CN110575548A

CN110575548A - Antibody-drug conjugate targeting CD73 and preparation method and application thereof

Info

Publication number: CN110575548A
Application number: CN201810582699.5A
Authority: CN
Inventors: 沈竞康; 孟韬; 马兰萍; 王昕�; 陈驎; 杜志彦; 于霆; 张永良
Original assignee: Shanghai Institute of Materia Medica of CAS
Current assignee: Shanghai Institute of Materia Medica of CAS
Priority date: 2018-06-07
Filing date: 2018-06-07
Publication date: 2019-12-17

Abstract

The invention describes an anti-CD 73 antibody drug conjugate, which is used for coupling a strong cytotoxic active substance and a biological macromolecule through a novel disubstituted maleimide linker. The linker can selectively act simultaneously with disulfide chains, thereby greatly improving the material uniformity of the conjugate. The conjugate prepared by the linker of the invention has high inhibitory activity on cell strains expressing CD73 antigen. In addition, the invention also provides a preparation method and application of the conjugate.

Description

Antibody-drug conjugate targeting CD73 and preparation method and application thereof

Technical Field

The invention relates to the field of medicines, in particular to an antibody-drug conjugate targeting CD73, and a preparation method and application thereof.

Background

Cluster of differentiation 73(CD73) (also known as extracellular-5' -nucleotidase) is a surface glycoprotein anchored to the outside of the cell membrane by Glycosylphosphatidylinositol (GPI). Not only participate in the salvage synthesis pathway of purine nucleotide and generate adenosine to interact with adenosine receptor, but also be an important immune signal molecule to conduct transmembrane signal transduction and cell adhesion. It catalyzes the hydrolysis of the phosphate ester bond of 5' -ribonucleotides and deoxyribonucleotides to yield the corresponding ribonucleotides and deoxyribonucleosides and nucleic acids.

CD73 has been reported to be expressed on a number of different cancers, including colorectal, pancreatic, bladder, leukemia, lymphoma, glioma, glioblastoma, melanoma, ovarian, thyroid, esophageal, prostate, and breast cancers. In addition, CD73 expression in cancer is associated with increased proliferation, migration, neovascularization, invasiveness, metastasis and shorter patient survival. CD73 activity has also been proposed as a prognostic marker in papillary thyroid carcinomas. MedImmune reported a monoclonal antibody MEDI-9447 targeting CD73, which is currently targeted to CD73 in clinical studies. The antibody inhibits recombinant and cellular CD73 ectonucletidase activity and syngeneic tumor growth in a CT26 mouse model of colon cancer. Adenosine (adenosine) production was targeted extracellularly by CD73, reducing the immunosuppressive effects of adenosine (WO2016075176a 1; oncoimmunogy, 2016,5(8), e 1208875).

As mentioned above, CD73 plays an important role in the development of tumorigenesis. In addition to being effective against immunosuppression, the inventors found that CD73 is aberrantly expressed in tumor tissues compared to normal tissues, and that antibodies targeting CD73 can be rapidly internalized in large amounts compared to other targets, and thus CD73 may be a more preferred target for antibody-drug conjugate (ADC) development. However, there is currently a lack of highly specific antibody drug conjugates against human CD 73.

The antibody-drug conjugate utilizes the characteristic that a monoclonal antibody specifically recognizes a specific antigen on the surface of a tumor cell, thereby realizing the accurate delivery of an antitumor drug (such as a cytotoxic agent or a cytostatic agent, a small-molecule chemotherapeutic drug and the like) to a tumor target cell, the accumulation and release in cells and achieving the purpose of accurately killing tumors. ADC is also considered to be the most potential antitumor drug due to proper molecular weight, high stability, strong targeting property and small toxic and side effects. However, the successful development of ADC also has a plurality of problems which need to be considered and solved, such as specific identification of lesion sites by antibodies, low immune sensitization and capability of efficiently and rapidly generating endocytosis; antibody-drug linkers, which are highly stable in blood and specifically activated in target cells and efficiently release small molecule drugs (which would otherwise have unacceptable levels of toxicity to normal cells); the coupled small molecule drug has strong cell killing ability and the like.

Antibody drug conjugates generally consist of three parts: an antibody or antibody-like ligand, a small molecule drug, and a linker coupling the ligand to the drug. In the structure of antibody drug conjugates currently in clinical trials, highly active cytotoxic drugs are usually attached via a linker to lysine residues on the surface of the ligand, or cysteine residues in the hinge region of the antibody (reduced by the interchain disulfide moiety), with an optimal drug/ligand ratio (DAR) of 2-4. The large number of lysine residues (over 80) on the antibody surface and the non-selectivity of the conjugation reaction lead to uncertainty in the number and position of conjugation, which in turn leads to heterogeneity of the resulting antibody drug conjugates. For example, the DAR value distribution for T-DM1 (average DAR value of 3.5) is 0-8. Similarly, although there are only four pairs of interchain disulfide bonds in the hinge region of an antibody, partial reduction of interchain disulfide bonds is required to achieve the optimum average DAR value (2-4). Since the existing reducing agents (DTT, TCEP, etc.) do not selectively reduce interchain disulfide bonds, the resulting conjugates are also not homogeneous products, consisting of a plurality of components, whose main components have DAR values of 0,2,4,6,8, and the components corresponding to each specific DAR value are present as isomers due to differences in the attachment sites. Heterogeneity of antibody drug conjugate products can lead to heterogeneity of pharmacokinetic properties, potency, and toxicity among the component parts. For example, components with higher DAR values are cleared more rapidly in vivo and result in higher toxicity.

Aiming at the problems of the coupling technology, the aim of fixed-point coupling of the existing antibody is fulfilled by a simple chemical method, so that a large amount of manpower, material resources and financial resources are saved, and the method is more attractive. Most methods in the prior art have the problems of long synthetic route of a coupling reagent, poor chemical stability of the coupling reagent, disordered electrophoresis patterns of an antibody conjugate, prompting that side reactions may exist in the coupling process, and the problems of sulfydryl exchange (reverse Michael addition reaction) in the in vivo circulation process and the like in the existing scheme. Therefore, there is an urgent need in the art to provide efficient, simple, and practical chemical conjugation methods for the research and development of antibody-drug conjugates targeting CD 73.

Disclosure of Invention

The invention aims to provide an antibody-drug conjugate targeting CD 73.

The invention also provides a pharmaceutical application of the CD 73-targeted antibody-drug conjugate, and an effect of the antibody-drug conjugate in tumor inhibition or prevention.

The invention also provides methods of treating mammalian cells or associated pathological conditions using the CD 73-targeted antibody-drug conjugates.

The invention provides a coupling method, which couples toxin small molecules to a targeting CD73 antibody through a specific connector, and greatly improves the killing power of the antibody to tumor cells on the basis of not changing the affinity of the antibody.

In a first aspect of the present invention, there is provided a closed or open-loop maleimide-based antibody-drug conjugate, said conjugate having a structure represented by formula Ia and/or Ib;

Wherein the content of the first and second substances,

Ar' is selected from the group consisting of: substituted or unsubstituted C6-C10 aryl, substituted or unsubstituted 5-12 membered heteroaryl, substituted or unsubstituted C6-C10 arylene, substituted or unsubstituted 5-12 membered heteroarylene;

L₁is-O (CH) attached to an Ar' group₂CH₂O)_n-, where n is selected from any integer from 1 to 20, preferably from any integer from 1 to 10;

L₂Is a chemical bond or an AA-PAB structure; wherein AA is dipeptide or tripeptide or tetrapeptide fragment (i.e. polypeptide fragment consisting of 2-4 amino acids), and PAB is p-aminobenzyl carbamoyl;

CTD is bonded to L through an amide bond₂The cytotoxic small molecule drug of (a) and/or the drug for treating autoimmune diseases and anti-inflammation;

m is 1.0-5.0, preferably 3.0-4.2; more preferably 3.5 to 4.5; still more preferably 3.8 to 4.2, still more preferably 3.9 to 4.1, most preferably 4.0;

The antibody (Ab) is an antibody or antibody fragment that targets CD 73.

In another preferred embodiment, the formula Ib is a product obtained by ring-opening of N-phenylmaleimide in the formula Ia.

In another preferred embodiment, the conjugate is covalently linked to one or more drug components.

in another preferred embodiment, the conjugate comprises an antibody and a drug covalently coupled (e.g., by separate covalent attachment to a linker).

In another preferred embodiment, the closed or open-loop maleimide group is linked to a thiol group of an antibody hinge region after disulfide chain reduction.

In another preferred embodiment, the antibody-drug conjugate is obtained by reducing a disulfide bond in the hinge region of the antibody or antibody fragment to generate a pair of cysteine residues, and performing a substitution reaction between a thiol group in the cysteine residue and an aryl sulfide in the substituted maleimide linker-drug conjugate represented by formula Ic, thereby obtaining antibody-drug conjugates Ia and/or Ib.

In another preferred embodiment, said closed or open-ring maleimide group is attached to the antibody after complete reduction, i.e. 4 para-disulfide bonds of the hinge region are fully open, preferably m is from 3.8 to 4.2, more preferably from 3.9 to 4.1, most preferably 4.0.

In another preferred embodiment, the CD73 targeting antibody is selected from the group consisting of: monoclonal antibodies, bispecific antibodies, chimeric antibodies, humanized antibodies, antibody fragments (preferably antibody Fab fragments).

in another preferred embodiment, the antibody is an antibody capable of binding to CD 73.

In another preferred example, the antibody targeting CD73 is the clinically under study drug MEDI 9447.

In another preferred embodiment, Ar' is selected from the group consisting of: phenyl, halogenobenzene, C1-C4 alkylphenyl, C1-C4 alkoxyphenyl, 2-pyridyl, 2-pyrimidyl, 1-methylimidazol-2-yl,Wherein W is an amino group R attached to a carbonyl group¹，R¹Is selected from-NH₂、 Wherein: C1-C4 alkylphenyl is more preferably 4-methylphenyl; the C1-C4 alkoxyphenyl group is more preferably a 4-methoxyphenyl group.

In another preferred embodiment, Ar' is selected from substituted or unsubstituted phenylene or pyridyl, said substitution meaning that the hydrogen atoms on the group are substituted with one or more substituents selected from the group consisting of: halogen, C1-C4 alkyl, C1-C4 alkoxy, trifluoromethyl, nitrile group and amide group.

In another preferred embodiment, the AA is selected from the group consisting of: Val-Cit (valine-citrulline), Val-Ala (valine-alanine), Phe-Lys (phenylalanine-lysine), Ala-Ala-Asn (alanine-asparagine), D-Ala-Phe-Lys (alanine-phenylalanine-lysine D), Gly-Gly-Phe-Gly (glycine-phenylalanine-glycine).

In another preferred embodiment, the CTD is a cytotoxic small molecule drug selected from the group consisting of: tubulin inhibitors, topoisomerase inhibitors, DNA binding agents.

In another preferred embodiment, the tubulin inhibitor is selected from the group consisting of: maytansine (maytansine) derivatives, Monomethyl auristatin-E (MMAE), Monomethyl auristatin-F (MMAF), monomethyyl Dolastatin10 (MMAD), Tubulysin derivatives, Cryptophycin derivatives, Taltobulin, or combinations thereof.

In another preferred embodiment, the topoisomerase inhibitor is selected from the group consisting of: doxorubicin (Doxorubicin) metabolite PNU-159682 derivative, irinotecan (Exatecan, DX8951), irinotecan (CPT-11) metabolite SN38 derivative.

In another preferred embodiment, the DNA binding agent is selected from the group consisting of: a PBD-like derivative, a duocarmycin-like derivative, or a combination thereof.

In another preferred embodiment, the CTD has a molecular structure selected from the group consisting of D1-D14:

In another preferred embodiment, the antibody-drug conjugate (ADC) is selected from the group consisting of:

Conjugate ADC1 was structurally as follows:

Conjugate ADC2 was structurally as follows:

Conjugate ADC3 was structurally as follows:

Conjugate ADC4 was structurally as follows:

Conjugate ADC5 was structurally as follows:

Conjugate ADC6 was structurally as follows:

m is 3.5-4.5; preferably 3.8 to 4.2, more preferably 3.9 to 4.1, most preferably 4.0.

In another preferred embodiment, the antibody-drug conjugate (ADC) is selected from the group consisting of: MEDI 9447-vcMAE, MEDI9447-ADC1, MEDI9447-ADC2, MEDI9447-ADC3, MEDI9447-ADC4, MEDI9447-ADC5, and MEDI9447-ADC 6.

In a second aspect of the invention, there is provided a pharmaceutical composition comprising:

(i) An active ingredient which is an antibody drug conjugate according to any one of the first aspect of the invention or a pharmaceutically acceptable salt or solvate thereof or a combination thereof; and

(ii) A pharmaceutically acceptable diluent, carrier (vehicle) and/or excipient.

in a third aspect of the invention, there is provided the use of an antibody-drug conjugate according to any one of the first aspect of the invention for the preparation of a medicament for the treatment of a tumour, wherein the tumour is a CD73 mediated tumour.

In another preferred embodiment, the CD 73-mediated tumor is selected from the group consisting of: colorectal cancer, pancreatic cancer, bladder cancer, leukemia, lymphoma, glioma, glioblastoma, melanoma (e.g., malignant melanoma), ovarian cancer, thyroid cancer, esophageal cancer, prostate cancer, breast cancer, liver cancer, non-small cell lung cancer, squamous cell carcinoma, renal cell carcinoma, gastrointestinal tumors, gastric cancer, mesothelioma.

In a fourth aspect of the invention, there is provided a method of preparing an antibody-drug conjugate according to any one of the first aspect of the invention, comprising the steps of:

(1) reacting the antibody with a reducing reagent in a buffer solution to obtain a reduced antibody;

(2) And (2) crosslinking (coupling) the linker-drug conjugate of the formula Ic and the reduced antibody obtained in the step (1) in a mixed solution of a buffer solution and an organic solvent to obtain the antibody-drug conjugate Ia and/or Ib.

In another preferred embodiment, the reaction formula of the preparation method is shown as formula A:

In another preferred example, the antibody in step (1) is reduced with a reducing agent, so that the interchain disulfide bond of the antibody is reduced to generate a sulfhydryl group.

In another preferred embodiment, the reducing agent in step (1) is tris (2-carboxyethyl) phosphine hydrochloride (TCEP), beta-mercaptoethanol, beta-mercaptoethylamine hydrochloride, or Dithiothreitol (DTT).

In another preferred embodiment, the buffer is selected from the group consisting of: potassium dihydrogen phosphate-sodium hydroxide (KH)₂PO₄-NaOH)/sodium chloride (NaCl)/diethyltriaminepentaacetic acid (DTPA) buffer, disodium hydrogen phosphate-citric acid/sodium chloride (NaCl)/diethyltriaminepentaacetic acid (DTPA), boric acid-borax/sodium chloride (NaCl)/diethyltriaminepentaacetic acid (DTPA), histidine-sodium hydroxide/sodium chloride (NaCl)/diethyltriaminepentaacetic acid (DTPA), and PBS/diethyltriaminepentaacetic acid (DTPA).

In another preferred embodiment, in the step (2), the volume of the organic solvent in the reaction solution is not more than 15%.

In another preferred embodiment, the organic solvent in step (2) is selected from the group consisting of: acetonitrile (ACN), Dimethylformamide (DMF), Dimethylacetamide (DMA), dimethyl sulfoxide (DMSO), or a combination thereof.

In another preferred embodiment, in the step (2), the coupling reaction is carried out at 0-37 ℃.

In another preferred embodiment, the step (1) is reduced by using beta-mercaptoethanol, beta-mercaptoethylamine hydrochloride or DTT, and a step (1a) is further included between the step (1) and the step (2): after the reduction reaction is completed, the product is subjected to desalting column or ultrafiltration to remove the reducing agent.

In another preferred embodiment, the antibody-drug conjugate Ia is converted to the antibody-drug conjugate Ib in a buffer at pH 6-8.

In a fifth aspect of the invention, there is provided a method of non-therapeutically inhibiting tumor cells in vitro, comprising the steps of: contacting said tumor cells with an antibody drug conjugate according to any one of the first aspect of the invention or a pharmaceutically acceptable salt or solvate thereof.

In another preferred embodiment, said contacting is performed in an in vitro culture system.

in a sixth aspect of the present invention, there is provided a method for preventing and/or treating a tumor, comprising the steps of: administering to a subject in need thereof a therapeutically effective amount of an antibody-drug conjugate according to any one of the first aspect of the invention or a pharmaceutical composition according to the second aspect of the invention.

in another preferred embodiment, the subject is a mammal, preferably a human.

in another preferred embodiment, the treatment is inhibition of CD 73-mediated tumorigenesis, growth, and/or metastasis.

in a seventh aspect of the invention, there is provided a method of reducing tumor growth in a subject comprising the steps of: combining an effective amount of an antibody drug conjugate according to any one of the first aspect of the invention with one or more treatments selected from the group consisting of: radiation therapy, chemotherapeutic agent therapy, biological therapy, or a combination thereof.

It is to be understood that within the scope of the present invention, the above-described features of the present invention and those specifically described below (e.g., in the examples) may be combined with each other to form new or preferred embodiments. Not to be reiterated herein, but to the extent of space.

drawings

FIG. 1 is a Hydrophobic Interaction Chromatography (HIC) profile of antibody drug conjugate MEDI 9447-vcMMAE;

FIG. 2 is a Hydrophobic Interaction Chromatography (HIC) profile of antibody drug conjugate MEDI9447-ADC 2;

FIG. 3 is a mass spectrum of monoclonal antibody MEDI 9447;

FIG. 4 is a mass spectrum of antibody drug conjugate MEDI 9447-vcMMAE;

FIG. 5 is a mass spectrum of antibody drug conjugate MEDI9447-ADC 2;

FIG. 6 shows the inhibition of cell proliferation in U87MG cells (highly expressed in CD73) in vitro after 6 days of treatment with various concentrations of MEDI 9447-vcMAE, MEDI9447-ADC 2.

FIG. 7 shows the inhibition of cell proliferation in Calu-1 cells (highly expressed in CD73) in vitro after 6 days of treatment with various concentrations of MEDI 9447-vcMAE, MEDI9447-ADC 2.

FIG. 8 shows the inhibition of cell proliferation in Calu-6 cells (highly expressed in CD73) in vitro after 6 days of treatment with various concentrations of MEDI 9447-vcMAE, MEDI9447-ADC 2.

FIG. 9 shows inhibition of NCI-H441 cells (highly expressed in CD73) by MEDI 9447-vcMAE, MEDI9447-ADC2 in vitro cell proliferation 6 days after treatment at various concentrations.

FIG. 10 shows the inhibition of NCI-H292 cells (highly expressed in CD73) cell proliferation in vitro after 6 days of treatment with various concentrations of MEDI 9447-vcMAE, MEDI9447-ADC 2.

FIG. 11 shows the inhibition of MDA-MB-453 cells (low expression of CD73) cell proliferation in vitro after 6 days of treatment with various concentrations of MEDI 9447-vcMAE, MEDI9447-ADC 2.

Detailed Description

The present inventors have extensively and intensively studied, and as a result, aiming at the problems of the antibody-drug coupling technology in the prior art, a novel linker structure (the linker can be fully/partially cross-coupled to the cysteine thiol groups reduced by the light chain-heavy chain and heavy chain-heavy chain disulfide bonds of the antibody) and a drug (formula Ic) (for example, substituted maleimide linker-drug conjugates) are used to achieve site-specific drug coupling to the antibody targeting CD73 by a simple chemical method, and an antibody-drug conjugate targeting CD73 is obtained. The antibody drug conjugate obtained by applying the coupling method has a narrower distribution of drug/antibody ratio (DAR) (m is 3.5-4.5; preferably 3.8-4.2, more preferably 3.9-4.1, and most preferably 4.0) compared with the conventional antibody drug conjugate. The method can improve the uniformity of the drug, save a large amount of resources for the research of process and quality control, and simultaneously can improve the stability, the drug effect, the safety and other properties of the conjugate. The experimental results show that the antibody-drug conjugates (e.g., MEDI9447-vcMMAE, MEDI9447-ADC1, ME DI9447-ADC2, MEDI9447-ADC3, MEDI9447-ADC4, MEDI9447-ADC5, and ME DI9447-ADC6) have significant anti-tumor effects. The invention also relates to a pharmaceutical application of the anti-CD 73 antibody-drug conjugate and an effect of the anti-CD 73 antibody-drug conjugate in tumor inhibition or prevention. On this basis, the inventors have completed the present invention.

Term(s) for

As used herein, the terms "antibody drug conjugate", "antibody drug conjugate", "antibody-drug conjugate", "immunoconjugate", and "immunoconjugate" are used interchangeably to refer to a conjugate of an antibody (Ab) or an active fragment thereof and a linker-drug conjugate of formula Ic or a pharmaceutically acceptable salt or solvate thereof.

as used herein, the terms "antibody drug conjugate of the invention", "antibody and drug conjugate of the invention", or "antibody drug conjugate of the invention", "ADC of the invention" are used interchangeably and refer to a conjugate of an antibody of the invention or an active fragment thereof directed to CD73 with a linker-drug conjugate shown in formula Ic or a pharmaceutically acceptable salt or solvate thereof.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. As used herein, the term "about" when used in reference to a specifically recited value means that the value may vary by no more than 1% from the recited value. For example, the expression "about 100" includes 99 and 101 and all values in between (e.g., 99.1, 99.2, 99.3, 99.4, etc.).

as used herein, unless otherwise specified, the term "C1-C4 alkyl" refers to a straight or branched chain alkyl group having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, or the like.

the term "C1-C4 alkoxy" refers to a straight or branched chain alkoxy group having 1 to 4 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, or the like.

The term "halogen" refers to F, Cl, Br and I.

the term "C6-C10 aryl" refers to aryl groups having 6-10 carbon atoms, such as phenyl, naphthyl, and the like, which may be substituted or unsubstituted.

The term "C6-C10 arylene" refers to arylene groups having 6 to 10 carbon atoms, such as phenylene, naphthylene, and the like, which may be substituted or unsubstituted.

The terms "5-12 membered heteroaryl", "5-12 membered heteroarylene" refer to heteroaryl or heteroarylene groups, preferably 5-8 membered heteroaryl or heteroarylene groups, having 5-12 carbon atoms and one or more (preferably 1-3) heteroatoms selected from O, S and/or N. The heteroaryl or heteroarylene group may be substituted or unsubstituted.

in the present invention, the term "pharmaceutically acceptable" ingredient refers to a substance that is suitable for use in humans and/or animals without undue adverse side effects (such as toxicity, irritation, and allergic response), i.e., at a reasonable benefit/risk ratio.

In the present invention, the term "effective amount" refers to an amount of a therapeutic agent that treats, alleviates, or prevents a target disease or condition, or an amount that exhibits a detectable therapeutic or prophylactic effect. The precise effective amount for a subject will depend upon the size and health of the subject, the nature and extent of the disorder, and the therapeutic agent and/or combination of therapeutic agents selected for administration. Therefore, it is not useful to specify an exact effective amount in advance. However, for a given condition, the effective amount can be determined by routine experimentation and can be determined by a clinician.

unless otherwise specified, all occurrences of a compound in the present invention are intended to include all possible optical isomers, such as a single chiral compound, or a mixture of various chiral compounds (i.e., a racemate). In all compounds of the present invention, each chiral carbon atom may optionally be in the R configuration or the S configuration, or a mixture of the R configuration and the S configuration.

As used herein, the term "compounds of the invention" refers to compounds of formula Ic. The term also includes various crystalline forms, pharmaceutically acceptable salts, hydrates or solvate compounds of the compound of formula Ic.

As used herein, the term "pharmaceutically acceptable salt" refers to a salt of a compound of the present invention with an acid or base that is suitable for use as a pharmaceutical. Pharmaceutically acceptable salts include inorganic and organic salts. One preferred class of salts is that formed by reacting a compound of the present invention with an acid. Suitable acids for forming the salts include, but are not limited to: inorganic acids such as hydrochloric acid, hydrobromic acid, hydrofluoric acid, sulfuric acid, nitric acid, phosphoric acid, etc., organic acids such as formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, lactic acid, malic acid, tartaric acid, citric acid, picric acid, methanesulfonic acid, phenylmethanesulfonic acid, benzenesulfonic acid, etc.; and acidic amino acids such as aspartic acid and glutamic acid.

Unless otherwise specified, "amino acid" as used herein is intended to include any conventional amino acid, such as aspartic acid, glutamic acid, cysteine, asparagine, phenylalanine, glutamine, tyrosine, serine, methionine (methionine), tryptophan, glycine, valine, leucine, alanine, isoleucine, proline, threonine, histidine, lysine, arginine.

When a trade name is used herein, the trade name is intended to include the trade name product formulation, its corresponding imitation drug, and the active pharmaceutical component of the trade name product.

Antibodies

as used herein, the term "antibody" or "immunoglobulin" is an heterotetrameric glycan protein of about 150000 daltons with the same structural features, consisting of two identical light chains (L) and two identical heavy chains (H). Each light chain is linked to a heavy chain by one covalent disulfide bond, while the number of disulfide bonds varies between heavy chains of different immunoglobulin isotypes. Each heavy and light chain also has regularly spaced intrachain disulfide bonds. Each heavy chain has at one end a variable region (VH) followed by a plurality of constant regions. Each light chain has a variable domain (VL) at one end and a constant domain at the other end; the constant region of the light chain is opposite the first constant region of the heavy chain, and the variable region of the light chain is opposite the variable region of the heavy chain. Particular amino acid residues form the interface between the variable regions of the light and heavy chains.

as used herein, the term "variable" means that certain portions of the variable regions in an antibody differ in sequence, which results in the binding and specificity of each particular antibody for its particular antigen. However, the variability is not evenly distributed throughout the antibody variable region. It is concentrated in three segments called Complementarity Determining Regions (CDRs) or hypervariable regions in the light and heavy chain variable regions. The more conserved portions of the variable regions are called Framework Regions (FR). The variable regions of native heavy and light chains each comprise four FR regions, which are in a substantially β -sheet configuration, connected by three CDRs that form a connecting loop, and in some cases may form part of a β -sheet structure. The CDRs in each chain are held close together by the FR region and form the antigen binding site of the antibody with the CDRs of the other chain (see Kabat et al, NIH Publ. No.91-3242, Vol I, 647-669 (1991)). The constant regions are not directly involved in the binding of antibodies to antigens, but they exhibit different effector functions, such as participation in antibody-dependent cytotoxicity of antibodies.

The "light chains" of vertebrate antibodies (immunoglobulins) can be assigned to one of two distinct classes (termed kappa and lambda) based on the amino acid sequence of their constant regions. Immunoglobulins can be assigned to different classes based on the amino acid sequence of their heavy chain constant regions. There are mainly 5 classes of immunoglobulins: IgA, IgD, IgE, IgG and IgM, some of which can be further divided into subclasses (isotypes), such as IgG1, IgG2, IgG3, IgG4, IgA and IgA 2. The heavy chain constant regions corresponding to different classes of immunoglobulins are referred to as α, δ, ε, γ, and μ, respectively. The subunit structures and three-dimensional configurations of different classes of immunoglobulins are well known to those skilled in the art.

in general, the antigen binding properties of an antibody can be described by 3 specific regions in the heavy and light chain variable regions, called variable regions (CDRs), which are separated into 4 Framework Regions (FRs), the amino acid sequences of the 4 FRs being relatively conserved and not directly involved in the binding reaction. These CDRs form a loop structure, and the β -sheets formed by the FRs between them are spatially close to each other, and the CDRs on the heavy chain and the CDRs on the corresponding light chain constitute the antigen binding site of the antibody. It is possible to determine which amino acids constitute the FR or CDR regions by comparing the amino acid sequences of antibodies of the same type.

The invention includes not only intact antibodies, but also fragments of immunologically active antibodies (e.g., antigen-binding fragments) or fusion proteins of antibodies with other sequences. Accordingly, the invention also includes fragments, derivatives and analogs of the antibodies.

In the present invention, antibodies include murine, chimeric, humanized or fully human antibodies prepared using techniques well known to those skilled in the art. Recombinant antibodies, such as chimeric and humanized monoclonal antibodies, including human and non-human portions, can be obtained by standard DNA recombination techniques, and are useful antibodies. A chimeric antibody is a molecule in which different portions are derived from different animal species, such as chimeric antibodies having a variable region derived from a murine monoclonal antibody, and a constant region derived from a human immunoglobulin (see, e.g., U.S. Pat. No. 4,816,567 and U.S. Pat. No. 4,816,397, which are hereby incorporated by reference in their entirety). Humanized antibodies refer to antibody molecules derived from non-human species having one or more Complementarity Determining Regions (CDRs) derived from the non-human species and a framework region derived from a human immunoglobulin molecule (see U.S. Pat. No. 5,585,089, herein incorporated by reference in its entirety). These chimeric and humanized monoclonal antibodies can be prepared using recombinant DNA techniques well known in the art.

In the present invention, the antibody may be monospecific, bispecific, trispecific, or more multispecific.

In the present invention, the antibody of the present invention also includes conservative variants thereof, which means that at most 10, preferably at most 8, more preferably at most 5, and most preferably at most 3 amino acids are replaced by amino acids having similar or similar properties as compared with the amino acid sequence of the antibody of the present invention to form a polypeptide. These conservative variants are preferably produced by amino acid substitutions according to Table A.

TABLE A

Initial residue(s)	Representative substitutions	preferred substitutions
			Ala(A)	Val；Leu；Ile	Val
Arg(R)	Lys；Gln；Asn	Lys
			Asn(N)	Gln；His；Lys；Arg	Gln
Asp(D)	Glu	Glu
			Cys(C)	Ser	Ser
Gln(Q)	Asn	Asn
			Glu(E)	Asp	Asp
Gly(G)	Pro；Ala	Ala
			His(H)	Asn；Gln；Lys；Arg	Arg
Ile(I)	Leu；Val；Met；Ala；Phe	Leu
			Leu(L)	Ile；Val；Met；Ala；Phe	Ile
Lys(K)	Arg；Gln；Asn	Arg
			Met(M)	Leu；Phe；Ile	Leu
Phe(F)	Leu；Val；Ile；Ala；Tyr	Leu
			Pro(P)	Ala	Ala
Ser(S)	Thr	Thr
			Thr(T)	Ser	Ser
Trp(W)	Tyr；Phe	Tyr
			Tyr(Y)	Trp；Phe；Thr；Ser	Phe
Val(V)	Ile；Leu；Met；Phe；Ala	Leu

the term "antibody" is used herein in its broadest sense and specifically covers monoclonal antibodies, polyclonal antibodies, dimers, multimers, multispecific antibodies (e.g., bispecific antibodies) and antibody fragments so long as they exhibit the desired biological activity (Miller et al (2003) Journal of Immunology 170: 4854-4861). The antibody may be murine, human, humanized, chimeric, or derived from other species. Antibodies are proteins produced by the immune system that are capable of recognizing and binding specific antigens (Janeway, c., Travers, p., Walport, m., shmchik (2001) immunology biology,5th ed., Garland publishing, new york). Target antigens typically have a large number of binding sites, also referred to as epitopes, that are recognized by the CDRs of various antibodies. Each antibody that specifically binds to a different epitope has a different structure. Thus, an antigen may have more than one corresponding antibody. Antibodies include full-long immunoglobulin molecules or immunologically active portions of full-long immunoglobulin molecules, i.e., molecules that contain an antigen or portion thereof that specifically binds to a target of interest, including, but not limited to, cancer cells or cells that produce autoimmune antibodies associated with autoimmune diseases. The immunoglobulins disclosed herein may be of any type (e.g., IgG, IgE, IgM, IgD, and IgA), class (e.g., IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2) or subclass of immunoglobulin molecule. The immunoglobulin may be derived from any species. Preferably, however, the immunoglobulin is of human, murine or rabbit origin.

An "antibody fragment" comprises a portion of a full-length antibody, typically the antigen-binding or variable region thereof. Examples of antibody fragments include: fab, Fab ', F (ab')2 and Fv fragments; a diabody; a linear antibody; minibody (Olafsen et al (2004) Protein Eng. design & Sel.17(4): 315-; fragments prepared from Fab expression libraries; anti-idiotypic (anti-Id) antibodies; CDRs (complementarity determining regions); and an epitope-binding fragment of any of the above that binds in an immunospecific manner to a cancer cell antigen, a viral antigen, or a microbial antigen; a single-chain antibody molecule; and multispecific antibodies formed from antibody fragments.

The antibody constituting the antibody-drug conjugate of the present invention preferably retains its antigen-binding ability in its original wild state. Thus, the antibodies of the invention are capable of, preferably specifically, binding to an antigen.

Typically, the antibodies of the invention are antibodies capable of binding to CD 73.

Preparation of antibodies

The sequence of the DNA molecule of the antibody or fragment thereof of the present invention can be obtained by a conventional technique, for example, by PCR amplification or genomic library screening. Alternatively, the coding sequences for the light and heavy chains may be fused together to form a single chain antibody.

once the sequence of interest has been obtained, it can be obtained in large quantities by recombinant methods. This is usually done by cloning it into a vector, transferring it into a cell, and isolating the relevant sequence from the propagated host cell by conventional methods.

In addition, the sequence can be synthesized by artificial synthesis, especially when the fragment length is short. Generally, fragments with long sequences are obtained by first synthesizing a plurality of small fragments and then ligating them.

At present, the DNA sequence encoding the antibody of the invention (or a fragment thereof, or a derivative thereof) has been obtained entirely by chemical synthesis. The DNA sequence may then be introduced into various existing DNA molecules (or vectors, for example) and cells known in the art. Furthermore, mutations can also be introduced into the protein sequences of the invention by chemical synthesis.

The invention also relates to a vector comprising a suitable DNA sequence as described above and a suitable promoter or control sequence. These vectors may be used to transform an appropriate host cell so that it can express the protein.

The host cell may be a prokaryotic cell, such as a bacterial cell; or lower eukaryotic cells, such as yeast cells; or higher eukaryotic cells, such as mammalian cells. Preferred animal cells include (but are not limited to): CHO-S, HEK-293 cells.

Typically, the transformed host cells are cultured under conditions suitable for expression of the antibodies of the invention. The antibody of the invention is then purified by conventional immunoglobulin purification procedures, such as protein A-Sepharose, hydroxylapatite chromatography, gel electrophoresis, dialysis, ion exchange chromatography, hydrophobic chromatography, molecular sieve chromatography or affinity chromatography, using conventional separation and purification means well known to those skilled in the art.

The resulting monoclonal antibodies can be identified by conventional means. For example, the binding specificity of a monoclonal antibody can be determined by immunoprecipitation or by an in vitro binding assay, such as Radioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA). The binding affinity of monoclonal antibodies can be determined, for example, by Scatchard analysis by Munson et al, anal. biochem.,107:220 (1980).

The antibody of the present invention may be expressed intracellularly or on the cell membrane, or secreted extracellularly. If necessary, the recombinant protein can be isolated and purified by various separation methods using its physical, chemical and other properties. These methods are well known to those skilled in the art. Examples of such methods include, but are not limited to: conventional renaturation treatment, treatment with a protein precipitant (such as salt precipitation), centrifugation, cell lysis by osmosis, sonication, ultracentrifugation, molecular sieve chromatography (gel filtration), adsorption chromatography, ion exchange chromatography, High Performance Liquid Chromatography (HPLC), and other various liquid chromatography techniques, and combinations thereof.

medicine

As used herein, "drug" broadly refers to any compound having a desired biological activity and having reactive functional groups for the preparation of conjugates of the invention. Desirable biological activities include, diagnosing, curing, alleviating, treating, preventing diseases in humans or other animals. Thus, the term "drug" refers to compounds that include the official national pharmacopoeia, as well as recognized drugs such as the official homeopathic pharmacopoeia of the united states, the official national formulary, or any subsidy thereof, so long as they possess the requisite reactive functional groups. Typical drugs are listed in physician's case medication reference (PDR) and the orange book of the united states Food and Drug Administration (FDA). It is understood that as new drugs continue to be discovered and developed, these drugs should also be incorporated into the "drugs" of the conjugate drugs described herein.

drugs that may be used to construct the ADCs of the present invention include, but are not limited to: a cytotoxic agent (e.g., a cytotoxic small molecule drug).

The term "cytotoxic agent" refers to a substance that inhibits or prevents a cell from expressing an activity, a cell function, and/or causing cell destruction. The term includes radioisotopes, chemotherapeutic agents, and toxins, such as small molecule toxins or enzymatically active toxins of bacterial, fungal, plant or animal origin, including fragments and/or variants thereof. Examples of cytotoxic agents include, but are not limited to: auristatins (e.g., auristatin E, auristatin F, MMAE, and MMAF), chlortetracycline, maytansinoids, ricin A-chain, combretastatin, duocarmycin, dolastatin, doxorubicin, daunorubicin, paclitaxel, cisplatin, cc1065, ethidium bromide, mitomycin, etoposide, tenoposide (tenoposide), vincristine, vinblastine, colchicine, dihydroxyanthrax dione, actinomycin, diphtheria toxin, Pseudomonas Exotoxin (PE) A, PE40, abrin A chain, anemonin A chain, alpha-sarcina, gelonin, mitogellin (mitogellin), restrictocin (retstricin), phenomycin, enomycin, curcin (curcin), crotin, calicheamicin, soapwort (Saonafia) and other chemical inhibitors, and radioisotopes such as At211, I131, I125, Y90, Re186, Re188, Sm153, Bi212 or 213, P32 and radioisotopes of Lu including Lu 177. The antibody may also be conjugated to an anticancer prodrug activating enzyme capable of converting the prodrug into its active form.

Preferred small molecule drugs are highly cytotoxic compounds, preferably monomethyl auristatins (monomethylauristatins), calicheamicins, maytansinoids, or combinations thereof; more preferably selected from: monomethyl auristatin-e (mmae), monomethyl auristatin-d (mmad), monomethyl auristatin-f (mmaf), or combinations thereof.

Preferably, the medicament is: a cytotoxic drug for cancer therapy, or a protein or polypeptide having a desired biological activity, e.g., a toxin such as abrin, ricin a, pseudomonas exotoxin, and diphtheria toxin; other suitable proteins include tumor necrosis factor, alpha-interferon, beta-interferon, neuronal growth factor, platelet derived growth factor, tissue type fibroblast lyso-growth factor, and biological response modifying agents such as lymphokines, interleukin-1 (IL-1), interleukin-2 (IL-2), interleukin-6 (IL-6), granulocyte macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor, or other growth factors.

A preferred drug of the invention is maytansine or a maytansinoid. Maytansinoids inhibit cell proliferation by inhibiting tubulin microtubule formation. Maytansinoids are derivatives of maytansine. Both maytansinoids and maytansinoids have highly potent cytotoxicity, but they have great limitations in clinical applications for cancer therapy, mainly due to the low selectivity of such molecules for tumors. However, this high cytotoxicity has prompted them to be the drug moiety of choice for antibody drug conjugates. The structure of deacetylmaytansine is listed below.

Another preferred drug of the invention is an auristatin peptide drug. The auristatin peptide drug is the analog of Dolastatin10 (Dolastatin10), which is a polypeptide with biological activity separated from sea mollusk sea rabbit. Dolastatin10 inhibits tubulin polymerization by binding to tubulin (the same binding domain as vincristine). Dolastatin10, auristatin peptide PE, auristatin peptide E are all linear polypeptides, containing four amino acids (three of which are unique to dolastatin compounds) and a C-terminal amide group. Two representative auristatin peptide compounds, monomethyl auristatin peptide e (mmae) and monomethyl auristatin peptide f (mmaf), are the first choice drugs for antibody drug conjugates.

Monomethyl Auristatin E(MMAE)

Monomethyl Auristatin F(MMAF)

Monomethyl Dolastatin 10(MMAD)

another preferred agent of the invention is Tubulysin (Tubulysin). Tubulysins, first isolated by the research group from myxobacterial cultures, are very potent inhibitors of cell growth, acting by inhibiting tubulin polymerization and thereby inducing apoptosis. Tubulysin D, the most potent one, has 10 to 100-fold more activity than most other tubulin modulators, including epothilones, vinblastine and paclitaxel. Paclitaxel and vinblastine are currently used in the treatment of a variety of cancers, while epothilone derivatives are being evaluated for activity in clinical trials. Synthetic derivatives of tubulysin D will provide the necessary information regarding inhibition and key binding interactions and may have superior properties as anticancer agents either as separate entities or as chemical warheads on targeting antibodies or ligands. Tubulysin D is a complex tetrapeptide that can be divided into four regions, Mep (D-N-methylpiperidinecarboxylic acid), Ile (isoleucine), Tuv (tubulivaline) and Tup (tubulphenylalanine), as shown in the following formula:

Another preferred agent of the invention is a cryptophycin derivative of microbial origin which inhibits microtubule polymerization. Cryptophycin is a novel antitumor active substance which is separated from a culture of blue algae and can inhibit the generation of microtubules, and has activity on various tumors. Cryptophycin is a fat-soluble compound, contains 2 peptide bonds and 2 ester bonds, and has 5 optical active centers and 1 epoxy group. The dipeptide diester bonds are all in one macrocyclic structure. The Cryptophycin derivatives CP1 and CP2 have the following structures:

another preferred agent of the invention is the novel antimicrotubule agent Taltobulin (HTI-286, SPA-110). Taltobulin inhibits polymerization of purified microtubules, interferes with intracellular microtubule organization, induces mitotic block, and induces apoptosis. Taltobulin is a potent inhibitor of cell proliferation, and has an average IC50 of 2.5nM for 18 human tumor cell lines. In contrast to currently used antimicrotubule agents, Taltobulin is not a suitable substrate for p-glycoprotein, wherein the structure of Taltobulin is shown by the following formula:

A medicine is camptothecin derivative SN-38. SN-38 is a biologically active metabolite of irinotecan hydrochloride (CPT-11), a class of topoisomerase inhibitors. SN-38 causes the strongest inhibition of DNA topoisomerase I, inhibits DNA synthesis dose-and time-dependently, and causes frequent DNA single strand breaks. Wherein the structure of SN-38 is shown as the following formula:

Another preferred agent of the invention is the Amanitin drug (alpha-Amanitin), which has the structure shown below. alpha-Amanitin is a mycotoxin from the mushroom Amanita phillyides (Amanita villoides), a bicyclic octapeptide, which inhibits transcription of eukaryotic RNA polymerase II and RNA polymerase III.

Another preferred agent of the invention is benzodiazole antibiotic (duocarmycins, CC-1065, etc.) and other cyclopropylpyrrol-indol-4-one (CPI) derivatives. Such compounds are effective DNA minor groove binding-alkylating agents. Cyclopropylbenzindol-4-one (CBI) analogues are more stable in chemical structure, more biologically active, and easier to synthesize than their parent compounds containing the natural CPI alkylated subunit. One representative CBI derivative is the phenolic hydroxyl protected derivative CBI, with reduced prodrug toxicity and enhanced water solubility (where the CBI-seco-like general structural formula is shown below):

Another preferred agent of the invention is a pyrrolobenzodiazepine (pyrrolo [2,1-c ] [1,4] ben zodi-azepines, PBDs) or a PBD dimer (PBD dimers). PBDs are a class of natural products produced by Streptomyces and have the unique property of being able to form non-twisted covalent adducts in the DNA minor groove, specifically at the purine-guanine-purine sequence. The use of PBD as part of a small molecule strategy to target locked DNA sequences and as a novel anti-cancer and anti-bacterial drug has attracted increasing interest. The hydroxyl groups of C8/C8' of two PBD units are connected by a flexible carbon chain, and the obtained dimer has enhanced biological activity. PBD dimers are thought to produce sequence selective DNA damage, such as reverse order 5'-Pu-GATC-Py-3' interchain cross-linking, resulting in their biological activity. These compounds have been shown to be highly potent cytotoxic drugs and may be used as drug candidates for antibody drug conjugates.

Another preferred drug of the invention is a PNU-159682 derivative, PNU-159682 being the major active metabolite of Nemorubicin in human liver microsomes, with a 3000-fold increase in activity compared to MMDX and doxorubicin.

On the other hand, the drug is not limited to only the above-mentioned classes, but also includes all drugs that can be used for the antibody drug conjugate. And especially those capable of coordinating through an amide linkage with a linker, such as by having a basic amine group (primary or secondary), for example the structures of cytotoxins D1-D14 shown above.

Connector

According to the mechanism of drug release in cells, "linker" or "linker of antibody drug conjugate" can be divided into two categories: non-cleavable linkers and cleavable linkers.

For antibody drug conjugates containing a non-cleavable linker, the drug release mechanism is: after the conjugate is combined with antigen and endocytosed by cells, the antibody is enzymolyzed in lysosome to release active molecules consisting of small molecular drugs, linkers and antibody amino acid residues. The resulting structural change in the drug molecule does not reduce its cytotoxicity, but because the active molecule is charged (amino acid residues), it cannot penetrate into neighboring cells. Thus, such active drugs cannot kill adjacent tumor cells that do not express the targeted antigen (antigen negative cells) (bystandeffect).

Cleavable linkers, as the name implies, can cleave within the target cell and release the active drug (small molecule drug itself). Cleavable linkers can be divided into two main classes: chemically labile linkers and enzyme labile linkers. Chemically labile linkers can be selectively cleaved due to differences in plasma and cytoplasmic properties. Such properties include pH, glutathione concentration, and the like. The pH sensitive linker is often also referred to as an acid cleavable linker. Such a linker is relatively stable in the neutral environment of blood (pH7.3-7.5), but will be hydrolyzed in weakly acidic endosomes (pH5.0-6.5) and lysosomes (pH 4.5-5.0). The first generation of antibody drug conjugates mostly used such linkers as hydrazones, carbonates, acetals, ketals. Antibody drug conjugates based on such linkers typically have a short half-life (2-3 days) due to the limited plasma stability of the acid-cleaved linker. This short half-life limits to some extent the use of pH sensitive linkers in the next generation of antibody drug conjugates.

Linkers that are sensitive to glutathione are also known as disulfide linkers. Drug release is based on the difference between high intracellular glutathione concentrations (millimolar range) and relatively low glutathione concentrations in the blood (micromolar range). This is particularly true for tumor cells, where their low oxygen content leads to enhanced activity of the reductase and thus to higher glutathione concentrations. Disulfide bonds are thermodynamically stable and therefore have better stability in plasma.

enzyme-labile linkers, such as peptide linkers, allow for better control of drug release. The peptide linker can be effectively cleaved by an endolytic protease, such as Cathepsin B or plasmin (the content of such enzymes is increased in some tumor tissues). This peptide linkage is considered to be very stable in the plasma circulation, since proteases are generally inactive due to an undesirable extracellular pH and serum protease inhibitors. In view of higher plasma stability and good intracellular cleavage selectivity and effectiveness, enzyme-labile linkers are widely used as cleavable linkers for antibody drug conjugates. Typical enzyme labile linkers include Val-Cit (VC), Phe-Lys, and the like.

The self-releasing linker is typically either chimeric between the cleavable linker and the active drug or is itself part of the cleavable linker. The mechanism of action of the self-releasing linker is: self-releasing linkers are capable of undergoing a structural rearrangement spontaneously upon cleavage of the cleavable linker under suitable conditions, thereby releasing the active drug attached thereto. Common suicide linkers include para-aminobenzols (PAB) and beta-glucuronides (beta-Glucuronide), among others.

The present invention provides linkers or coupling reagents comprising a diarylthiomaleimide unit and a coupling group. The diarylthiomaleimide units are used to crosslink the sulfhydryl groups between antibody chains (after reduction), while the coupling groups are used to couple with small molecule drugs or drug-linker units. These ADCs are homogeneous and more stable than ADCs containing monodentate linkers due to the bidentate binding of the diarylthiomaleimide unit to the two sulfur atoms of the open cysteine-cysteine disulfide bond in the antibody. They will therefore have an increased in vivo half-life, reduce the amount of systemically released cytotoxins, and be safer for pharmaceutical properties than ADCs with monodentate linkers.

In another aspect, the resulting drug-linker unit is conjugated to an antibody via the linker, resulting in a conjugate with partial interchain cross-linking. Compared with the traditional antibody drug conjugate, the antibody drug conjugate prepared by the method has narrower drug/antibody ratio (DAR) distribution, thereby greatly improving the product uniformity and the pharmacological property uniformity. The antibody drug conjugate can be used for targeted delivery of drugs to target cell populations, such as tumor cells. The antibody drug conjugate can be specifically bound to a cell surface protein, and the resulting conjugate can then be endocytosed by the cell. Within the cell, the drug is released in the form of the active drug to produce efficacy. Antibodies include chimeric antibodies, humanized antibodies, human antibodies; an antibody fragment that binds to an antigen; or an antibody Fc fusion protein; or a protein. A "drug" is a highly active drug (see definitions section), which in some cases may be polyethylene glycol.

Linker-drug conjugates

In the present invention, the linker-drug conjugate includes a substituted maleimide-based linker-drug conjugate shown by formula Ic or a pharmaceutically acceptable salt or solvate thereof;

Wherein the content of the first and second substances,

R is X or ArS-,

X is selected from the group consisting of: halogen, preferably bromine or iodine;

L₂is a chemical bond or an AA-PAB structure; wherein AA is dipeptide or tripeptide or tetrapeptide fragment (i.e. fragment formed by connecting 2-4 amino acids through peptide bond), PAB is p-aminobenzyl carbamoyl;

CTD is bonded to L through an amide bond₂The cytotoxic small molecule drug and/or the drug for treating autoimmune diseases and anti-inflammation。

Typically, in the present invention, the compound of formula Ic is selected from the group consisting of:

anti-CD 73 antibodies

In a preferred class of ADCs of the present invention, the antibody moiety is an anti-CD 73 antibody. The antibody is selected from: an antibody of animal origin, a chimeric antibody, a humanized antibody, a fully human antibody, or a combination thereof.

Preferably, the anti-CD 73 antibody is MEDI 9447.

For information on the sequence and activity of these excellent anti-CD 73 antibodies, see WO2016075176a 1. This document is incorporated by reference herein in its entirety.

antibody-drug conjugates

the antibody drug conjugate provided by the invention consists of an antibody, a linker and a drug, wherein the linker is a cleavable linker combination or a non-cleavable linker.

Antibodies are globular proteins containing a series of amino acid sites that can be used to couple drug-linkers. Due to their tertiary and quaternary structure, only solvent accessible amino acids are available for coupling. In fact, high yields of coupling usually occur on the epsilon-amino group of a lysine residue or on the sulfhydryl group of a cysteine residue.

The large number of lysine side chains on the surface of the antibody protein results in a large number of sites available for drug conjugation, resulting in the generation of antibody drug conjugates as a mixture containing different numbers of drug conjugates (drug/antibody ratio, DAR) and conjugation sites.

The coupling product provided by the invention is still a mixture, but has a narrow DAR distribution range compared with the antibody drug conjugate obtained by the conventional coupling method. The average DAR value is close to 4, and the average DAR value is close to the range of the optimal antibody drug conjugate (2-4). In addition, the conjugate product contained little or no naked antibody (DAR ═ 0), and this fraction did not contribute to cytotoxic activity. Also, the coupling product does not contain a heavy coupling product (DAR ═ 8), and this fraction is cleared rapidly in vivo, relative to the low DAR fraction. Therefore, the heterogeneity of the antibody drug conjugate product provided by the invention is greatly improved.

In a preferred class of ADCs of the present invention, the antibody moiety is that of CD 73. The antibody is selected from: an antibody of animal origin, a chimeric antibody, a humanized antibody, or a combination thereof.

preferably, the anti-CD 73 antibody is MEDI 9447. The corresponding antibody-drug conjugates were:

MEDI9447-vcMMAE、MEDI9447-ADC1、MEDI9447-ADC2、MEDI9447-ADC3、MEDI9447-ADC4、MEDI9447-ADC5、MEDI9447-ADC6。

Method for preparing antibody-drug conjugate

The preparation route of the antibody drug conjugate is shown below. The interchain disulfide bond of the antibody is reduced, resulting in 2n (e.g., 4) sulfhydryl groups. The substituted maleimide linker-drug conjugate (compound of formula Ic) of the present invention is cross-linked with reduced antibody thiol groups to generate the corresponding antibody drug conjugate, wherein the antibody drug conjugate exists in one or two of the following forms:

wherein R, Ar', L1, L2 and CTD are as described above.

One typical preparation method includes: diluting the antibody stock solution to 2-10mg/mL with reaction buffer solution, adding 140-fold excess molar ratio Dithiothreitol (DTT) or adding 6.0-20-fold excessStirring the reaction solution of tris (2-carboxyethyl) phosphine hydrochloride (TCEP) in a molar ratio at the temperature of between 10 and 35 ℃ for 2 to 48 hours; the reaction buffer described herein may be a buffer prepared in the following ratio: 50mM potassium dihydrogen phosphate-sodium hydroxide (KH)₂PO₄-NaOH)/150mM sodium chloride (NaCl)/1mM diethyltriaminepentaacetic acid (DTPA), pH 6-9; 50mM disodium hydrogen phosphate-citric acid/150 mM sodium chloride (NaCl)/1mM diethyltriaminepentaacetic acid (DTPA), pH 6-9; 50mM boric acid-borax/150 mM sodium chloride (NaCl)/1mM diethyltriaminepentaacetic acid (DTPA), pH 6-9; 50mM histidine-sodium hydroxide/150 mM sodium chloride (NaCl)/1mM diethyltriaminepentaacetic acid (DTPA), pH 6-9 and PBS/1mM diethyltriaminepentaacetic acid (DTPA), pH 6-9.

Cooling the reaction liquid to 0-10 ℃, if adopting DTT reduction, removing excessive DTT by a desalting column or ultrafiltration after the reduction reaction is finished, adding a substituted maleimide compound (10mg/ml is dissolved in Acetonitrile (ACN), dimethyl sulfoxide (DMSO), dimethyl formamide (DMF) or diethyl acetamide (DMA) in advance), ensuring that the volume ratio of an organic solvent in the reaction liquid is not more than 15%, and stirring the coupling reaction at 0-37 ℃ for 2-4 hours. If TCEP is used for reduction, the substituted maleimide compound can be directly added for coupling without removing the residual TCEP.

The coupling reaction mixture was purified by filtration using sodium succinate/NaCl buffer or histidine-acetic acid/sucrose gel using a desalting column, and peak samples were collected according to UV280 UV absorbance. Or ultrafiltering for several times. Then filtering and sterilizing, and storing the obtained product at low temperature. The temperature is preferably from-100 to 60 ℃ and the pore size of the filter unit is preferably from 0.15 to 0.3. mu.m.

the obtained antibody drug conjugate has a uniform drug antibody coupling ratio (DAR). With the differently substituted maleimide linkers (linker fragments) of the present invention, the ADC products are very uniform (typically at least 60%, at least 70%, at least 80%, at least 90% or more of all ADCs are occupied by DAR dominant products (e.g., DAR of about 4)). For the ADC with some difference in DAR, if a sample with better homogeneity is required, the following methods can be further used for separation and purification: hydrophobic Interaction Chromatography (HIC), Size Exclusion Chromatography (SEC), Ion Exchange Chromatography (IEC).

According to the coupling method provided by the invention, the toxin small molecule is coupled to the targeting CD73 antibody through the specific connector, and the lethality of the antibody to tumor cells is greatly improved on the basis of not changing the affinity of the antibody.

pharmaceutical compositions and methods of administration

Since the antibody-drug conjugate provided by the present invention can be targeted to a specific cell population, and bound to a cell surface specific protein (antigen), so that the drug is released into the cell in an active form by endocytosis or drug infiltration of the conjugate, the antibody-drug conjugate of the present invention can be used for treating a target disease, and the above-mentioned antibody-drug conjugate can be administered to a subject (e.g., human) in a therapeutically effective amount by an appropriate route. The subject in need of treatment can be a patient at risk for, or suspected of having, a condition associated with the activity or expression of a particular antigen. Such patients can be identified by routine physical examination.

Conventional methods, known to those of ordinary skill in the medical arts, may be used to administer a pharmaceutical composition to a subject, depending on the type of disease to be treated or the site of the disease. The composition may also be administered by other conventional routes, for example, orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or by implantation. The term "parenteral" as used herein includes subcutaneous, intradermal, intravenous, intramuscular, intraarticular, intraarterial, intrasynovial, intrasternal, intrathecal, intralesional and intracranial injection or infusion techniques. Furthermore, it may be administered to the subject of depot injectable or biodegradable materials and methods by administration of an injectable depot route, for example using 1-, 3-, or 6-month depot.

Injectable compositions may contain various carriers such as vegetable oils, dimethylacetamide (dimethyl acetamide), dimethylformamide, ethyl lactate, ethyl carbonate, isopropyl myristate, ethanol, polyols (glycerol, propylene glycol, liquid polyethylene glycols, and the like). For intravenous injection, the water-soluble antibody may be administered by a drip method, whereby a pharmaceutical preparation containing the antibody and a physiologically acceptable excipient is infused. Physiologically acceptable excipients may include, for example, 5% dextrose, 0.9% saline, ringer's solution, or other suitable excipients. Intramuscular formulations, e.g., sterile formulations of an appropriate soluble salt form of the antibody, may be dissolved and administered with a pharmaceutically acceptable excipient such as a water-change injection, 0.9% saline, or 5% dextrose solution.

When treated with the antibody-drug conjugates of the invention, delivery can be by methods conventional in the art. For example, it can be introduced into cells by using liposomes, hydrogels, cyclodextrins, biodegradable nanocapsules, or bioadhesive microspheres. Alternatively, the nucleic acid or vector may be delivered locally by direct injection or by use of an infusion pump. Other methods include various transport and carrier systems through the use of conjugates and biodegradable polymers.

The pharmaceutical composition of the present invention comprises a safe and effective amount of the antibody-drug conjugate of the present invention and a pharmaceutically acceptable carrier. Such vectors include (but are not limited to): saline, buffer, glucose, water, glycerol, ethanol, and combinations thereof. In general, the pharmaceutical preparations should be adapted to the mode of administration, and the pharmaceutical compositions of the present invention may be prepared in the form of solutions, for example, by a conventional method using physiological saline or an aqueous solution containing glucose and other adjuvants. The pharmaceutical composition is preferably manufactured under sterile conditions. The amount of active ingredient administered is a therapeutically effective amount.

The effective amount of the antibody-drug conjugate of the present invention may vary depending on the mode of administration and the severity of the disease to be treated, etc. The selection of a preferred effective amount can be determined by one of ordinary skill in the art based on a variety of factors (e.g., by clinical trials). Such factors include, but are not limited to: pharmacokinetic parameters of the antibody conjugate such as bioavailability, metabolism, half-life, etc.; the severity of the disease to be treated by the patient, the weight of the patient, the immune status of the patient, the route of administration, and the like. In general, satisfactory results are obtained when the antibody-drug conjugate of the present invention is administered at a daily dose of about 0.0001mg to 50mg/kg of animal body weight, preferably 0.001mg to 10mg/kg of animal body weight. For example, divided doses may be administered several times per day, or the dose may be proportionally reduced, as may be required by the urgency of the condition being treated.

Dosage forms for topical administration of the compounds of the present invention include ointments, powders, patches, sprays, and inhalants. The active ingredient is mixed under sterile conditions with a physiologically acceptable carrier and any preservatives, buffers, or propellants which may be required if necessary.

The compounds of the present invention may be administered alone or in combination with other pharmaceutically acceptable therapeutic agents.

When the pharmaceutical composition is used, a safe and effective amount of the antibody conjugate of the present invention is applied to a mammal (e.g., human) in need of treatment, wherein the administration dose is a pharmaceutically acceptable effective administration dose, and for a human with a weight of 60kg, the daily administration dose is usually 1 to 2000mg, preferably 5 to 500 mg. Of course, the particular dosage will depend upon such factors as the route of administration, the health of the patient, and the like, and is within the skill of the skilled practitioner.

The main advantages of the invention

(1) The novel linker provided by the invention can be coupled with a targeting CD73 antibody by a simple chemical method, compared with the traditional coupling mode, the DAR value distribution of the CD73 antibody drug conjugate obtained by applying the linker is very narrow, so that the generated product has high uniformity, and the obtained single-distribution component (DAR is 4) of the cross-linked product accounts for more than 80%.

(2) The ratio of naked antibody to low-crosslinking ADC of the CD73 antibody drug conjugate provided by the invention is almost zero (components with DAR of 0 and 1 can not be detected by mass spectrometry).

(3) the applicant proves through a large number of experiments that the CD73 antibody drug conjugate provided by the invention has certain safety and effectiveness in the aspect of treating tumors. The hydrophilicity conferred by the ethylene glycol after coupling can be used to modulate biomolecular properties; the in vitro tumor cell proliferation inhibiting activity of the cross-linked product is improved or maintained in comparison with the traditional mcVC-PAB cross-linked biological activity, drug metabolic stability, safety and other drug properties.

(4) Compared with the existing coupling method, the advantages of the disulfide chain bridging crosslinking reagent based on the maleimide provided by the invention comprise: has a fast crosslinking speed, and the crosslinking reaction time can be finished within 2-4 hours.

The following specific examples further illustrate the invention. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental procedures, for which specific conditions are not indicated in the following examples, are generally carried out according to conventional conditions, for example as described in Sambrook and Russell et al, Molecular Cloning: A laboratory Manual (third edition) (2001) CSHL Press, or according to the conditions as recommended by the manufacturer. Unless otherwise indicated, percentages and parts are by weight. Unless otherwise indicated, percentages and parts are by weight. The test materials and reagents used in the following examples are commercially available without specific reference.

Before the present invention is described, it is to be understood that this invention is not limited to the particular methodology and experimental conditions described, as such methodologies and conditions may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the methods and materials are now described.

Example 1 Synthesis and preparation of Compounds of formula Ic

the substituted maleimide linker fragment molecules represented by formula Ia listed in the first aspect of the present invention may be synthesized by the method of scheme one, by reacting n-glycol with t-butyl bromoacetate to obtain intermediate a, followed by aromatic nucleophilic substitution with substituted nitrofluorobenzene to obtain intermediate B. Alternatively, intermediate B may be obtained by reacting p-toluenesulfonate-protected intermediate F with a substituted nitrofluorophenol. Reducing the nitro group in the intermediate B into amino to obtain an intermediate C, performing cyclization reaction with 2, 3-dibromo maleic anhydride to obtain an intermediate D, and performing substitution reaction with aryl thiophenol to obtain a linker fragment molecule E. The series of molecules F can be obtained by condensation with a linker carrying a dipeptide/tripeptide-PAB cytotoxic drug. The reaction scheme and specific examples are illustrated below:

1.1 Synthesis of Compound Ic-1

1.1.1 intermediate A-1 (step a)

Triethylene glycol (92g,613mmol) was dissolved in tBuOH (200 ml). KOtBu (22.91g,204mmol) was added to the ice bath and stirred for half an hour, and under argon, a solution of t-butyl bromoacetate (39.8g,204mmol) in tBuOH (40ml) was added dropwise and stirred at room temperature overnight. The next day, the reaction was completed by TLC. After removal of the tert-butanol by rotary evaporation, 400ml of dichloromethane were added to the residue, the organic phase was washed with 400ml of water, the aqueous phase was extracted once with 300ml of dichloromethane, the organic phases were combined and washed once with saturated salt, dried over anhydrous sodium sulfate and evaporated to dryness by rotary evaporation. The crude product was purified by petroleum ether: column chromatography in ethyl acetate 3:1 ═ 1:1 afforded intermediate a-1(24g, 44.5% yield) as a yellow oil.

1.1.2 intermediate B-1 (step B)

Intermediate A-1(4g,15.13mmol), triethylamine (2.53ml,18.16mmol) and dimethylaminopyridine (0.370g,3.03mmol) were dissolved in 100ml molecular sieve dried dichloromethane in a 250ml round-bottom flask and stirred, p-toluenesulfonyl chloride (3.17g,16.65mmol) was added portionwise under ice bath and stirred overnight at room temperature under argon atmosphere.

the reaction system was extracted with 100ml of dichloromethane, washed once with 200ml of 1N dilute hydrochloric acid, twice with 200ml of water, once with 200ml of saturated brine, dried over anhydrous sodium sulfate and the organic phase evaporated to dryness by rotary evaporation. Loading the column with 200-mesh 300-mesh silica gel, and eluting with PE and EA at a ratio of 5:1-2:1 to perform column chromatography separation. This was evaporated to dryness to give intermediate B-1(2.8g, yield 44.2%).

1.1.3 intermediate C-1 (step C)

intermediate B-1(3g,7.19mmol), 4-nitrophenol (1g,7.19mmol) were dissolved in 20ml DMF and K was added₂CO₃(1.9g,14.4mmol), heated to 100 ℃ and stirred for 5 hours. Evaporating the solvent by rotary evaporation, adding 200ml of dichloromethane for dissolution, extracting, washing with 200ml of 1N diluted hydrochloric acid, 200ml of water and 200ml of saturated saline respectively once, drying with anhydrous sodium sulfate, evaporating by rotary evaporation, packing with 200-mesh 300-mesh silica gel, and performing PE: and (3) carrying out column chromatography purification by eluting with 5:1-3:1, and evaporating to dryness to obtain an intermediate C-1(2g, yield 72%).

1.1.4 intermediate D-1 (step D)

Intermediate B-1(6g,15.57mmol) was dissolved in 100ml of absolute ethanol and the solution was added to a reaction flask containing 1.2g of 10% Pd-C. Hydrogenation reaction for 6 hours (1atm,38 ℃), TLC detection reaction complete. The reaction solution was filtered through celite, the filter cake was rinsed with ethanol, and the filtrate was rotary evaporated to dryness to give intermediate D-1(4.8g, 87% yield) as a yellow oil.

1.1.5 Compound E-1 (step E)

Intermediate D-1(1.0g,2.81mmol) was weighed into a parallel reaction tube, AcOH (3ml) was added under nitrogen protection, and dissolved with stirring. Then 3, 4-dibromomaleic anhydride (0.72g,2.81mmol) was added slowly. The mixture was heated to 110 ℃ under nitrogen and stirred overnight. The reaction was checked by TLC. And cooling the reaction solution to room temperature, evaporating the solvent by rotary evaporation, adding toluene, and evaporating by rotary evaporation twice to obtain a brown oily compound E-1. The product was used in the next reaction without purification.

1.1.6 Synthesis of Compound F-1 (step F)

Compound E-1(2.0g,3.72mmol) was weighed into a 100ml round-bottomed flask, and dissolved by adding 30ml of anhydrous dichloromethane under nitrogen protection with stirring. Weighing 4- (N-morpholine formamide) thiophenol (1.66g,7.45mmol) and adding into the reaction solution under the protection of nitrogen, after dissolving, slowly dropping DIPEA (1.3mL, 7.45mmol) under ice bath, stirring for 5 minutes after completion, and removing the ice bath. The mixture was stirred at room temperature for 2 hours under nitrogen protection, and the reaction was completed by TLC.

And (3) after the solvent is evaporated to dryness under reduced pressure, performing column chromatography (200-300 meshes of silica gel) for separation and purification, loading and leaching dichloromethane, then slowly increasing the polarity, leaching from 2% to 10% of methanol, and collecting the evaporated solvent to obtain an orange oily product F-1(2.2g, 72% yield). LC-MS (M)⁺) Theoretical value 821.2, found value 821.3(ESI, M + H)⁺)。

1.1.7 Synthesis of Compound G-1(Ic-1) (step G)

Compound E-9(300mg,0.365mmol) was weighed into a 100mL round bottom flask, and after complete dissolution by addition of anhydrous DMF (20mL) under nitrogen, HATU (166mg,0.438mmol) and DIEA (0.127mL,0.730mmol) were weighed into the flask in that order. After stirring at room temperature for 15 min, the compound VC-PAB-MMAE (416mg,0.365mmol) was added and stirred at room temperature overnight under nitrogen. TLC followed by HPLC overnight and starting material F-1 disappeared. The solvent was evaporated under reduced pressure for quantitative analysis and purified by reverse phase HPLC to give the product as yellow amorphous powder G-1(0.420G, 59.7% yield). LC-MS (M +) theoretical 1925.9, found 1926.7(ESI, M + H +).

1.2 Synthesis of Compound Ic-2

Synthesis of Compound Ic-2 the same procedure was followed as for Compound Ic-1 in example 1.1, except that 4-nitrophenol in step c was replaced by 2, 6-difluoro-4-nitrophenol to give product Ic-2 as a yellow amorphous powder. LC-MS (M)⁺) Theoretical value 1961.9, found value 1962.7(ESI, M + H)⁺)。

1.3 Synthesis of Compound Ic-3

synthesis of Compound Ic-3 the same procedure was followed as for Compound Ic-1 in example 1.1, except that 4-nitrophenol and 4- (N-morpholinocarboxamide) thiophenol in steps c and f were replaced with 2, 6-difluoro-4-nitrophenol and 4- (1, 1-thiomorpholinecarboxamide) thiophenol, respectively, to give product Ic-3 as a yellow amorphous powder. LC-MS (M)⁺) Theoretical value 2057.8, found value 2058.8(ESI, M + H)⁺)。

1.4 Synthesis of Compound Ic-4

Synthesis of Compound Ic-4 the same procedure was followed as for Compound Ic-1 in example 1.1, except that 4-nitrophenol in step c was replaced by 2-trifluoromethyl-4-nitrophenol to give product Ic-4 as a yellow amorphous powder.

LC-MS(M⁺) Theoretical value 1993.9, found value 1994.9(ESI, M + H)⁺)。

1.5 Synthesis of Compound Ic-5

Synthesis of Compound Ic-5 the same procedure was followed as for Compound Ic-1 in example 1.1, except that triethylene glycol in step a was replaced by hexaethylene glycol to give product Ic-5 as a yellow amorphous powder. LC-MS (M)⁺) Theoretical value 2093.9, found value 2094.0(ESI, M + H)⁺)。

1.6 Synthesis of Compound Ic-6

Synthesis of Compound Ic-6 the same procedure was followed as for Compound Ic-1 in example 1.1, except that 4-nitrophenol in step c was replaced by 3-trifluoromethyl-4-nitrophenol to give product Ic-6 as a yellow amorphous powder. LC-MS (M)⁺) Theoretical value 1993.9, found value 1994.7(ESI, M + H)⁺)。

1.7 Synthesis of Compound Ic-7

Synthesis of Compound Ic-7 the same procedure was followed as for Compound Ic-1 in example 1.1, except that 4-nitrophenol and VC-PAB-MMAE in step c and step g were replaced by 2, 6-difluoro-4-nitrophenol and VC-PAB-MMAF to give the product Ic-7 as a yellow amorphous powder. LC-MS (M)⁺) Theoretical value 1989.9, found value 1990.9(ESI, M + H)⁺)。

Example 2 preparation of antibody conjugates

2.1 preparation of MEDI9447-ADC2

Replacement of CD 73-targeting humanized antibody MEDI9447 stock solution to 50mM sodium dihydrogen phosphate-disodium hydrogen phosphate (NaH)₂PO₄-Na₂HPO₄) To a reaction buffer solution of 150mM sodium chloride (NaCl)/2mM ethylenediaminetetraacetic acid (EDTA) at pH 7.0 so that the concentration thereof was 10mg/mL, tris (2-carboxyethyl) phosphine hydrochloride (TCEP) was added in a 10-fold excess molar ratio, and the reaction solution was stirred at 25 ℃ for 4 hours.

the reaction solution is cooled to 20 ℃, a proper amount of diethyl acetamide (DMA) is added, then compound Ic-2 with 6 times of excessive molar ratio (10mg/ml is dissolved in DMA in advance) is added, the volume of DMA in the reaction system is ensured not to exceed 10%, and the coupling is carried out by stirring for 2.0 hours at 20 ℃.

The coupling reaction mixture was purified by filtration through a desalting column using Tris-HCl/sucrose gel pH 7.5, and peak samples were collected according to UV280 UV absorbance. The antibody conjugate was then sterilized through a 0.22 micron pore size filter unit and stored at-80 ℃ and designated MEDI9447-ADC 2.

The results are shown in fig. 2,3 and 5. Both HIC and mass spectra showed that after conjugation, antibody conjugate MEDI9447-ADC2 was formed, with a molecular weight consistent with the expected value and a DAR value of approximately 4.0.

the preparation of antibody conjugates MEDI9447-ADC1, MEDI9447-ADC3, MEDI9447-ADC4, MEDI9447-ADC5, MEDI9447-ADC6 was identical to the preparation of example 2.1MEDI9447-ADC2, except that compound Ic-2 or 3 was replaced with the corresponding compound of formula Ic. Specifically, compound Ic-1 is substituted for compound Ic-2 or 3 to prepare MEDI9447-ADC 1; replacing compound Ic-2 or 3 with compound Ic-4 to obtain MEDI9447-ADC 3; replacing compound Ic-2 or 3 with compound Ic-6 to obtain MEDI9447-ADC 4; replacing compound Ic-2 or 3 with compound Ic-5 to obtain MEDI9447-ADC 5; MEDI9447-ADC6 was prepared by substituting compound Ic-7 for compound Ic-2 or 3.

2.2 preparation of MEDI9447-vcMMAE

PBS/EDTA (pH 7.4) buffer was added to a stock solution of humanized antibody MEDI9447 targeting CD73 to give a concentration of 20mg/ml, and then reduced with 2.6eq of TCEP at 25 ℃ for 2 hours, taken out and cooled on ice, 6.0eq of mc-VC-PAB-MMAE (available from Shanghai Haoyuan chemical) was added without purification, and the reaction was stopped by adding cysteine at 0 ℃ for 1 hour. Excess small molecules were removed using a G25 desalting column and replaced in 20mM citric acid-sodium citrate/6% sucrose, pH 6.6 buffer, sterilized by a 0.22 micron pore size filter unit and stored at-80 ℃ and the resulting antibody conjugate was designated MEDI 9447-vcMAE.

The results are shown in FIGS. 1, 3 and 4. Both HIC and mass spectra showed that after the conjugation reaction, antibody conjugate MEDI9447-vcMMAE was formed, the molecular weight of the conjugate was consistent with the expected value, and the average DAR value was about 4.0.

Example 3 detection of biological Activity of antibody conjugates

The cell lines used in this example were purchased from the American Type Culture Collection (ATCC) or cell bank of national academy of sciences and cultured according to the corresponding instructions, including: tumor cells highly expressed in CD73, such as: u87MG, Calu-1, Calu-6, NCI-H441, NCI-H292, and tumor cells MDA-MB-453 with low expression of CD73 (negative control).

The cells in logarithmic growth phase are inoculated into 96-well cell culture plates at a density of 1,000-3,000 cells per well (according to the growth rate of different cells), after culturing at a temperature of 37 ℃ and 5% CO2 for about 16h, different concentrations of MEDI9447-vcMMAE and MEDI9447-ADC2 are added, 3 multiple wells are set for each drug concentration, and corresponding vehicle control and blank control wells, after 6 days, the culture solution is poured out, MTS reaction solution (purchased from Promega, cat # G3581) and 100 μ L/well are added, the reaction is carried out at 37 ℃ to the expected color depth, the cell viability (OD490nm) of each group is determined, and the cell viability is calculated according to the following formula:

Survival rate was (OD dose-OD blank)/(OD control-OD blank) × 100%.

The data were analyzed by GraphPad Prism 5 software and the IC's of MEDI9447-vcMMAE, MEDI9447-ADC2 on different cell lines were calculated₅₀The value is obtained.

The experimental results (FIG. 6, FIG. 7, FIG. 8, FIG. 9, FIG. 10) show that MEDI 9447-vcMAE and MEDI9447-ADC2 can both better inhibit the growth of tumor cells with high CD73 expression in vitro, and the IC of MEDI9447-ADC2 on different cell lines₅₀Lower values relative to MEDI9447-vcMMAE values; whereas the effect was weaker on tumor cells with low expression of CD73 (FIG. 11), since IC₅₀The curves show that MEDI9447-ADC2 may have better stability than MEDI9447-vcMMAE, resulting in less nonspecific release of toxicants with less negative cell impact.

All documents referred to herein are incorporated by reference into this application as if each were individually incorporated by reference. Furthermore, it should be understood that various changes and modifications of the present invention can be made by those skilled in the art after reading the above teachings of the present invention, and these equivalents also fall within the scope of the present invention as defined by the appended claims.

Sequence listing

<110> Shanghai pharmaceutical research institute of Chinese academy of sciences

<120> antibody-drug conjugate targeting CD73, and preparation method and application thereof

<130> P2018-0864

<160> 2

<170> PatentIn version 3.5

<210> 1

<211> 447

<212> PRT

<213> Artificial sequence (Artificial sequence)

<400> 1

Glu Val Gln Leu Leu Glu Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Phe Thr Phe Ser Ser Tyr

20 25 30

Ala Tyr Ser Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu Trp Val

35 40 45

Ser Ala Ile Ser Gly Ser Gly Gly Arg Thr Tyr Tyr Ala Asp Ser Val

50 55 60

Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Asn Thr Leu Tyr

65 70 75 80

Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr Tyr Cys

85 90 95

Ala Arg Leu Gly Tyr Gly Arg Val Asp Glu Trp Gly Arg Gly Thr Leu

100 105 110

Val Thr Val Ser Ser Ala Ser Thr Lys Gly Pro Ser Val Phe Pro Leu

115 120 125

Ala Pro Ser Ser Lys Ser Thr Ser Gly Gly Thr Ala Ala Leu Gly Cys

130 135 140

Leu Val Lys Asp Tyr Phe Pro Glu Pro Val Thr Val Ser Trp Asn Ser

145 150 155 160

Gly Ala Leu Thr Ser Gly Val His Thr Phe Pro Ala Val Leu Gln Ser

165 170 175

Ser Gly Leu Tyr Ser Leu Ser Ser Val Val Thr Val Pro Ser Ser Ser

180 185 190

Leu Gly Thr Gln Thr Tyr Ile Cys Asn Val Asn His Lys Pro Ser Asn

195 200 205

Thr Lys Val Asp Lys Arg Val Glu Pro Lys Ser Cys Asp Lys Thr His

210 215 220

Thr Cys Pro Pro Cys Pro Ala Pro Glu Phe Glu Gly Gly Pro Ser Val

225 230 235 240

Phe Leu Phe Pro Pro Lys Pro Lys Asp Thr Leu Met Ile Ser Arg Thr

245 250 255

Pro Glu Val Thr Cys Val Val Val Asp Val Ser His Glu Asp Pro Glu

260 265 270

Val Lys Phe Asn Trp Tyr Val Asp Gly Val Glu Val His Asn Ala Lys

275 280 285

Thr Lys Pro Arg Glu Glu Gln Tyr Asn Ser Thr Tyr Arg Val Val Ser

290 295 300

Val Leu Thr Val Leu His Gln Asp Trp Leu Asn Gly Lys Glu Tyr Lys

305 310 315 320

Cys Lys Val Ser Asn Lys Ala Leu Pro Ala Ser Ile Glu Lys Thr Ile

325 330 335

Ser Lys Ala Lys Gly Gln Pro Arg Glu Pro Gln Val Tyr Thr Leu Pro

340 345 350

Pro Ser Arg Glu Glu Met Thr Lys Asn Gln Val Ser Leu Thr Cys Leu

355 360 365

Val Lys Gly Phe Tyr Pro Ser Asp Ile Ala Val Glu Trp Glu Ser Asn

370 375 380

Gly Gln Pro Glu Asn Asn Tyr Lys Thr Thr Pro Pro Val Leu Asp Ser

385 390 395 400

Asp Gly Ser Phe Phe Leu Tyr Ser Lys Leu Thr Val Asp Lys Ser Arg

405 410 415

Trp Gln Gln Gly Asn Val Phe Ser Cys Ser Val Met His Glu Ala Leu

420 425 430

His Asn His Tyr Thr Gln Lys Ser Leu Ser Leu Ser Pro Gly Lys

435 440 445

<210> 2

<211> 216

<212> PRT

<213> Artificial sequence (Artificial sequence)

<400> 2

Gln Ser Val Leu Thr Gln Pro Pro Ser Ala Ser Gly Thr Pro Gly Gln

1 5 10 15

Arg Val Thr Ile Ser Cys Ser Gly Ser Leu Ser Asn Ile Gly Arg Asn

20 25 30

Pro Val Asn Trp Tyr Gln Gln Leu Pro Gly Thr Ala Pro Lys Leu Leu

35 40 45

Ile Tyr Leu Asp Asn Leu Arg Leu Ser Gly Val Pro Asp Arg Phe Ser

50 55 60

Gly Ser Lys Ser Gly Thr Ser Ala Ser Leu Ala Ile Ser Gly Leu Gln

65 70 75 80

Ser Glu Asp Glu Ala Asp Tyr Tyr Cys Ala Thr Trp Asp Asp Ser His

85 90 95

Pro Gly Trp Thr Phe Gly Gly Gly Thr Lys Leu Thr Val Leu Gly Gln

100 105 110

Pro Lys Ala Ala Pro Ser Val Thr Leu Phe Pro Pro Ser Ser Glu Glu

115 120 125

Leu Gln Ala Asn Lys Ala Thr Leu Val Cys Leu Ile Ser Asp Phe Tyr

130 135 140

Pro Gly Ala Val Thr Val Ala Trp Lys Ala Asp Ser Ser Pro Val Lys

145 150 155 160

Ala Gly Val Glu Thr Thr Thr Pro Ser Lys Gln Ser Asn Asn Lys Tyr

165 170 175

Ala Ala Ser Ser Tyr Leu Ser Leu Thr Pro Glu Gln Trp Lys Ser His

180 185 190

Arg Ser Tyr Ser Cys Gln Val Thr His Glu Gly Ser Thr Val Glu Lys

195 200 205

Thr Val Ala Pro Thr Glu Cys Ser

210 215

Claims

1. a closed or open-loop maleimide-based antibody-drug conjugate, wherein said conjugate has a structure according to formula Ia and/or Ib;

Wherein the content of the first and second substances,

The antibody (Ab) is an antibody or antibody fragment that targets CD 73.

2. The antibody-drug conjugate of claim 1, wherein the closed or open-loop maleimide group is attached to a thiol group of the antibody hinge region after disulfide chain reduction.

3. the antibody-drug conjugate of claim 1, wherein the closed or open-ring maleimide group is attached to the fully reduced antibody such that the 4-disulfide bond of the hinge region is fully open, preferably m is from 3.8 to 4.2, more preferably from 3.9 to 4.1, most preferably 4.0.

4. the antibody-drug conjugate of claim 1, wherein the CD 73-targeting antibody is selected from the group consisting of: monoclonal antibodies, bispecific antibodies, chimeric antibodies, humanized antibodies, antibody fragments (preferably antibody Fab fragments).

5. The antibody-drug conjugate of claim 1, wherein the CD 73-targeting antibody is the clinical in-study drug MEDI 9447.

6. the antibody-drug conjugate of claim 1, wherein Ar' is selected from the group consisting of substituted or unsubstituted phenylene or pyridyl, and wherein said substitution is a substitution of a hydrogen atom on a group with one or more substituents selected from the group consisting of: halogen, C1-C4 alkyl, C1-C4 alkoxy, trifluoromethyl, nitrile group and amide group.

7. The antibody-drug conjugate of claim 1, wherein the AA is selected from the group consisting of: Val-Cit (valine-citrulline), Val-Ala (valine-alanine), Phe-Lys (phenylalanine-lysine), Ala-Ala-Asn (alanine-asparagine), D-Ala-Phe-Lys (alanine-phenylalanine-lysine D), Gly-Gly-Phe-Gly (glycine-phenylalanine-glycine).

8. the antibody-drug conjugate of claim 1, wherein the CTD is a cytotoxic small molecule drug selected from the group consisting of: tubulin inhibitors, topoisomerase inhibitors, DNA binding agents.

9. The antibody-drug conjugate of claim 8, wherein the tubulin inhibitor is selected from the group consisting of: maytansine (maytansine) derivatives, Monomethylauristatin E (MMAE), Monomethylauristatin F (MMAF), monomethylolastin 10, Tubulysin derivatives, Cryptophycin derivatives, Taltobulin, or combinations thereof.

10. the antibody-drug conjugate of claim 8, wherein the topoisomerase inhibitor is selected from the group consisting of: doxorubicin (Doxorubicin) metabolite PNU-159682 derivative, irinotecan (Exatecan, DX8951), irinotecan (CPT-11) metabolite SN38 derivative.

11. The antibody-drug conjugate of claim 8, wherein the DNA binding agent is selected from the group consisting of: a PBD-like derivative, a duocarmycin-like derivative, or a combination thereof.

12. The antibody-drug conjugate of any one of claims 1 to 11, wherein the antibody-drug conjugate (ADC) is selected from the group consisting of:

Conjugate ADC1 was structurally as follows:

Conjugate ADC2 was structurally as follows:

Conjugate ADC3 was structurally as follows:

Conjugate ADC4 was structurally as follows:

Conjugate ADC5 was structurally as follows:

Conjugate ADC6 was structurally as follows:

13. a pharmaceutical composition comprising:

(i) An active ingredient which is the antibody drug conjugate of any one of claims 1-12, or a pharmaceutically acceptable salt or solvate thereof, or a combination thereof; and

(ii) A pharmaceutically acceptable diluent, carrier (vehicle) and/or excipient.

14. Use of an antibody-drug conjugate according to any one of claims 1 to 12 for the preparation of a medicament for the treatment of a tumour, wherein the tumour is a CD73 mediated tumour.

15. The use of claim 15, wherein the CD 73-mediated tumor is selected from the group consisting of: colorectal cancer, pancreatic cancer, bladder cancer, leukemia, lymphoma, glioma, glioblastoma, melanoma (e.g., malignant melanoma), ovarian cancer, thyroid cancer, esophageal cancer, prostate cancer, breast cancer, liver cancer, non-small cell lung cancer, squamous cell carcinoma, renal cell carcinoma, gastrointestinal tumors, gastric cancer, mesothelioma.

16. a method for preparing an antibody-drug conjugate according to any one of claims 1 to 12, comprising the steps of: