).
51. Saponin conjugate based on the saponin derivative according to molecule (AA) of claim 17, and according to molecule (EE):
Figure imgf000252_0001
, which molecule (EE) is the covalent conjugation product obtained by the covalent conjugation of the tri-functional linker according to formula (XXI) with the saponin derivative according to molecule (AA) of claim 17 and with GalNAc conjugate according to molecule (FF) of claim 50 and with the oligonucleotide provided with a linker according to molecule (GG):
Figure imgf000252_0002
, wherein the molecule (GG) represents the conjugation product of the conjugation reaction between the linker (E)-1-(4-((2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)hexanoyl)hydrazineylidene)methyl)benzamido)-N-(4-(6-methyl-1,2,4,5-tetrazin-3-yl)benzyl)- 3,6,9,12-tetraoxapentadecan-15-amide and the oligonucleotide-linker molecule according to molecule (HH):
Figure imgf000253_0001
52. Saponin derivative based on the saponin derivative according to molecule (KK) of claim 15, and according to molecule (JJ):
Figure imgf000253_0002
which molecule (JJ) is the conjugate product of conjugation of N,N'-((9S,19S)-14-(6- aminohexanoyl)-1-mercapto-9-(3-mercaptopropanamido)-3,10,18-trioxo-4,11,14,17- tetraazatricosane-19,23-diyl)bis(3-mercaptopropanamide first with the saponin derivative according to molecule (KK), of claim 15, and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido-3,6,9,12- tetraoxapentadecan-15-oate.
53. Saponin conjugate based on the saponin derivative according to molecule (KK) of claim 15, and according to molecule (LL):
Figure imgf000254_0001
, which molecule (LL) is the covalent conjugation product obtained by the covalent conjugation of the molecule (JJ) of claim 52 with the conjugate of the tri-functional linker and GalNAc according to molecule (MM):
Figure imgf000255_0001
, wherein molecule (MM) is the conjugate of the tri-functional linker according to formula (XXI) and the GalNAc conjugate according to molecule (NN):
Figure imgf000255_0002
, wherein
Figure imgf000256_0001
represents the tri-GalNAc conjugate according to molecule (DD1) or molecule (DD2), preferably molecule (DD3) or molecule (DD4), more preferably molecule (DD3) of claim 50.
54. Saponin conjugate based on the saponin derivative according to molecule (KK) of claim 15, and according to molecule (PP): ed oecunog o
Figure imgf000256_0002
, which molecule (PP) is the covalent conjugation product obtained by the covalent conjugation of the molecule (LL) of claim 53 with the oligonucleotide provided with a linker according to molecule (GG) of claim 51.
55. Saponin derivative based on the saponin derivative according to molecule (KK) of claim 15, and according to molecule (QQ):
Figure imgf000257_0001
which molecule (QQ) is the conjugate product of conjugation of (2S)-N-[(1S)-1-{[2-(6-amino-N-{2- [(2S)-2,6-bis[(2S)-2,6-bis(3- sulfanylpropanamido)hexanamido]hexanamido]ethyl}hexanamido)ethyl]carbamoyl}-5-[(2S)-2,6- bis(3-sulfanylpropanamido)hexanamido]pentyl]-2,6-bis(3-sulfanylpropanamido)hexanamide formate first with saponin derivative according to molecule (KK) of claim 15 and subsequently with 2,5-dioxopyrrolidin-1-yl 1-azido-3,6,9,12-tetraoxapentadecan-15-oate.
56. Saponin conjugate based on the saponin derivative according to molecule (KK) of claim 15, and according to molecule (RR):
Figure imgf000258_0001
, which molecule (RR) is the covalent conjugation product obtained by the covalent conjugation of the molecule (QQ) of claim 55 with the conjugate of the tri-functional linker and GalNAc according to molecule (MM) of claim 53.
57. Saponin conjugate based on the saponin derivative according to molecule (KK) of claim 15, and according to molecule (SS):
Figure imgf000259_0001
, which molecule (SS) is the covalent conjugation product obtained by the covalent conjugation of the molecule (RR) of claim 56 with the oligonucleotide provided with a linker according to molecule (GG) of claim 51.
58. Saponin derivative according to any one of the claims 49, 52 and 55 or saponin conjugate according to any one of the claims 50, 51, 53, 54, 56 and 57, wherein the saponin derivative or the saponin conjugate is based on a saponin according to any one of the claims 1-17.
59. Saponin derivative according to any one of the claims 49, 52, 55 and 58 or saponin conjugate according to any one of the claims 50, 51, 53, 54 and 56-58, wherein the saponin derivative or the saponin conjugate is based on a saponin selected from SO1861, SO1832 and QS-21, preferably SO1861 and SO1832, more preferably SO1861.
60. Saponin derivative according to any one of the claims 49, 52, 55, 58 and 59 or saponin conjugate according to any one of the claims 50, 51, 53, 54 and 56-59, wherein the semicarbazone functional group is subject to hydrolysis in vivo under acidic conditions as present in endosomes and/or lysosomes of mammalian cells, preferably human cells, preferably at pH 4.0 – 6.5, and more preferably at pH ≤ 5.5.
61. Saponin conjugate of any one of the claims 51, 54 and 57, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, wherein the oligonucleotide is any one of a BNA, a xeno nucleic acid, an siRNA, an antisense oligonucleotide, and/or wherein the oligonucleotide is defined as a nucleic acid no longer than 150 nt, preferably wherein the oligonucleotide has a size of 5 – 150 nt, more preferably being 8 – 100 nt, most preferably being 10 – 50 nt.
62. Saponin conjugate of any one of the claims 51, 54, 57 and 61, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, wherein the oligonucleotide is selected from any one or more of a(n): short interfering RNA (siRNA), short hairpin RNA (shRNA), anti-hairpin- shaped microRNA (miRNA), single-stranded RNA, aptamer RNA, double-stranded RNA (dsRNA), anti-microRNA (anti-miRNA, anti-miR), antisense oligonucleotide (ASO), DNA, antisense DNA, locked nucleic acid (LNA), bridged nucleic acid (BNA), 2’-O,4’-aminoethylene bridged nucleic acid (BNANC), BNA-based siRNA, and BNA-based antisense oligonucleotide (BNA-AON).
63. Saponin conjugate of any one of the claims 51, 54, 57, 61 and 62, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, wherein the oligonucleotide is selected from any one or more of a(n): anti-miRNA, a BNA-AON or an siRNA, such as BNA-based siRNA, selected from chemically modified siRNA, metabolically stable siRNA and chemically modified, metabolically stable siRNA.
64. Saponin conjugate of any one of the claims 51, 54, 57 and 61-63, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, silencing any one of genes: apolipoprotein B (apoB), HSP27, transthyretin (TTR), proprotein convertase subtilisin/kexin type 9 (PCSK9), TMPRSS6, delta-aminolevulinate synthase 1 (ALAS1), anti-thrombin 3 (AT3), glycolate oxidase (GO), complement component C5 (CC5), X gene of hepatitis B virus (HBV), S gene of HBV, alpha-1 antitrypsin (AAT), miR- 122, hepatitis B virus HbsAg, LDHA, CEBPA and lactate dehydrogenase (LDH), and/or is an oligonucleotide capable of, for example when present inside a mammalian cell, targeting an aberrant miRNA.
65. Saponin conjugate of any one of the claims 51, 54, 57 and 61-64, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, silencing any one of genes: apolipoprotein B (apoB) and HSP27.
66. Saponin conjugate of any one of the claims 51, 54, 57 and 61-65, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, targeting an mRNA involved in expression of any one of proteins: apoB, HSP27, TTR, PCSK9, TMPRSS6, ALAS1, AT3, GO, CC5, expression product of X gene of HBV, expression product of S gene of HBV, AAT, miR-122, hepatitis B virus HbsAg, LDHA, CEBPA and LDH, or is capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, antagonizing or restoring an miRNA function such as inhibiting an oncogenic miRNA (onco-miR) or suppression of expression of an onco-miR.
67. Saponin conjugate of any one of the claims 51, 54, 57 and 61-66, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, targeting an mRNA involved in expression of any one of proteins: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AAT, miR-122, hepatitis B virus HbsAg, LDHA and CEBPA.
68. Saponin conjugate of any one of the claims 51, 54, 57 and 61-67, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, wherein the oligonucleotide is an oligonucleotide capable of, for example when present inside a mammalian cell and preferably when present inside a human cell, targeting an mRNA involved in expression of any one of proteins: apoB and HSP27.
69. Ninth pharmaceutical composition comprising the saponin conjugate of any one of the claims 51, 54, 57 and 61-68, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, and optionally a pharmaceutically acceptable excipient and/or optionally a pharmaceutically acceptable diluent.
70. Ninth pharmaceutical composition of claim 69 or saponin conjugate of any one of the claims 51, 54, 57 and 61-68, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, for use as a medicament.
71. Ninth pharmaceutical composition of claim 69 or saponin conjugate of any one of the claims 51, 54, 57 and 61-68, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, for use in the treatment or prophylaxis of a disease or health problem in which an expression product is involved of any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AT3, GO, CC5, X gene of HBV, S gene of HBV, AAT, miR-122, hepatitis B virus HbsAg, LDHA, CEBPA and LDH, and/or for use in the treatment or prophylaxis of a disease or health problem which involves any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AT3, GO, CC5, X gene of HBV, S gene of HBV, AAT, miR-122, hepatitis B virus HbsAg, LDHA, CEBPA and LDH.
72. Ninth pharmaceutical composition of claim 69 or saponin conjugate of any one of the claims 51, 54, 57 and 61-68, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, for use in the treatment or prophylaxis of a disease or health problem in which an expression product is involved of any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AAT, miR-122, hepatitis B virus HbsAg, LDHA and CEBPA, and/or for use in the treatment or prophylaxis of a disease or health problem which involves any one or more of genes: HSP27, apoB, TTR, PCSK9, TMPRSS6, ALAS1, AAT, miR-122, hepatitis B virus HbsAg, LDHA and CEBPA.
73. Ninth pharmaceutical composition of claim 69 or saponin conjugate of any one of the claims 51, 54, 57 and 61-68, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, for use according to claim 71 or 72, wherein said use is in the treatment or prophylaxis of a disease or health problem in which an expression product is involved of any one or more of genes: HSP27 and apoB, preferably apoB, and/or for use in the treatment or prophylaxis of a disease or health problem which involves any one or more of genes: HSP27 and apoB, preferably apoB.
74. Ninth pharmaceutical composition or saponin conjugate for use of any one of the claims 71-73, for use in the treatment or prophylaxis of a cancer, an infectious disease, a viral infection, hypercholesterolemia, cardiovascular disease, primary hyperoxaluria, haemophilia A, haemophilia B, AAT related liver disease, acute hepatic porphyria, TTR-mediated amyloidosis, hereditary TTR amyloidosis (hATTR), complement-mediated disease, hepatitis B infection, hepatitis C infection, α1-antitrypsin deficiency, β-thalassaemia, or an auto-immune disease.
75. Ninth pharmaceutical composition or saponin conjugate for use of any one of the claims 71-74, wherein said use is in the treatment or prophylaxis of a cancer such as endometrial carcinoma, breast cancer, lung cancer or hepatocellular carcinoma, and/or a cardiovascular disease such as hypercholesterolemia, preferably hypercholesterolemia.
76. Ninth pharmaceutical composition of claim 69 or saponin conjugate of any one of the claims 51, 54, 57 and 61-68, and claims 58-60 in so far dependent on any one of claims 51, 54 and 57, for use in the lowering of LDL-cholesterol in a subject.
77. The saponin derivative of any one of the claims 1-17, 36, 37, 49, 52, 55 and 58-60, or the saponin conjugate of any one of the claims 36, 37, 50, 51, 53, 54 and 56-68, wherein the saponin on which the saponin derivative is based or on which the saponin conjugate is based, is isolated from a plant.
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