Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K16/00—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies
  • C07K16/18—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans
  • C07K16/28—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants
  • C07K16/2803—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against the immunoglobulin superfamily
• • A—HUMAN NECESSITIES
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  • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
  • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
  • A61K47/68—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment
  • A61K47/6801—Drug-antibody or immunoglobulin conjugates defined by the pharmacologically or therapeutically active agent
  • A61K47/6803—Drugs conjugated to an antibody or immunoglobulin, e.g. cisplatin-antibody conjugates
  • A61K47/68037—Drugs conjugated to an antibody or immunoglobulin, e.g. cisplatin-antibody conjugates the drug being a camptothecin [CPT] or derivatives
• • A—HUMAN NECESSITIES
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  • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
  • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
  • A61K47/68—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment
  • A61K47/6835—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site
  • A61K47/6839—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site the antibody targeting material from viruses
  • A61K47/6841—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site the antibody targeting material from viruses the antibody targeting a RNA virus
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
  • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
  • A61K47/68—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment
  • A61K47/6835—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site
  • A61K47/6849—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site the antibody targeting a receptor, a cell surface antigen or a cell surface determinant
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
  • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
  • A61K47/68—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment
  • A61K47/6889—Conjugates wherein the antibody being the modifying agent and wherein the linker, binder or spacer confers particular properties to the conjugates, e.g. peptidic enzyme-labile linkers or acid-labile linkers, providing for an acid-labile immuno conjugate wherein the drug may be released from its antibody conjugated part in an acidic, e.g. tumoural or environment
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P25/00—Drugs for disorders of the nervous system
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/04—Antibacterial agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/12—Antivirals
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P33/00—Antiparasitic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P37/00—Drugs for immunological or allergic disorders
  • A61P37/02—Immunomodulators
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K16/00—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies
  • C07K16/08—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from viruses
  • C07K16/10—RNA viruses
  • C07K16/112—Retroviridae (F), e.g. leukemia viruses
  • C07K16/114—Lentivirus (G), e.g. human immunodeficiency virus [HIV], feline immunodeficiency virus [FIV] or simian immunodeficiency virus [SIV]
  • C07K16/1145—Env proteins, e.g. gp41, gp110/120, gp160, V3, principal neutralising domain [PND] or CD4-binding site
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K16/00—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies
  • C07K16/18—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans
  • C07K16/28—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants
  • C07K16/2803—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against the immunoglobulin superfamily
  • C07K16/2833—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against the immunoglobulin superfamily against MHC-molecules, e.g. HLA-molecules
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K16/00—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies
  • C07K16/18—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans
  • C07K16/28—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants
  • C07K16/2863—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against receptors for growth factors, growth regulators
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K16/00—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies
  • C07K16/18—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans
  • C07K16/28—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants
  • C07K16/30—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants from tumour cells
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K2039/505—Medicinal preparations containing antigens or antibodies comprising antibodies
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/70—Immunoglobulins specific features characterized by effect upon binding to a cell or to an antigen
  • C07K2317/76—Antagonist effect on antigen, e.g. neutralization or inhibition of binding

Definitions

• the present invention relates to therapeutic conjugates with improved ability to target various cancer cells, infectious disease organisms and/or for treating autoimmune diseases, which conjugates contain a targeting (binding) moiety and a therapeutic moiety belonging to the camptothecin group of drugs.
• the targeting and therapeutic moieties are linked via an intracellular Iy cleavable linkage that increases therapeutic efficacy.
• MAbs monoclonal antibodies
• the advantages of using MAb-chemotherapy drug conjugates are that (a) the chemotherapy drug itself is structurally well defined; (b) the chemotherapy drug is linked to the MAb protein using very well defined conjugation chemistries, often at specific sites remote from the MAbs antigen binding regions; (c) MAb-chemotherapy drug conjugates can be made more reproducibly than chemical conjugates involving MAbs and bacterial or plant toxins, and as such are more amenable to commercial development and regulatory approval; and (d) the MAb-chemotherapy drug conjugates are orders of magnitude less toxic systemically than radionuclide MAb conjugates. [0005] The present disclosure solves specific problems associated with the preparation of conjugates of the camptothecin (CPT) group of cytotoxic compounds.
• CPT camptothecin
• CPT and its derivatives are a class of potent antitumor agents.
• Irinotecan also referred to as CPT-11
• topotecan are CPT analogs that are approved cancer therapeutics (Iyer and Ratain, Cancer Chemother. Phamacol. 42: S31-S43 (1998)).
• CPTs act by inhibiting topoisomerase I enzyme by stabilizing topoisomerase I-DNA complex (Liu, et al. in The Camptothecins: Unfolding Their Anticancer Potential, Liehr J.G., Giovanella, B.C. and Verschraegen (eds), NY Acad Sci., NY 922:1-10 (2000)).
• CPTs present a set of caveats in the preparation of conjugates.
• One caveat is the insolubility of most CPT derivatives in aqueous buffers.
• CPTs provide specific challenges for structural modification for conjugating to macromolecules. For instance, CPT itself contains only a tertiary hydro xyl group in ring-E.
• the hydroxyl functional group in the case of CPT must be coupled to a linker suitable for subsequent protein conjugation; and in potent CPT derivatives, such as SN-38, the active metabolite of the chemotherapeutic CPT- 11, and other C-10-hydroxyl-containing derivatives such as topotecan and 10-hydroxy-CPT, the presence of phenolic hydroxyl at C-10 position complicates the necessary C-20-hydroxyl derivatization.
• the conjugation protocol is performed such that it is carried out at a pH of 7 or lower to avoid the lactone ring opening.
• an intracellularly-cleavable moiety is to be incorporated in the linker/spacer connecting the CPTs and the antibodies or other binding moieties.
• This glycine conjugation has also been reported as a method of making water-soluble derivative of CPT (Vishnuvajjala et al., U.S. Patent No. 4,943,579) and in the preparation of a PEG-derivatization of CPT (Greenwald, et al. J. Med. Chem. 39: 1938-1940 (1996).
• the approach has been devised in the context of developing water-soluble and long acting forms of CPT, whereby CPT's in vivo half-life is enhanced, and the drug is gradually released from its conjugate while in circulation in vivo.
• the present invention discloses methods for preparing conjugates of CPTs, of 10- hydroxy derivatives such as SN-38 in particular, taking into consideration the four caveats described above and the synthetic challenges.
• SN-38 is the active drug form of the approved cancer drug CPT-11, which is a prodrug.
• Vast clinical data are available concerning CPT-11 pharmacology and of its in vivo conversion to SN-38 (Iyer and Ratain, supra; Mathijssen et al, Clin Cancer Res. 7:2182-2194 (2002); Rivory, Ann NY Acad ScL 922:205-215, 2000)).
• the active form SN-38 is about 2 to 3 orders of magnitude more potent than CPT-11.
• MAb-doxorubicin (DOX) conjugates prepared with appropriate linkers, could be used to cure mice bearing a variety of human tumor xenografts, in preclinical studies.
• the first approved MAb-drug conjugate, Gemtuzumab Ozogamicin incorporates a similar acid-labile hydrazone bond between an anti-CD33 antibody, humanized P67.6, and a potent calicheamicin derivative.
• the MAb-chemotherapy drug conjugates were made with reductively labile hindered disulfide bonds between the chemotherapy drugs and the MAb (Liu et al, Proc Natl Acad Sci USA 93: 8618-8623 (1996)).
• Yet another cleavable linker involves a cathepsin B- labile dipeptide spacers, such as Phe-Lys or Val-Cit, similar to the lysosomally labile peptide spacers of Trouet et al. containing from one to four amino acids, which additionally incorporated a collapsible spacer between the drug and the dipeptide (Dubowchik, et al., Bioconjugate Chem.
• the present invention solves the problem associated with the preparation of the bifunctional drug-linker molecule, wherein the said drug may also contain more than one reactive group for derivatization, such as the potent SN-38 analog, for instance, in the design of conjugates.
• the potent SN-38 analog for instance, in the design of conjugates.
• SN- 38 a clinically important active drug form of the cancer drug CPT-11, but 100-1000-times more potent than CPT-11, is not useable systemically because of insolubility.
• the present invention solves this problem by conjugating it to a targeting moiety in ways that also address other challenges of using a CPT, while concurrently improving the therapeutic index of this clinically important potent drug by using disease-specific antibodies.
• the conjugates of the instant invention possess greater efficacy, in many cases, than unconjugated or "naked” antibodies or antibody fragments, although such unconjugated targeting molecules have been of use in specific situations.
• naked antibodies have come to play a role in the treatment of lymphomas (Campath® and Rituxan®), colorectal and other cancers (Erbitux® and Avastin®), breast cancer
• epratuzumab a large number now in clinical development
• epratuzumab a large number now in clinical development
• a variety of antibodies are also in use for the treatment of autoimmune and other immune dysregulatory diseases, such as tumor necrosis factor (TNF) and B-cell (Rituxan®) antibodies in arthritis, and are being investigated in other such diseases, such as the B-cell antibodies Rituxan® and epratuzumab in systemic lupus erythematosus and Sjogren's syndrome, as well as juvenile diabetes and multiple sclerosis.
• TNF tumor necrosis factor
• Rituxan® B-cell antibodies
• Naked antibodies are also being studied in sepsis and septic shock, Alzheimer's disease, and infectious diseases.
• the development of anti- infective monoclonal antibodies has been reviewed recently by Reichert and Dewitz (Nat Rev Drug Discovery 2006; 5:191-195), incorporated herein by reference, which summarizes the priority pathogens against which naked antibody therapy has been pursued, resulting in only 2 pathogens against which antibodies are either in Phase III clinical trials or are being marketed (respiratory syncytial virus and methicillin-resistant Staphylococcus aureus), with 25 others in clinical studies and 20 discontinued during clinical study.
• the present invention resolves an unfulfilled need in the art by providing improved methods and compositions for preparation of camptothecin-binding moiety conjugates.
• the disclosed methods and compositions are of use for the treatment of a variety of diseases and conditions which are refractory or less responsive to other forms of therapy, and can include diseases against which suitable targeting moieties for selective targeting can be developed, or are available or known.
• this targeting moiety is an antibody, antibody fragment, bispecific or other multivalent antibody, or other antibody-based molecule or compound.
• binding moieties known in the art such as aptamers, avimers or targeting peptides, may be used.
• Preferred diseases or conditions against which such targeting moieties exist are, for example, cancer, immune dysregulatory conditions, including autoimmune diseases and inflammatory diseases, diseases caused by infectious organisms, neurodegenerative diseases (e.g., Alzheimer's diseases), and cardiovascular diseases (fibrin clots, atherosclerosis, myocardial iscehmia and infarcts).
• autoimmune diseases and inflammatory diseases diseases caused by infectious organisms
• neurodegenerative diseases e.g., Alzheimer's diseases
• cardiovascular diseases fibrin clots, atherosclerosis, myocardial iscehmia and infarcts.
• the disclosed methods and compositions may thus be applied for treatment of diseases and conditions for which targeting moieties are of use to deliver camptothecin- related cytotoxic agents.
• diseases or conditions may be characterized by the presence of a target molecule or target cell that is insufficiently affected when unconjugated, or naked, targeting moieties are used, such as in the immunotherapy of cancer or of infection with pathogenic organisms.
• targeting moieties are used, such as in the immunotherapy of cancer or of infection with pathogenic organisms.
• camptothecin conjugates of antibodies or antibody fragments may be used for targeting this therapeutic drug to pathogens, such as bacteria, viruses, fungi, and parasites.
• pathogens such as bacteria, viruses, fungi, and parasites.
• drug-conjugated targeting moieties can be used in combination with other therapeutic modalities, such as anti- fungal, antibiotics and anti-viral drugs and/or naked antibodies, immunomodulators (e.g., interferon and/or cytokines).
• immunomodulators e.g., interferon and/or cytokines
• the camptothecin conjugates may be used in combination with surgery, radiation, chemotherapy, immunotherapy with naked antibodies, radio immunotherapy, immunomodulators, and the like. Similar combinations are preferred in the treatment of the other diseases amenable to targeting moieties, such as cardiovascular, autoimmune, and neurodegenerative diseases.
• the camptothecin conjugates can be combined with TNF inhibitors, B-cell antibodies, and other effective agents for the treatment of autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosis, Sjogren's syndrome, multiple sclerosis, vasculitis, as well as type-I diabetes (juvenile diabetes).
• TNF inhibitors such as rheumatoid arthritis, systemic lupus erythematosis, Sjogren's syndrome, multiple sclerosis, vasculitis, as well as type-I diabetes (juvenile diabetes).
• combination therapies can allow lower doses of each therapeutic to be given in such combinations, thus reducing certain severe side effects, and potentially
• the invention relates to a conjugate comprising: (a) a targeting moiety;
• the invention relates to a conjugate comprising: (a) a targeting moiety;
• the invention relates to a process of preparing conjugates, wherein the linker is first conjugated to a CPT drug, thereby producing a CPT drug-linker conjugate; wherein said CPT drug-linker conjugate preparation involves the selective protection and deprotection of C-IO hydro xyl group, keeping the C-20 carbonate bond essentially intact, in derivatives of CPT containing a C-10 hydro xyl group; wherein said drug-linker conjugate is optionally not purified; and wherein said drug-linker conjugate is subsequently conjugated to a monoclonal antibody or fragment.
• Yet another embodiment of the invention is a method of treating cancer, a malignancy, an autoimmune disease, an infection, or an infectious lesion with the conjugates described herein.
• targeting moiety refers to a molecule, complex or aggregate, that binds specifically or selectively to a target molecule, cell, particle, tissue or aggregate.
• a targeting moiety is an antibody, antibody fragment, bispecific antibody or other antibody-based molecule or compound.
• targeting moieties are known in the art and may be used, such as aptamers, avimers, receptor- binding ligands, nucleic acids, biotin-avidin binding pairs, binding peptides or proteins, etc.
• targeting moiety and “binding moiety” are used synonymously herein.
• An antibody refers to a full-length (i.e., naturally occurring or formed by normal immunoglobulin gene fragment recombinatorial processes) immunoglobulin molecule (e.g., an IgG antibody) or an immunologically active (i.e., specifically binding) portion of an immunoglobulin molecule, like an antibody fragment.
• An antibody or antibody fragment may be conjugated or otherwise derivatized within the scope of the claimed subject matter.
• An antibody fragment is a portion of an antibody such as F(ab') 2 , F(ab) 2 , Fab', Fab, Fv, scFv (single chain Fv) and the like.
• an antibody fragment of use binds with the same antigen that is recognized by the intact antibody.
• antibody fragment also includes any synthetic or genetically engineered protein that acts like an antibody by binding to a specific antigen to form a complex.
• antibody fragments include isolated fragments consisting of the variable regions, such as the "Fv” fragments consisting of the variable regions of the heavy and light chains, recombinant single chain polypeptide molecules in which light and heavy variable regions are connected by a peptide linker ("scFv proteins”), and minimal recognition units consisting of the amino acid residues that mimic the hypervariable region, such as CDRs.
• the Fv fragments may be constructed in different ways to yield multivalent and/or multispecific binding forms.
• antibody component includes both an entire antibody, a fusion protein, and fragments thereof.
• a naked antibody is generally an entire antibody that is not conjugated to a therapeutic agent. This is so because the Fc portion of the antibody molecule provides effector or immunological functions, such as complement fixation and ADCC (antibody dependent cell cytotoxicity), which set mechanisms into action that may result in cell lysis.
• the Fc portion may not be required for therapeutic function of the antibody, but rather other mechanisms, such as apoptosis, anti-angiogenesis, anti-metastatic activity, anti- adhesion activity, such as inhibition of heterotypic or homotypic adhesion, and interference in signaling pathways, may come into play and interfere with the disease progression.
• Naked antibodies include both polyclonal and monoclonal antibodies, and fragments thereof, that include murine antibodies, as well as certain recombinant antibodies, such as chimeric, humanized or human antibodies and fragments thereof. Therefore, in some cases a "naked antibody” may also refer to a "naked” antibody fragment.
• Class III autoimmune diseases such as immune-mediated thrombocytopenias, such as acute idiopathic thrombocytopenic purpura and chronic idiopathic thrombocytopenic purpura, dermatomyositis, Sjogren's syndrome, multiple sclerosis, Sydenham's chorea, myasthenia gravis, systemic lupus erythematosus, lupus nephritis, rheumatic fever, polyglandular syndromes, bullous pemphigoid, diabetes mellitus, Henoch-Schonlein purpura, post-streptococcal nephritis, erythema nodosum, Takayasu's arteritis, Addison's disease, rheumatoid arthritis, sarcoidosis, ulcerative colitis, erythema multiforme, IgA nephropathy, polyarteritis nodosa, an
• a chimeric antibody is a recombinant protein that contains the variable domains of both the heavy and light antibody chains, including the complementarity determining regions (CDRs) of an antibody derived from one species, preferably a rodent antibody, while the constant domains of the antibody molecule are derived from those of a human antibody.
• CDRs complementarity determining regions
• the constant domains of the chimeric antibody may be derived from that of other species, such as a cat or dog.
• a humanized antibody is a recombinant protein in which the CDRs from an antibody from one species; e.g., a rodent antibody, is transferred from the heavy and light variable chains of the rodent antibody into human heavy and light variable domains.
• the constant domains of the antibody molecule are derived from those of a human antibody.
• specific residues of the framework region of the humanized antibody particularly those that are touching or close to the CDR sequences, may be modified, for example replaced with the corresponding residues from the original rodent or other antibody.
• a human antibody is an antibody obtained, for example, from transgenic mice that have been "engineered” to produce specific human antibodies in response to antigenic challenge.
• elements of the human heavy and light chain locus are introduced into strains of mice derived from embryonic stem cell lines that contain targeted disruptions of the endogenous heavy chain and light chain loci.
• the transgenic mice can synthesize human antibodies specific for human antigens, and the mice can be used to produce human antibody-secreting hybridomas. Methods for obtaining human antibodies from transgenic mice are described by Green et al., Nature Genet. 7: 13 (1994), Lonberg et al., Nature 368:856 (1994), and Taylor et al, Int. Immun. 6:579 (1994).
• a fully human antibody also can be constructed by genetic or chromosomal transfection methods, as well as phage display technology, all of which are known in the art.
• antibody variable domain genes are cloned in- frame into either a major or minor coat protein gene of a filamentous bacteriophage, and displayed as functional antibody fragments on the surface of the phage particle. Because the filamentous particle contains a single-stranded DNA copy of the phage genome, selections based on the functional properties of the antibody also result in selection of the gene encoding the antibody exhibiting those properties. In this way, the phage mimics some of the properties of the B cell.
• Phage display can be performed in a variety of formats, for their review, see e.g. Johnson and Chiswell, Current Opinion in Structural Biology 3:5564-571 (1993). Human antibodies may also be generated by in vitro activated B cells. See U.S. Patent Nos. 5,567,610 and 5,229,275, which are incorporated in their entirety by reference. [0030] Infectious Diseases as used herein are diseases involving infection by pathogens such as bacteria, rickettsia, mycoplasma, protozoa, fungi, viruses, parasites, or other microbial agents.
• pathogens such as bacteria, rickettsia, mycoplasma, protozoa, fungi, viruses, parasites, or other microbial agents.
• HIV human immunodeficiency virus
• examples include human immunodeficiency virus (HIV) causing AIDS, Mycobacterium of tuberculosis, Streptococcus agalactiae, methicillin-resistant Staphylococcus aureus, Legionella pneumophilia, Streptococcus pyogenes, Escherichia coli, Neisseria gonorrhosae, Neisseria meningitidis, Pneumococcus, Hemophilis influenzae B,
• a therapeutic agent is a molecule or atom that is administered separately, concurrently or sequentially with a binding moiety, e.g., an antibody or antibody fragment, or a subfragment thereof, and is useful in the treatment of a disease.
• therapeutic agents include, but are not limited to, antibodies, antibody fragments, conjugates, drugs, cytotoxic agents, toxins, nucleases, hormones, immunomodulators, chelators, boron compounds, photoactive agents or dyes, radioisotopes or radionuclides, oligonucleotides, interference RNA, peptides, anti-angio genie agents, chemotherapeutic agents, cyokines, chemikines, drugs, prodrugs, toxins, enzymes, binding proteins or peptides, conjugates or combinations thereo f.
• a conjugate is an antibody component or other targeting moiety conjugated to a therapeutic agent. Suitable therapeutic agents are described above.
• antibody fusion protein is a recombinant ly-produced antigen- binding molecule in which two or more of the same or different natural antibody, single - chain antibody or antibody fragment segments with the same or different specificities are linked.
• a fusion protein comprises at least one specific binding site. Valency of the fusion protein indicates the total number of binding arms or sites the fusion protein has to antigen(s) or epitope(s); i.e., monovalent, bivalent, trivalent or mutlivalent.
• the multivalency of the antibody fusion protein means that it can take advantage of multiple interactions in binding to an antigen, thus increasing the avidity of binding to the antigen, or to different antigens.
• an antibody fusion protein is able to bind; i.e., monospecific, bispecif ⁇ c, trispecific, multispecific.
• a natural antibody e.g., an IgG
• a monospecific, multivalent fusion protein has more than one binding site for the same antigen or epitope.
• a monospecific diabody is a fusion protein with two binding sites reactive with the same antigen.
• the fusion protein may comprise a multivalent or multispecific combination of different antibody components or multiple copies of the same antibody component.
• the fusion protein may additionally comprise a therapeutic agent.
• An immunomo dulator is a therapeutic agent that when present, alters, suppresses or stimulates the body's immune system.
• an immunomodulator of use stimulates immune cells to proliferate or become activated in an immune response cascade, such as macrophages, B-cells, and/or T-cells.
• an immunomodulator of use may suppress proliferation or activation of immune cells, as in therapeutic treatment of autoimmune disease.
• An example of an immunomodulator as described herein is a cytokine, which is a soluble small protein of approximately 5-20 kDs that are released by one cell population (e.g., primed T-lymphocytes) on contact with specific antigens, and which act as intercellular mediators between cells.
• cytokines include lymphokines, monokines, interleukins, and several related signaling molecules, such as tumor necrosis factor (TNF) and interferons.
• TNF tumor necrosis factor
• Chemokines are a subset of cytokines.
• Certain interleukins and interferons are examples of cytokines that stimulate T cell or other immune cell proliferation.
• CPT is abbreviation for camptothecin, and in this application CPT represents camptothecin itself or an analog or derivative of camptothecin.
• Solubility of CPT is enhanced by placing a polyethyleneglycol moiety (PEG) between CPT and the antibody; (2) a lysosomally cleavable linker such as a peptide spacer is placed between CPT and antibody for the intracellular liberation of intact CPT; (3) the lysosomally cleavable peptide spacer is attached through a collapsible linker to CPT in the form of a carbonate, or in the form of a carbamate via an ester at CPT's C-20 position; (4) the antibody- coupling group is designed to be either a thiol or a thiol-reactive group; and (5) methods are devised for selective regeneration of the 10-hydroxyl group in presence of the C-20 carbonate in preparations of drug-linker precursor involving CPT analogs such as SN-38.
• a conjugate comprises an antibody or antibody fragment
• another type of binding moiety such as an aptamer, avimer or targeting
• An exemplary preferred embodiment is directed to a conjugate of a camptothecin drug derivative and an antibody of the general formula 2,
• MAb is a disease-targeting antibody
• CPT is camptothecin (CPT) or an analog thereof
• L is the linker system of the type X-Y-Z wherein X is an antibody- coup ling moiety, Y is a lysosomally cleavable polypeptide, and Z is 4-aminobenzyloxy moiety, which is connected to the CPT drug.
• X and Y may be linked via an amide bond, with an intervening spacer which is a straightchain or cyclic hydrocarbon, or which is a water- so lubilizing moiety such as polyethyleneglycol (PEG).
• AA is an amino acid or polypeptide moiety forming an ester between and the 20-hydroxyl of CPT, and further attached via its (AA's) N-terminus to the 'Z' component of linker 'L'.
• the intracellular ly-cleavable moiety is optionally cleavable by intracellular esterases.
• the intracellularly- cleavable moiety is an ester moiety formed between the carboxylic acid of an amino acid such as glycine, alanine, or sarcosine, or of a peptide such as glycylglycine, and the 20- hydroxyl of CPT.
• the N-terminus of the said amino acid or polypeptide is protected as a Boc or a Fmoc or a monomethoxytrityl (MMT) derivative, which is deprotected after formation of an ester bond with 20-hydroxyl of CPT.
• MMT monomethoxytrityl
• intracellularly-cleavable moiety further comprises a polypeptide as an embodiment of the 'Y' component of linker 'L' that is cleavable by intracellular enzymes such as Cathepsin B.
• the latter product is generated by coupling CPT-derived ester to 'Z' of the linker 'L' shown above, through the activated form of p-aminobenzyl alcohol, namely PABOCOPNP where PNP is /?-nitrophenyl.
• the linker comprises a thiol-reactive group which links to thiol groups of said targeting moiety.
• the thiol-reactive group is optionally a maleimide or vinylsulfone, or bromoacetamide, or iodoacetamide, which links to thiol groups of said targeting moiety.
• said reagent bearing a thiol-reactive group is generated from succinimidyl-4-(N maleimidomethyl)cyclohexane-l- carboxylate (SMCC) or from succinimidyl-( ⁇ -maleimido)caproate, for instance, with the thiol-reactive group being a maleimide group.
• the conjugate contains polyethyleneglycol (PEG) spacer between X and Y of the general formula;
• PEG can be of up to MW 5000 in size, and in a preferred embodiment, PEG is a defined PEG with (1-12 or 1-30) repeating monomeric units, and in a more preferred embodiment, PEG is a defined PEG with 1-12 repeating monomeric units.
• the introduction of PEG may involve using heterobifunctionalized PEG derivatives which are available commercially.
• the heterobifunctional PEG contains an antibody or binding moiety- coupling group such as, for example, a maleimide moiety or a protected thiol moiety as well as an activated ester such as succinimidyl carboxylate.
• an antibody or binding moiety- coupling group such as, for example, a maleimide moiety or a protected thiol moiety as well as an activated ester such as succinimidyl carboxylate.
• An example of a heterobifunctional defined PEG containing 12 repeating monomeric units, with 'NHS' being succinimidyl, is given below in formula 3 : ff C ⁇ f N N (CH 2 ) 2 -CO-NH-(CH 2 ) 2 -(OCH 2 CH 2 )i 2 -COONHS
• the 20-O- AA ester bonding to SN-38 is sarcosinate.
• the 20-O- AA ester bonding to SN-38 is glycinate.
• Method 1 when the 'X' group is a thiol-reactive moiety, the thiols on the antibody are generated on the lysine groups of the antibody using a thiolating reagent.
• Methods for introducing thiol groups on to antibodies by modifications of MAb's lysine groups are well known in the art (Wong in Chemistry of protein conjugation and cross-linking, CRC Press, Inc., Boca Raton, FL (1991), pp 20-22).
• mild reduction of interchain disulfide bonds on the antibody Wang et al, Bioconjugate Chem.
• reducing agents such as dithiothreitol (DTT) can generate 7-to-10 thiols on the antibody; which has the advantage of incorporating multiple CPT moieties upon reaction with [L]-ester-CPT of the general formula given above, in the interchain region of MAb away from antigen-binding region.
• DTT dithiothreitol
• the linker comprises a thiol group that reacts with a thiol-reactive residue introduced at one or more lysine side chain amino groups of said targeting moiety.
• the 'X' group is thiol
• the antibody is pre- derivatized with a thiol-reactive group such as a maleimide, vinylsulfone, bromoacetamide, or iodoacetamide by procedures well described in the art.
• the cleavable peptide Y of Method 1 may be selected from the group consisting of Phe-Lys, Val-Cit (Dubowchik, supra), Ala-Leu, Leu-Ala-Leu, and Ala-Leu- Ala-Leu (Trouet et al., supra).
• the preferred chemotherapeutic moiety is selected from the group consisting of CPT, 10-hydroxy camptothecin, SN-38, topotecan, lurtotecan, 9-aminocamptothecin, 9-nitrocamptothecin, and derivatives thereof.
• the chemotherapeutic moiety is SN-38.
• the targeting moiety links to at least one chemotherapeutic moiety; preferably 1 to about 12 chemotherapeutic moieties; most preferably about 7 to about 12 chemotherapeutic moieties.
• Another exemplary embodiment is directed to a conjugate of a camptothecin drug derivative and an antibody of the general formula 6:
• MAb is a disease-targeting antibody
• CPT is camptothecin (CPT) or an analog thereof
• L is the linker system of the type X-Y-Z wherein X is an antibody- coup ling moiety, Y is a lysosomally cleavable polypeptide, and Z is 4-aminobenzyloxy moiety, which is directly or indirectly connected to the CPT drug; finally, X and Y are linked via an amide bond, with an intervening spacer which is a straight chain or cyclic hydrocarbon, or which is a water- so lubilizing moiety such as polyethyleneglycol (PEG).
• the linker 'L' consisting of X-Y-Z is attached directly or indirectly to 20-0-carbonyl moiety of CPT.
• a representative CPT conjugate of an antibody of Method 2, prepared with a maleimide-containing SN-38-linker derivative, with the bonding to MAb represented as a succinimide, is given below:
• a representative CPT conjugate of an antibody of Method 2, prepared with a maleimide-PEG- containing SN-38-linker derivative, with the bonding to MAb represented as a succinimide, is given below:
• Method 2 Another embodiment of Method 2 is shown by the structural formula 9. All embodiments of the linker 'L' (X-Y-Z), stipulated for Method 1 in paragraphs 0038, 0040, 0041, and 0044-0047 apply to this Method 2 embodiment in their entirety.
• the activated form of 'Z' namely PABOCOPNP where PNP is /?-nitrophenyl, is bonded to a 20- carbamate derivative of CPT, the latter derived from 20-chloro formate of a CPT and a N- monosubstituted, or N,N'-disubstituted, or unsubstituted, ethylenediamine.
• a representative CPT conjugate of an antibody of Method 2, prepared with a maleimide-containing SN-38- linker derivative, with bonding to MAb represented as a succinimide, is given below.
• the N,N'-dimethylethylenediamine is used to link 'L' with 20-chloroformate of SN-38.
• the terminal amino group of the drug-20-carbamate generated after intracellular processing, can cyclize to a 5-membered ring to release free CPT (SN-38 in this case).
• the N,N'-dimethylethylenediamine spacer in the structure below can be substituted with sarcosine hydrazide, with sarcosine amino group reacted with a CPT (or analog such as SN-38)-20-chloro formate, and the hydrazide part coupled to the 'L' linker system.
• the hydrazide liberated after intracellular catabolism of the antibody and the linker can also cyclize to give a 6-membered ring, with the concomitant liberation of free CPT (or analog, such as SN-38) molecule.
• the ethylenediamine version as well as the hydrazide version enumerated herein are within the purview of the present invention.
• the linker comprises a thiol group which reacts with a thiol-reactive residue at a lysine side chain of said targeting moiety, where said thiol-reactive moiety is selected from the group comprising maleimide, vinylsulfone, bromoacetamide, and iodoacetamide.
• a representative CPT conjugate of an antibody of Method 2, prepared with a thiol- containing SN-38-linker derivative, with the bonding to MAb represented as a succinimide, is given below.
• Yet another exemplary embodiment is directed to a conjugate of a camptothecin drug derivative and an antibody of the general formula 11 :
• a representative CPT conjugate of an antibody of Method 3, prepared with a maleimide-PEG- containing SN-38-linker derivative, with the bonding to MAb represented as a succinimide, is given below.
• Other embodiments are additionally directed to a process for producing said MAb- CPT conjugates whereby the linker 'L' of Methods 1-3 is first conjugated to a derivatized form of a CPT drug, and this process is followed by removing protecting groups on some functional groups on the linker as well as that which may be present on CPT, wherby a CPT drug-linker conjugate is obtained.
• the CPT drug-linker conjugate is subsequently conjugated to a MAb or fragment.
• CPT drug-linkers can be prepared wherein CPT additionally has a 10-hydroxyl group.
• This process involves, but is not limited to, the protection of the said 10-hydroxyl group as a t-butyloxycarbonyl (BOC) derivative, followed by the preparation of the penultimate intermediate of the drug-linker conjugate.
• BOC t-butyloxycarbonyl
• removal of BOC group requires treatment with strong acid such as trifluoroacetic acid (TFA).
• TFA trifluoroacetic acid
• the CPT 20-0-linker carbonate, containing protecting groups to be removed is also susceptible to cleavage, thereby giving rise to unmodified CPT.
• the targeting moiety is a monoclonal antibody (MAb).
• the targeting moiety may be a multivalent and/or multispecific MAb.
• the targeting moiety may be a murine, chimeric, humanized, or human monoclonal antibody, and said antibody is in intact, fragment (Fab, Fab', F(ab) 2 , F(ab') 2 ), or sub-fragment (single- chain constructs) form.
• the targeting moiety is a monoclonal antibody that is reactive with an antigen or epitope of an antigen expressed on a cancer or malignant cell.
• the cancer cell is preferably a cell from a hematopoietic tumor, carcinoma, sarcoma, melanoma or a glial tumor.
• a preferred malignancy to be treated according to the present invention is a malignant solid tumor or hematopoietic neoplasm.
• the intracellularly-cleavable moiety may be cleaved after it is internalized into the cell upon binding by the MAb-drug conjugate to a receptor thereof, and particularly cleaved by esterases and peptidases.
• the targeting moiety is preferably an antibody (including fully human, non-human, humanized, or chimeric antibodies) or an antibody fragment (including enzymatically or recombinant Iy produced fragments) and binding proteins incorporating sequences from antibodies or antibody fragments.
• the antibodies, fragments, and binding proteins may be multivalent and multispecific or multivalent and monospecific as defined above.
• antibodies such as MAbs
• MAbs are used that recognize or bind to markers or tumor- associated antigens that are expressed at high levels on target cells and that are expressed predominantly or only on diseased cells versus normal tissues, and antibodies that internalize rapidly.
• Antibodies useful within the scope of the present invention include MAbs with properties as described above (and show distinguishing properties of different levels of internalization into cells and microorganisms), and contemplate the use of, but are not limited to, in cancer, the following MAbs: LLl (anti- CD74), LL2 and RFB4 (anti-CD22), RS7 (anti-epithelial glycoprotein- 1 (EGP-I)), PAM-4 and KC4 (both anti-MUCl), MN- 14 (anti-carcinoembryonic antigen (CEA, also known as CD66e), Mu-9 (anti-co Ion-specific antigen-p), Immu 31 (an anti-alpha- fetoprotein), TAG-72 (e.g., CC49), Tn, J591 (anti-PSMA (prostate-specific membrane antigen)), G250 (an anti- carbonic anhydrase IX MAb) and L243 (anti-HLA-DR).
• MAbs include MAbs with properties
• VEGF alpha-fetoprotein
• ED-B e.g., L19
• EGF receptor or ErbBl e.g., Erbitux ®
• ErbB2 ErbB3, placental growth factor (PlGF)
• MUCl MUC2, MUC3, MUC4, PSMA, gangliosides, HCG, EGP-2 (e.g., 17-1A), CD37, HLA-DR, CD30, Ia, A3, A33, Ep- CAM, KS-I, Le(y), SlOO, PSA (prostate-specific antigen), tenascin, folate receptor, Thomas- Friedenreich antigen
• CD66a-d or a combination thereof.
• the CD66 antigens consist of five different glycoproteins with similar structures, CD66a-e, encoded by the carcinoembryonic antigen (CEA) gene family members, BCG, CGM6, NCA, CGMl and CEA, respectively. These CD66 antigens are expressed mainly in granulocytes, normal epithelial cells of the digestive tract and tumor cells of various tissues. A number of the aforementioned antigens are disclosed in U.S. Provisional Application Serial No. 60/426,379, entitled "Use of Multi- specific, Non-covalent Complexes for Targeted Delivery of Therapeutics," filed November 15, 2002, incorporated herein by reference.
• antibodies are used that internalize rapidly and are then re-expressed, processed and presented on cell surfaces, enabling continual uptake and accretion of circulating conjugate by the cell.
• An example of a most-preferred antibody/antigen pair is LLl, an anti-CD74 MAb (invariant chain, class II- specific chaperone, Ii).
• the CD74 antigen is highly expressed on B-cell lymphomas, certain T-cell lymphomas, melanomas and certain other cancers (Ong et al, Immunology PS:296-302 (1999)), as well as certain autoimmune diseases.
• the diseases that are preferably treated with anti-CD74 antibodies include, but are not limited to, non-Hodgkin's lymphoma, Hodgkin's disease, melanoma, lung cancer, myeloid leukemias, and multiple myeloma.
• Continual expression of the CD74 antigen for short periods of time on the surface of target cells, followed by internalization of the antigen, and re-expression of the antigen enables the targeting LLl antibody to be internalized along with any chemotherapeutic moiety it carries. This allows a high, and therapeutic, concentration of LL 1-chemo therapeutic drug conjugate to be accumulated inside such cells. Internalized LLl- chemotherapeutic drug conjugates are cycled through lysosomes and endosomes, and the chemotherapeutic moiety is released in an active form within the target cells.
• the invention in another aspect, relates to a method of treating a subject, comprising administering a therapeutically effective amount of a therapeutic conjugate of the preferred embodiments of the present invention to a subject.
• Diseases that may be treated with the therapeutic conjugates of the preferred embodiments of the present invention include, but are not limited to B-cell malignancies (e.g., non-Hodgkin's lymphoma and chronic lymphocytic leukemia using, for example LL2 MAb; see U.S. Patent No.
• adenocarcinomas of endodermally-derived digestive system epithelia cancers such as breast cancer and non-small cell lung cancer, and other carcinomas, sarcomas, glial tumors, myeloid leukemias, etc.
• antibodies against an antigen e.g., an oncofetal antigen, produced by or associated with a malignant solid tumor or hematopoietic neoplasm, e.g., a gastrointestinal, lung, breast, prostate, ovarian, testicular, brain or lymphatic tumor, a sarcoma or a melanoma, are advantageously used.
• Such therapeutics can be given once or repeatedly, depending on the disease state and tolerability of the conjugate, and can also be used optimally in combination with other therapeutic modalities, such as surgery, external radiation, radioimmunotherapy, immunotherapy, chemotherapy, antisense therapy, interference RNA therapy, gene therapy, and the like. Each combination will be adapted to the tumor type, stage, patient condition and prior therapy, and other factors considered by the managing physician.
• the term "subject” refers to any animal (i.e., vertebrates and invertebrates) including, but not limited to mammals, including humans.
• the term subject also includes rodents (e.g., mice, rats, and guinea pigs). It is not intended that the term be limited to a particular age or sex. Thus, adult and newborn subjects, as well as fetuses, whether male or female, are encompassed by the term.
• the therapeutic conjugates comprising the Mu-9 MAb of the preferred embodiments of the present invention can be used to treat colorectal, as well as pancreatic and ovarian cancers as disclosed in U.S. Application Serial No.
• the therapeutic conjugates comprising the PAM-4 MAb of the preferred embodiments of the present invention can be used to treat pancreatic cancer, as disclosed in U.S. Provisional Application Serial No. 60/388,314, filed June 14, 2002.
• the therapeutic conjugates comprising the RS-7 MAb of the preferred embodiments can be used to treat carcinomas such as carcinomas of the lung, stomach, urinary bladder, breast, ovary, uterus, and prostate, as disclosed in U.S. Provisional Application Serial No. 60/360,229, filed March 1, 2002 and by Stein et al. ⁇ Cancer Res. 50: 1330 (1990) and Antibody Immunoconj. Radiopharm. 4: 703 (1991)).
• the therapeutic conjugates comprising the anti-AFP MAb of the preferred embodiments can be used to treat hepatocellular carcinoma, germ cell tumors, and other AFP -producing tumors using humanized, chimeric and human antibody forms, as disclosed in U.S. Provisional Application Serial No. 60/399,707, filed August 1, 2002.
• the therapeutic conjugates comprising anti-tenascin antibodies can be used to treat hematopoietic and solid tumors and conjugates comprising antibodies to Le(y) can be used to treat solid tumors.
• the antibodies that are used in the treatment of human disease are human or humanized (CDR-grafted) versions of antibodies; although murine and chimeric versions of antibodies can be used.
• Same species IgG molecules as delivery agents are mostly preferred to minimize immune responses. This is particularly important when considering repeat treatments.
• a human or humanized IgG antibody is less likely to generate an anti-IgG immune response from patients.
• Antibodies such as hLLl and hLL2 rapidly internalize after binding to internalizing antigen on target cells, which means that the chemotherapeutic drug being carried is rapidly internalized into cells as well.
• antibodies that have slower rates of internalization can also be used to effect selective therapy with this invention.
• the therapeutic conjugates of the preferred embodiments can be used against pathogens, since antibodies against pathogens are known.
• antibodies and antibody fragments which specifically bind markers produced by or associated with infectious lesions, including viral, bacterial, fungal and parasitic infections, for example caused by pathogens such as bacteria, rickettsia, mycoplasma, protozoa, fungi, and viruses, and antigens and products associated with such microorganisms have been disclosed, inter alia, in Hansen et al, U.S. Pat. No. 3,927,193 and Goldenberg U.S. Pat. Nos.
• the pathogens are selected from the group consisting of HIV virus causing AIDS, Mycobacterium tuberculosis, Streptococcus agalactiae, methicillin-resistant Staphylococcus aureus, Legionella pneumophilia, Streptococcus pyogenes, Escherichia coli, Neisseria gonorrhosae, Neisseria meningitidis, Pneumococcus, Hemophilis influenzae B, Treponema pallidum, Lyme disease spirochetes, Pseudomonas aeruginosa, Mycobacterium leprae, Brucella abortus, rabies virus, influenza virus, cytomegalovirus, herpes simplex virus
• drug conjugates of present invention comprising anti-gpl20 and other such anti-HIV antibodies can be used as therapeutics for HIV in AIDS patients; and drug conjugates of antibodies to Mycobacterium tuberculosis are suitable as therapeutics for drug-refractive tuberculosis.
• Fusion proteins of anti-gpl20 MAb (anti HIV MAb) and a toxin, such as Pseudomonas exotoxin have been examined for antiviral properties (Van Oigen et al, J Drug Target, 5:75-91, 1998)). Attempts at treating HIV infection in AIDS patients failed possibly due to insufficient efficacy or unacceptable host toxicity.
• the drug conjugates of present invention advantageously lack such toxic side effects of protein toxins, and are therefore advantageously used in treating HIV infection in AIDS patients. These drug conjugates can be given alone or in combination with other antibiotics or therapeutic agents that are effective in such patients when given alone.
• diseases that may be treated using the therapeutic conjugates of the preferred embodiments of the present invention include, but are not limited to immune dysregulation disease and related autoimmune diseases, including Class III autoimmune diseases such as immune-mediated thrombocytopenias, such as acute idiopathic thrombocytopenic purpura and chronic idiopathic thrombocytopenic purpura, dermatomyositis, Sjogren's syndrome, multiple sclerosis, Sydenham's chorea, myasthenia gravis, systemic lupus erythematosus, lupus nephritis, rheumatic fever, polyglandular syndromes, bullous pemphigoid, diabetes mellitus, Henoch-Schonlein purpura, poststreptococcal nephritis, erythema nodosum, Takayasu's arteritis, Addison's disease, rheumatoid arthritis,
• Class III autoimmune diseases such
• Typical antibodies useful in these diseases include, but are not limited to, those reactive with HLA-DR antigens, B-cell antigens (e.g., CD19, CD20, CD21, CD22, CD23, CD4, CD5, CD8, CD14, CD15, CD19, CD20, CD21, CD22, CD23, CD25, CD33, CD37, CD38, CD40, CD40L, CD46, CD52, CD54, CD74, CD80, CD126, B7, MUCl, Ia, HM1.24, and HLA-DR).
• B-cell antigens e.g., CD19, CD20, CD21, CD22, CD23, CD4, CD5, CD8, CD14, CD15, CD19, CD20, CD21, CD22, CD23, CD25, CD33, CD37, CD38, CD40, CD40L, CD46, CD52, CD54, CD74, CD80, CD126, B7, MUCl, Ia, HM1.24, and HLA-DR).
• autoimmune diseases are affected by autoantibodies made by aberrant B-cell populations
• depletion of these B-cells by therapeutic conjugates involving such antibodies bound with the drugs used in this invention is a preferred method of autoimmune disease therapy, especially when B- cell antibodies are combined, in certain circumstances, with HLA-DR antibodies and/or T- cell antibodies (including those which target IL-2 as an antigen, such as anti-TAC antibody).
• the anti-B-cell, anti-T-cell, or anti-macrophage or other such antibodies of use in the treatment of patients with autoimmune diseases also can be conjugated to result in more effective therapeutics to control the host responses involved in said autoimmune diseases, and can be given alone or in combination with other therapeutic agents, such as TNF inhibitors or TNF antibodies, unconjugated B- or T-cell antibodies, and the like.
• diseases that may be treated using the therapeutic conjugates of the current invention include cardiovascular diseases, such as fibrin clots, atherosclerosis, myocardial ischemia and infarction.
• cardiovascular diseases such as fibrin clots, atherosclerosis, myocardial ischemia and infarction.
• Antibodies to fibrin are known and in clinical trials as imaging agents for disclosing said clots and pulmonary emboli, while anti- granulocyte antibodies, such as MN-3, MN- 15, NCA95, and CD 15 antibodies, can target myocardial infarcts and myocardial ischemia, while anti-macrophage, anti- low-density lipoprotein (LDL), and anti-CD74 (e.g., hLLl) antibodies can be used to target atherosclerotic plaques.
• LDL low-density lipoprotein
• anti-CD74 e.g., hLLl
• diseases that may be treated using the therapeutic conjugates of the current invention include neurodegenerative diseases characterized by a specific lesions against which a targeting moiety can be used, such as amyloid or beta-amyloid associated with Alzheimer's disease, and which serves as a target for localizing antibodies.
• a more effective incorporation into cells and pathogens can be accomplished by using multivalent, multispecific or multivalent, monospecific antibodies.
• Multivalent means the use of several binding arms against the same or different antigen or epitope expressed on the cells, whereas multispecific antibodies involve the use of multiple binding arms to target at least two different antigens or epitopes contained on the targeted cell or pathogen. Examples of such bivalent and bispecific antibodies are found in U.S. patent applications 60/399,707, filed August 1, 2002; 60/360,229, filed March 1, 2002; 60/388,314, filed June 14, 2002; and 10/116,116, filed April 5, 2002, all of which are incorporated by reference herein.
• multivalent or multispecific antibodies are particularly preferred in the targeting of cancers and infectious organisms (pathogens), which express multiple antigen targets and even multiple epitopes of the same antigen target, but which often evade antibody targeting and sufficient binding for immunotherapy because of insufficient expression or availability of a single antigen target on the cell or pathogen.
• pathogens infectious organisms
• said antibodies show a higher binding and residence time on the target, thus affording a higher saturation with the drug being targeted in this invention.
• a therapeutic agent used in combination with the camptothecin conjugate of this invention may comprise one or more isotopes, such as 212 Bi, 18 F, 52 Fe, 62 Cu, 64 Cu, 67 Cu, 67 Ga, 68 Ga, 86 Y, 89 Zr, 94 Tc, 94m Tc, 99m Tc, or 111 In.
• Non-radioactive metals such as manganese, iron and gadolinium
• Macrocyclic chelates such as NOTA, DOTA, and TETA are of use with a variety of metals and radiometals, most particularly with radionuclides of gallium, yttrium and copper, respectively. Such metal-chelate complexes can be made very stable by tailoring the ring size to the metal of interest.
• Therapeutic agents for use in combination with the camptothecin conjugate of this invention also include, for example, chemotherapeutic drugs such as vinca alkaloids, anthracyclines, epidophyllotoxins, taxanes, antimetabolites, alkylating agents, antibiotics, Cox-2 inhibitors, antimitotics, antiangio genie and proapoptotic agents, particularly doxorubicin, methotrexate, taxol, other camptothecins, and others from these and other classes of anticancer agents, and the like.
• chemotherapeutic drugs such as vinca alkaloids, anthracyclines, epidophyllotoxins, taxanes, antimetabolites, alkylating agents, antibiotics, Cox-2 inhibitors, antimitotics, antiangio genie and proapoptotic agents, particularly doxorubicin, methotrexate, taxol, other camptothecins, and others from these and other classes of anticancer agents, and the like.
• cancer chemotherapeutic drugs include nitrogen mustards, alkyl sulfonates, nitrosoureas, triazenes, folic acid analogs, pyrimidine analogs, purine analogs, platinum coordination complexes, hormones, and the like.
• Suitable chemotherapeutic agents are described in REMINGTON'S PHARMACEUTICAL SCIENCES, 19th Ed. (Mack Publishing Co. 1995), and in GOODMAN AND GILMAN'S THE PHARMACOLOGICAL BASIS OF THERAPEUTICS, 7th Ed. (MacMillan Publishing Co. 1985), as well as revised editions of these publications.
• Other suitable chemotherapeutic agents, such as experimental drugs are known to those of skill in the art.
• Another class of therapeutic agents consists of radionuclides that emit ⁇ -particles (such as 212 Pb, 212 Bi, 213 Bi, 211 At, 223 Ra, 225 Ac), ⁇ -particles (such as 32 P, 33 P, 47 Sc, 67 Cu, 67 Ga,
• therapeutic agents may comprise a radioisotope useful for diagnostic imaging. Suitable radioisotopes may include those in the energy range of 60 to 4,000 KeV, or more specifically,
• positron emitters such as 18 F, 68 Ga, 94m Tc, and the like, for imaging purposes; incorporated entirely by reference. Detection can be achieved, for example, by single photon emission computed tomography (SPECT), or positron emission tomography (PET).
• SPECT single photon emission computed tomography
• PET positron emission tomography
• Imaging therapeutic agents may include one or more image enhancing agents, which may include complexes of metals selected from the group consisting of chromium (III), manganese (II), iron (III), iron (II), cobalt (II), nickel (II), copper (II), neodymium (III), samarium (III), ytterbium (III), gadolinium (III), vanadium (II), terbium (III), dysprosium (III), holmium (III) and erbium (III).
• image enhancing agents which may include complexes of metals selected from the group consisting of chromium (III), manganese (II), iron (III), iron (II), cobalt (II), nickel (II), copper (II), neodymium (III), samarium (III), ytterbium (III), gadolinium (III), vanadium (II), terbium (III), dysprosium (III),
• a therapeutic agent may comprise one or more radioactive isotopes useful for killing neoplastic or other rapidly dividing cells, which include ⁇ -emitters
• Auger electron emitters such as 111 In, 125 I, 67 Ga, 191 Os, 193m Pt, 195m Pt, 195m Hg
• ⁇ -emitters such as 212 Pb, 212 Bi, 213 Bi, 211 At, 223 Ra, 225 Ac), or a combination thereof.
• Therapeutic agents to be used in concert with the camptothecin conjugates also may be toxins conjugated to targeting moieties.
• Toxins that may be used in this regard include ricin, abrin, ribonuclease (RNase), DNase I, Staphylococcal enterotoxin-A, pokeweed antiviral protein, gelonin, diphtherin toxin, Pseudomonas exotoxin, and Pseudomonas endotoxin.
• RNase ribonuclease
• DNase I DNase I
• Staphylococcal enterotoxin-A Staphylococcal enterotoxin-A
• pokeweed antiviral protein pokeweed antiviral protein
• gelonin gelonin
• diphtherin toxin diphtherin toxin
• Pseudomonas exotoxin Pseudomonas endotoxin.
• Additional toxins suitable for use herein
• a conjugate as disclosed herein may be part of a composite, multispecific antibody.
• Such antibodies may contain two or more different antigen binding sites, with differing specificities.
• the multispecific composite may bind to different epitopes of the same antigen, or alternatively may bind to two different antigens.
• Some of the more preferred target combinations include the following. This is a list of examples of preferred combinations, but is not intended to be exhaustive.
• CD20 + CD22 antibodies CD74 + CD20 antibodies
• CEACAM5 CEA
• CEACAM6 insulin-like growth factor
• ILGF insulin-like growth factor
• EGP-I e.g., RS-7 + ILGF antibodies
• CEACAM5 + EGFR antibodies Such antibodies need not only be used in combination, but can be combined as fusion proteins of various forms, such as IgG, Fab, scFv, and the like, as described in U.S. Patent Nos. 6,083,477; 6,183,744 and 6,962,702 and U.S. Patent Application Publication Nos.
• the binding moieties described herein may comprise one or more avimer sequences.
• Avimers are a class of binding proteins somewhat similar to antibodies in their affinities and specificities for various target molecules. They were developed from human extracellular receptor domains by in vitro exon shuffling and phage display. (Silverman et al, 2005, Nat. Biotechnol. 23:1493-94; Silverman et al, 2006, Nat. Biotechnol. 24:220.)
• the resulting multidomain proteins may comprise multiple independent binding domains, which may exhibit improved affinity (in some cases sub-nanomolar) and specificity compared with single-epitope binding proteins.
• avimers may be attached to, for example, AD and/or DDD sequences for use in the claimed methods and compositions, as described in provisional U.S. Patent Application Serial Nos. 60/668,603, filed 4/6/05 and 60/751196, filed 12/16/05, each incorporated herein in their entirety by reference. Additional details concerning methods of construction and use of avimers are disclosed, for example, in U.S. Patent Application Publication Nos. 20040175756, 20050048512, 20050053973, 20050089932 and 20050221384, the Examples section of each of which is incorporated herein by reference.
• antibody fragments may be obtained by pepsin or papain digestion of whole antibodies by conventional methods.
• antibody fragments may be produced by enzymatic cleavage of antibodies with pepsin to provide a 5 S fragment denoted F(ab')2. This fragment may be further cleaved using a thiol reducing agent and, optionally, a blocking group for the sulfhydryl groups resulting from cleavage of disulfide linkages, to produce 3.5 S Fab' monovalent fragments.
• an enzymatic cleavage using pepsin produces two monovalent Fab fragments and an Fc fragment.
• Exemplary methods for producing antibody fragments are disclosed in U.S. Pat. No. 4,036,945; U.S. Pat. No. 4,331,647; Nisonoff et al, 1960, Arch. Biochem. Biophys., 89:230; Porter, 1959, Biochem. J., 73: 119; Edelman et al., 1967, METHODS IN ENZYMOLOGY, page 422 (Academic
• Fv fragments comprise an association of V H and V L chains. This association can be noncovalent, as described in Inbar et al., 1972, Proc. Nat'l. Acad. Sci. USA, 69:2659.
• the variable chains may be linked by an intermolecular disulfide bond or cross-linked by chemicals such as glutaraldehyde. See Sandhu, 1992, Crit. Rev. Biotech., 12:437.
• the Fv fragments comprise V H and V L chains connected by a peptide linker.
• These single-chain antigen binding proteins are prepared by constructing a structural gene comprising DNA sequences encoding the V H and V L domains, connected by an oligonucleotides linker sequence. The structural gene is inserted into an expression vector that is subsequently introduced into a host cell, such as E. coli. The recombinant host cells synthesize a single polypeptide chain with a linker peptide bridging the two V domains. Methods for producing sFvs are well-known in the art.
• CDR peptides (“minimal recognition units") can be obtained by constructing genes encoding the CDR of an antibody of interest. Such genes are prepared, for example, by using the polymerase chain reaction to synthesize the variable region from RNA of antibody-producing cells. See Larrick et al., 1991, Methods: A
• a chimeric antibody is a recombinant protein in which the variable regions of a human antibody have been replaced by the variable regions of, for example, a mouse antibody, including the complementarity-determining regions (CDRs) of the mouse antibody.
• Chimeric antibodies exhibit decreased immunogenicity and increased stability when administered to a subject.
• Methods for constructing chimeric antibodies are well known in the art ⁇ e.g., Leung et al., 1994, Hybridoma 13:469).
• a chimeric monoclonal antibody may be humanized by transferring the mouse CDRs from the heavy and light variable chains of the mouse immunoglobulin into the corresponding variable domains of a human antibody.
• the mouse framework regions (FR) in the chimeric monoclonal antibody are also replaced with human FR sequences.
• one or more human FR residues may be replaced by the mouse counterpart residues.
• Humanized monoclonal antibodies may be used for therapeutic treatment of subjects.
• the affinity of humanized antibodies for a target may also be increased by selected modification of the CDR sequences (WO0029584A1). Techniques for production of humanized monoclonal antibodies are well known in the art.
• an antibody may be a human monoclonal antibody.
• Such antibodies are obtained from transgenic mice that have been engineered to produce specific human antibodies in response to antigenic challenge.
• elements of the human heavy and light chain locus are introduced into strains of mice derived from embryonic stem cell lines that contain targeted disruptions of the endogenous heavy chain and light chain loci.
• the transgenic mice can synthesize human antibodies specific for human antigens, and the mice can be used to produce human antibody-secreting hybridomas. Methods for obtaining human antibodies from transgenic mice are described by Green et al., Nature Genet. 7:13 (1994), Lonberg et al., Nature 368:856 (1994), and Taylor et al., Int. Immun. 6:579 (1994).
• the claimed methods and procedures may utilize human antibodies produced by such techniques.
• the phage display technique may be used to generate human antibodies (e.g., Dantas-Barbosa et al, 2005, Genet. MoI. Res. 4:126-40, incorporated herein by reference).
• Human antibodies may be generated from normal humans or from humans that exhibit a particular disease state, such as cancer (Dantas-Barbosa et al., 2005).
• the advantage to constructing human antibodies from a diseased individual is that the circulating antibody repertoire may be biased towards antibodies against disease-associated antigens.
• Fab fragment antigen binding protein
• RNAs were converted to cDNAs and used to make Fab cDNA libraries using specific primers against the heavy and light chain immunoglobulin sequences (Marks et al., 1991, J. MoI. Biol. 222:581-97, incorporated herein by reference).
• Library construction was performed according to Andris- Widhopf et al. (2000, In: Phage Display Laboratory Manual, Barbas et al. (eds), 1 st edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY pp. 9.1 to 9.22, incorporated herein by reference).
• Fab fragments were digested with restriction endonucleases and inserted into the bacteriophage genome to make the phage display library.
• libraries may be screened by standard phage display methods. The skilled artisan will realize that this technique is exemplary only and any known method for making and screening human antibodies or antibody fragments by phage display may be utilized.
• transgenic animals that have been genetically engineered to produce human antibodies may be used to generate antibodies against essentially any immunogenic target, using standard immunization protocols as discussed above.
• a non- limiting example of such a system is the XenoMouse® (e.g., Green et al., 1999, J. Immunol. Methods 231 : 11-23, incorporated herein by reference) from Abgenix (Fremont, CA).
• the mouse antibody genes have been inactivated and replaced by functional human antibody genes, while the remainder of the mouse immune system remains intact.
• the XenoMouse® was transformed with germline-conf ⁇ gured YACs (yeast artificial chromosomes) that contained portions of the human IgH and Ig kappa loci, including the majority of the variable region sequences, along accessory genes and regulatory sequences.
• the human variable region repertoire may be used to generate antibody producing B cells, which may be processed into hybridomas by known techniques.
• a XenoMouse® immunized with a target antigen will produce human antibodies by the normal immune response, which may be harvested and/or produced by standard techniques discussed above.
• a variety of strains of XenoMouse® are available, each of which is capable of producing a different class of antibody.
• Such human antibodies may be coupled to other molecules by chemical cross- linking or other known methodologies.
• Transgenically produced human antibodies have been shown to have therapeutic potential, while retaining the pharmacokinetic properties of normal human antibodies (Green et al, 1999).
• the skilled artisan will realize that the claimed compositions and methods are not limited to use of the XenoMouse® system but may utilize any transgenic animal that has been genetically engineered to produce human antibodies.
• the precursors, monomers and/or complexes described herein may comprise one or more avimer sequences.
• Avimers are a class of binding proteins somewhat similar to antibodies in their affinities and specifities for various target molecules. They were developed from human extracellular receptor domains by in vitro exon shuffling and phage display. (Silverman et al., 2005, Nat. Biotechnol. 23:1493-94; Silverman et al., 2006, Nat. Biotechnol. 24:220.)
• the resulting multidomain proteins may comprise multiple independent binding domains, that may exhibit improved affinity (in some cases sub- nanomolar) and specificity compared with single-epitope binding proteins.
• avimers may be attached to, for example, DDD sequences for use in the claimed methods and compositions. Additional details concerning methods of construction and use of avimers are disclosed, for example, in U.S. Patent Application Publication Nos. 20040175756, 20050048512, 20050053973, 20050089932 and 20050221384, the Examples section of each of which is incorporated herein by reference.
• compositions and/or methods may concern binding peptides and/or peptide mimetics of various target molecules, cells or tissues.
• Binding peptides may be identified by any method known in the art, including but not limiting to the phage display technique.
• Various methods of phage display and techniques for producing diverse populations of peptides are well known in the art. For example, U.S. Pat. Nos. 5,223,409; 5,622,699 and 6,068,829, each of which is incorporated herein by reference, disclose methods for preparing a phage library.
• the phage display technique involves genetically manipulating bacteriophage so that small peptides can be expressed on their surface (Smith and Scott, 1985, Science 228:1315-1317; Smith and Scott, 1993, Meth. Enzymo 1. 21 :228-257).
• Targeting amino acid sequences selective for a given organ, tissue, cell type or target molecule may be isolated by panning (Pasqualini and Ruoslahti, 1996, Nature 380:364-366; Pasqualini, 1999, The Quart. J. Nucl. Med. 43:159-162).
• a library of phage containing putative targeting peptides is administered to an intact organism or to isolated organs, tissues, cell types or target molecules and samples containing bound phage are collected.
• Phage that bind to a target may be eluted from a target organ, tissue, cell type or target molecule and then amplified by growing them in host bacteria.
• the phage may be propagated in host bacteria between rounds of panning. Rather than being lysed by the phage, the bacteria may instead secrete multiple copies of phage that display a particular insert. If desired, the amplified phage may be exposed to the target organs, tissues, cell types or target molecule again and collected for additional rounds of panning. Multiple rounds of panning may be performed until a population of selective or specific binders is obtained. The amino acid sequence of the peptides may be determined by sequencing the DNA corresponding to the targeting peptide insert in the phage genome.
• a subtraction protocol may be used to further reduce background phage binding.
• the purpose of subtraction is to remove phage from the library that bind to targets other than the target of interest.
• the phage library may be prescreened against a control cell, tissue or organ.
• tumor- binding peptides may be identified after prescreening a library against a control normal cell line.
• the library may be screened against the molecule, cell, tissue or organ of interest.
• Other methods of subtraction protocols are known and may be used in the practice of the claimed methods, for example as disclosed in U.S Patent Nos. 5,840,841, 5,705,610, 5,670,312 and 5,492,807, incorporated herein by reference.
• a targeting moiety of use may be an aptamer.
• Methods of constructing and determining the binding characteristics of aptamers are well known in the art. For example, such techniques are described in U.S. Patent Nos. 5,582,981, 5,595,877 and 5,637,459, each incorporated herein by reference. Methods for preparation and screening of aptamers that bind to particular targets of interest are well known, for example U.S. Pat. No. 5,475,096 and U.S. Pat. No. 5,270,163, each incorporated by reference.
• Aptamers may be prepared by any known method, including synthetic, recombinant, and purification methods, and may be used alone or in combination with other ligands specific for the same target. In general, a minimum of approximately 3 nucleotides, preferably at least 5 nucleotides, are necessary to effect specific binding. Aptamers of sequences shorter than 10 bases may be feasible, although aptamers of 10, 20, 30 or 40 nucleotides may be preferred.
• Aptamers need to contain the sequence that confers binding specificity, but may be extended with flanking regions and otherwise derivatized.
• the binding sequences of aptamers may be flanked by primer-binding sequences, facilitating the amplification of the aptamers by PCR or other amplification techniques.
• Aptamers may be isolated, sequenced, and/or amplified or synthesized as conventional DNA or RNA molecules.
• aptamers of interest may comprise modified oligomers. Any of the hydro xyl groups ordinarily present in aptamers may be replaced by phosphonate groups, phosphate groups, protected by a standard protecting group, or activated to prepare additional linkages to other nucleotides, or may be conjugated to solid supports.
• One or more phosphodiester linkages may be replaced by alternative linking groups, such as P(O)O replaced by P(O)S, P(O)NR 2 , P(O)R, P(O)OR, CO, or CNR 2 , wherein R is H or alkyl (1-20C) and R' is alkyl (1-20C); in addition, this group may be attached to adjacent nucleotides through O or S. Not all linkages in an oligomer need to be identical.
• the preferred conjugation protocol is based on a thiol-maleimide, a thiol- vinylsulfone, a thiol-bromoacetamide, or a thiol-iodoacetamide reaction that are facile at neutral or acidic pH. This obviates the need for higher pH conditions for conjugations as, for instance, would be necessitated when using active esters.
• Suitable routes of administration of the conjugates of the preferred embodiments of the present invention include, without limitation, oral, parenteral, rectal, transmucosal, intestinal administration, intramuscular, subcutaneous, intramedullary, intrathecal, direct intraventricular, intravenous, intravitreal, intraperitoneal, intranasal, or intraocular injections.
• the preferred routes of administration are parenteral.
• Example 1 Preparation of MC-Phe-Lys-PABOCO-20-O-CPT-lO-O-BOC; and the examination of selective removal of BOC protecting group
• SN-38 (0.5114 g; 1.305 mmol) was reacted with di-tert-butyl dicarbonate (0.307 g) in anhydrous pyridine (8 mL) for 18 h at ambient temperature. The solvent was evaporated, and the crude material was purified by flash chromatography, on silica gel (230-400 mesh) using methanol-dichloro methane gradient, to obtain 0.55 g of pale yellow solid product of l ⁇ -t- butyloxylcarbonyl derivative of SN-38, BOC-SN-38.
• Maleimido-PEGi2 moiety was substituted for maleimidocaproyl of Example 2 using commercially available heterobifunctional cross-linker, maleimide-PEGi 2 -NHS ester (see 0040, formula 3), by reacting the intermediate Phe-Lys(MMT)-PABOH in DMF and diisopropylethylamine, to generate the cross-linker maleimide-PEGi 2 -Phe-Lys(MMT)- PABOH.
• PEG12 is a defined PEG substrate containing 12 monomeric units, and was used to increase the solubility of drug- linker intermediate under MAb conjugation conditions.
• BOC-SN-38 of Example 2 was esterified at the 20-hydroxyl position using BOC-glycine, MMT-glycine, BOC- sarcosine, or BOC-alanine.
• the general procedure involved reacting BOC-SN-38 with ⁇ 20 % molar excess each of amine-protected amino acid (AA) and dicyclohexylcarbodiimide in anhydrous dichloromethane, in presence of catalytic amount of 4-dimethylaminopyridine, in a overnight reaction at ambient temperature.
• the esterified product purified by flash chromatography, was treated with dichloro acetic acid (DCA) to remove just the MMT group, or with TFA to remove the protecting group on both the amine terminus of the ester and the BOC group on SN-38.
• DCA dichloro acetic acid
• TFA to remove the protecting group on both the amine terminus of the ester and the BOC group on SN-38.
• the SN-38 derivative containing C-20 ester, with amine terminus present as TFA or DCA salt, and with 10-hydroxyl protected or free was then reacted with 10% molar excess of MC-Phe-Lys(MMT)-P ABOCOO-PNP (for description, see General section under EXAMPLES) and DIEA in DMF. Purification by flash chromatography furnished the penultimate intermediate in each case, which was reacted with TFA to obtain the title materials.
• Succinimidyl S-methoxytritylthiopropionate was prepared in 2 steps from thiopropionic acid by reacting the latter with a molar equivalent of MMT chloride in anhydrous dichloromethane containing 2.5 equivalents of diisopropylethyamine (DIEA), with MMT being abbreviation for monomethoxytrityl. After the reaction was complete, as monitored by thin-layer chromatography, the reaction mixture was diluted with ethyl acetate, and washed with water and saturated sodium chloride.
• DIEA diisopropylethyamine
• the product purified by flash chromatography, was converted to its succinimidyl ester with equimolar amounts of N- hydroxysuccinimide and dicyclohexylcarbodiimide in DMF.
• the precipitated DCC-urea was filtered off, and the filtrate was used as such for reaction with the intermediate Phe- Lys(MMT)-PABOH (see General section under 'EXAMPLES') in DMF using equimolar amounts of the reactants as well as DIEA.
• the required product was isolated by flash chromatography.
• the product, MMT-S-(CH 2 ) 2 -CO-Phe-Lys(MMT)-PABOH was obtained in 84.7% yield.
• the anti-CD22 humanized MAb, hLL2, the anti-CD74 humanized MAb, hLLl, the anti-EGP-1 humanized MAb, hRS7, and anti-IGFRl chimeric MAb, cRl were used in these studies.
• Each antibody was reduced with dithiothreitol (DTT), used in a 50-to-70-fold molar excess, in 40 mM PBS, pH 7.4, containing 5.4 mM EDTA, at 37 0 C (bath) for 45 min.
• DTT dithiothreitol
• the reduced product was purified on centrifuged size-exclusion column and buffer-exchanged with 75 mM sodium acetae-1 mM EDTA.
• the thiol content was determined by Ellman's assay, and was in the 6.5-to-8.5 SH/IgG range.
• the reduced MAb was reacted with 12.5-to- 22.5-fold molar excess of 'CL-SN-38' of Example 2, or 'PEG-CL-SN-38' of Example 3, or 'CL-AA-SN-38' of Example 4, using DMF at 5-10 % v/v as co-solvent, and incubating for 20 min at ambient temperature.
• the conjugate was purified by centrifuged SEC, passage through a hydrophobic column, and finally by ultrafiltration-diafiltration.
• the product was assayed for SN-38 by absorbance at 366 nm and correlating with standard values, while the protein concentration was deduced from absorbance at 280 nm, corrected for spillover of SN- 38 absorbance at this wavelength. This way, the SN-38/MAb substitution ratios were determined.
• the purified conjugates were stored as lyophilized formulations in glass vials, capped under vacuum and stored in a -20 0 C freezer.
• MSR SN-38 molar substitution ratios
• Example 7 Conjugation of CLS-SN-38 to maleimide-appended antibodies: attachment to lysine side chain of MAbs
• the anti-CD22 humanized MAb, hLL2 and the anti-EGP-1 humanized MAb, hRS7 were examined in these studies. Each antibody was derivatized with7-to- 10-fold molar excess of sulfo-SMCC in PBS, pH 7.4, at 4 0 C for 40 min.
• the conjugate in each case was purified by centrifuged SEC and buffer exchanged with 75 mM sodium acetate- 1 mM EDTA, pH 6.5, diluted to 5 mg/mL, and the pH was adjusted to pH 5 with acetic acid.
• the maleimide-added antibody was then reacted with a slight molar excess ( ⁇ 1.15 equivalent with respect to each maleimide group on the antibody) of 'CLS-SN-38' of Example 5, with DMF used as co- solvent at ⁇ 10 % v/v.
• the conjugates were purified and the SN-38 molar substitutions were determined as described for conjugates of Example 6.
• SN-38 substitution obtained for some of these conjugates, in which the drug is attached to lysine amino groups of MAbs are shown in Table 2 (entries italicized); drug substitutions are typically lower in these than in conjugates of Example 6.
• Example 8 In vitro cytotoxicity of antibody-SN-38 conjugates in lymphoma
• Raji B-lymphoma cells were obtained from American Type Culture Collection (ATCC, Rockville, MD).
• the SN-38 conjugates were prepared from disulfide-reduced anti- CD74 MAb, hLLl, or the negative control MAb anti-EGP-1 MAb, hRS7, used as control, and had the following compositions: hLLl(or hRS7)-[succinimidocaproyl (abbreviated as SC)]-CL-SN-38 and hLLl (or hRS7)-[succinimido-PEGi 2 (abbreviated as S-PEGi 2 )J-CL-SN- 38, where CL is Phe-Lys-P ABOCO moiety, with PAB derived from p-aminobenzyl.
• the lyophilized conjugates were reconstituted with saline to 5 mg/mL.
• Other controls included unmodified hLLl and SN-38 (DMSO solution).
• Cells were harvested and plated into 96 well plates (25,000 cells/well). 20 ⁇ L of serially diluted solutions of conjugates or controls were added to each well to final concentration of 0-7 ⁇ M final concentration of SN-38 equivalent, and incubated at 37 0 C. The media was discarded either at 4 h or 48 h time-point, with washings followed by addition of fresh media. Total incubation time was 48 h.
• MTS dye reduction assay was used to determine dose response curves, and effective EC50 concentrations were determined using PrismPad® Software (Advanced Graphics Software, Encinitas, CA). Table 3 below shows the specific cytotoxicity due to hLLl conjugates.
• hLLl and hRS7 conjugates of bifunctional SN-38 derived from SN-38-20-glycinate or SN-38-20-sarcosinate were evaluated in vitro using Raji cells as described above.
• Specific substrates used were: hLLl-[SC-Phe-Lys-PABOCO-Gly-SN-38] and hLLl-fSC-Phe-Lys-PABOCO-Sar-SN-S ⁇ ], and the non-specific substrates were hRS7- [SC-Phe-Lys-PABOCO-Gly-SN-38] and hRS7-[SC-Phe-Lys-PABOCO-Sar-SN-38].
• Table 4 shows specific cytotoxicity due to these hLLl conjugates. [0125] Table 4: EC50 Values (in drug equivalents) calculated for MAb-SN-38 conjugates against Raji Burkitt's lymphoma, at 4-hr and 48-hr exposure
• the conjugates evaluated were derived from anti-CD74 MAb, hLLl, and had the structures of: hLLl-[succinimidocaproyl (abbreviated as SC)]-CL-SN-38 and hLLl- [succinimido-PEGi2 (abbreviated as S-PEGi 2 )]-CL-SN-38, where CL is Phe-Lys-P ABOCO moiety, with PAB derived from p-aminobenzyl, and Phe and Lys being amino acids phenylalanine and lysine, respectively. 8-Week old female SCID mice were inoculated with 2.5 x 10 6 Raji cells i.v.
• hLLl-[SC-CL]- SN-38 (“hLLl-CL-SN-38") was significantly better than the antibody-alone control (P ⁇ 0.0064).
• Example-10 In vivo therapy of Daudi systemic lymphoma in Severe Combined Immunodeficient (SCID) mice targeted with anti-CD22 hLL2-SN-38 drug conjugate
• mice 8-Week old female SCID mice were inoculated with 1.5 x 10 7 Daudi cells i.v. On the following day, 100, 200, or 500 ⁇ g of hLL2-SN-38 was injected, and this regimen was followed twice weekly for 3 weeks and once in the 4 th week. The controls consisted untreated mice as well as those receiving the equivalent doses of unmodified hLL2. Eight animals per group were used. The animals were monitored daily for signs of disease progression which is hind- limb paralysis and/or > 20% body weight loss.
• Example-11 Elimination of HIV infection by treatment with a SN-38 conjugate of an anti-gpl20 MAb
• An anti-gpl20-SN-38 conjugate with a substitution of ⁇ 8 drug molecules per antibody is obtained.
• An in vitro HIV-inhibition assay with said conjugate is performed by using various mixtures of uninfected Jurkat-T cells and fully HIV-infected Jurkat T-cells (in the ratios of 99.8:2 to 95:5), and treating with serial dilutions of the conjugate, non-specific hRS7-CL- SN38 conjugate control, naked antibody, and HIV-negative serum from 100 to 0.00001 ⁇ g/mL.
• the cells so treated are incubated in RPMI 1640 culture medium at 37 0 C for seven days, and then assayed for HIV inhibition by the relevant ELISA test. This experiment shows a strong and specific inhibition of intercellular spread of HIV by the specific drug conjugate.
• mice with isologous HIV-infected cells together with specific and non-specific SN-38 conjugates are administered to mice with isologous HIV-infected cells together with specific and non-specific SN-38 conjugates.
• primary murine splenocytes infected by HIV- 1/MuLV pseudotype virus are intraperitoneally transferred to groups of mice simultaneously with immunoconjugate administration. Peritoneal cells are harvested 10 days later. While infectious HIV presence is demonstrated in control mice, no infectious HIV is detected in mice treated with 100 ⁇ g or less of anti-gpl20-SN-38 conjugate. No protection is seen with mice treated with control conjugates.

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