Daratumumab drug conjugates and their preparation

Abstract

The present invention provides antibody-linker-drug conjugates, wherein the antibody is daratumumab and the drug is an auristatin analog or a pharmaceutically acceptable salt thereof. The present invention also provides processes for preparing the antibody-linker conjugates of the present invention.

Description

[Technical Field]

[0001] The present invention provides antibody-linker-drug conjugates, wherein the antibody is daratumumab and the drug is an auristatin analog. [Background technology]

[0002] Antibody-drug conjugates (ADCs), consisting of an antibody, a linker, and a cytotoxic agent (drug), are one of the most complex drug platforms in the oncology therapeutic armamentarium. [1] They are payload delivery systems, and the major variables that influence their success include (i) the rate of internalization of the payload; (ii) the expression of the target antigen on tumor and normal tissues, which has implications for both patient selection and therapeutic index; (iii) the linker chemistry and the extracellular as well as intracellular stability inherent in the choice of chemistry; and (iv) the choice of payload for tumor indication. [2] The mechanism of action of ADC involves direct binding between an antibody and its targeted cell surface antigen, and intracellular or extracellular release of the cytotoxic drug. [3] In 2015, the CD38 antibody daratumumab was approved by the U.S. Food and Drug Administration (FDA) for the treatment of multiple myeloma. [4, 5] CD38 is a 46 kDa type II transmembrane glycoprotein with a short 20 aa N-terminal cytoplasmic tail and a long 256 aa extracellular domain. [6] The functions ascribed to CD38 encompass receptor-mediated adhesion and signaling events, as well as an important bifunctional ectoenzyme activity that contributes to intracellular calcium mobilization. [7]Daratumumab binds to CD38, which is overexpressed on the surface of multiple myeloma cells, resulting in tumor cell death through complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and other mechanisms directly related to functional changes in the surface antigen after binding. The present invention provides daratumumab-derived antibody-drug conjugates that enable the specific delivery of drugs (auristatin and / or its analogs) to cancer cells overexpressing CD38. Summary of the Invention

[0003] The present invention provides antibody-linker-drug conjugates, wherein the antibody is daratumumab and the drug is an auristatin analog. The present invention also provides a process for preparing the antibody-linker conjugates of the present invention. The present invention is also directed to the antibody-linker-drug conjugates in the treatment of cancer, autoimmune diseases, or infectious diseases.

[0004] Abbreviation: Ab: Antibody ADC: Antibody drug conjugate HP-SEC: High-performance size-exclusion chromatography IRS: Internal Reference Standard MMAE: Monomethylauristatin E MMAF: Monomethyl auristatin F PAB: paraaminobenzyl PABC: para-aminobenzyl carbamate SDS PAGE: sodium dodecyl sulfate polyacrylamide gel electrophoresis TCEP: Tris(2-carboxyethyl)phosphine

[0005] Aspects of the invention Aspect 1: In one aspect, the present invention provides a compound of formula I: [ka] wherein the antibody (Ab) is daratumumab; -Aa-Ww-Yy- is an enzymatically cleavable linker unit linking the drug unit to the antibody, where -A- is a stretcher unit; a is 1; each -W- is independently an amino acid unit; -Y- is a spacer unit; w is an integer ranging from 2 to 12, y is 1 or 2; p is ranging from 1 to about 20; and the drug (D) is selected from MMAE and MMAF, which are defined by the following structures: [ka]

[0006] In a further aspect, the present invention provides a compound of formula [ka] wherein the antibody (Ab) is daratumumab; -Aa-Ww-Yy- is an enzymatically cleavable linker unit linking the drug unit to the antibody, where: -A- is a stretcher unit; a is 1; each -W- is independently an amino acid unit selected from -phenylalanine-lysine- or -valine-citrulline-; -Y- is a spacer unit selected from -glycine-glycine- or p-aminobenzyl alcohol (PAB) or p-aminobenzylcarbamate (PABC); w is an integer ranging from 2 to 12, y is 1 or 2; p is in the range of 1 to about 20; and the drug (D) is selected from MMAE and MMAF, which are defined by the following structures: [ka]

[0007] where A is defined by the following structure: [ka] r is an integer ranging from 1 to 10; where the carbonyl end of -A- forms a bond with the amino acid unit (W) and the succinimide end of -A- forms a bond with the antibody (Ab).

[0008] In a preferred embodiment, the present invention provides an antibody drug conjugate (ADC) structure represented by: wherein the mAb is a monoclonal antibody comprising light chain variable region complementarity determining region (CDR) sequences CDR1 (RASQSVSSYLA, SEQ ID NO: 1), CDR2 (DASNRAT, SEQ ID NO: 2), and CDR3 (QQRSNWPPTF, SEQ ID NO: 3) and heavy chain variable region CDR sequences CDR1 (SFAMS, SEQ ID NO: 4), CDR2 (AISGSGGGTYYADSVKG, SEQ ID NO: 5), and CDR3 (DKILWFGEPVFDY, SEQ ID NO: 6). In this embodiment, the antibody is daratumumab.

[0009] Further aspects: In a second aspect, the present invention provides a pharmaceutical composition comprising an antibody drug conjugate, preferably a daratumumab drug conjugate as embodied in aspect 1, and an acceptable carrier. An acceptable carrier is known in the art and is defined as any suitable pharmaceutical excipient that is compatible with the active pharmaceutical ingredient (API) of the present invention, i.e., the antibody drug conjugate herein.

[0010] In a third aspect, the present invention provides a process for preparing an antibody drug conjugate, preferably a daratumumab drug conjugate, as performed in aspect 1, wherein the process comprises a) purification of the antibody daratumumab; b) partial reduction of daratumumab; and c) conjugation of the partially reduced daratumumab with a vc-MMAE drug linker.

[0011] In a further embodiment, the daratumumab drug conjugates according to the present invention may be used in the treatment of cancer.

[0012] In still a further embodiment, the daratumumab drug conjugates according to the present invention may be used in the treatment of autoimmune or infectious diseases.

[0013] In a further embodiment, the daratumumab drug conjugate according to the present invention may be used alone as monotherapy in the treatment of cancer.

[0014] In still a further embodiment, the daratumumab drug conjugate according to the present invention may be used alone as monotherapy in the treatment of autoimmune or infectious diseases.

[0015] In a further embodiment, the daratumumab drug conjugates according to the present invention may be used in combination with other drug products in the treatment of cancer, autoimmune diseases, or infectious diseases.

[0016] In further embodiments, the conjugates of the present invention may be administered either intravenously (iv), intramuscularly (im), subcutaneously (sc), intraperitoneally (ip), or any other suitable route of administration.

[0017] In a further embodiment, the dose of the antibody drug conjugate (ADC) according to the invention may range from 0.1 mg / kg to 10 mg / kg.

[0018] In a further aspect, the present invention provides a route of administration of the daratumumab drug conjugate in a subject via intravenous (iv), intramuscular (im), subcutaneous (sc), intraperitoneal (ip), or any other suitable route of administration. [Brief explanation of the drawings]

[0019] [Figure 1] Figure 1 demonstrates the drug-antibody ratio (DAR) of daratumumab-MMAE conjugates analyzed by HP-HIC. [Figure 2] FIG. 2 demonstrates the polypeptide profile of the daratumumab-MMAE conjugate of the invention by SDS-PAGE analysis. [Figure 3] Figure 3 demonstrates the in vitro cytotoxicity assay of daratumumab-MMAE conjugates using Daudi cells. [Figure 4] Figure 4 demonstrates the efficacy of daratumumab ADC in a Burkitt's lymphoma xenograft disease model in SCID mice. DETAILED DESCRIPTION OF THE INVENTION

[0020] Definition: The term "linker" refers to any chemical moiety capable of covalently linking a compound, usually a drug, such as an auristatin, to a cell-binding agent, such as daratumumab. The linker includes a stretcher unit (-A-), an amino acid unit (-W-), and a spacer unit (-Y-), as defined by the following formula:

[0021] [ka]

[0022] Under conditions in which the compound or antibody remains active, the linker may be sensitive or substantially resistant to acid-induced cleavage, photo-induced cleavage, peptidase-induced cleavage, esterase-induced cleavage, and disulfide bond cleavage. Suitable linkers are well known in the art and include, for example, disulfide groups, thioether groups, acid-labile groups, photolabile groups, peptidase-labile groups, and esterase-labile groups. Linkers also include charged linkers and hydrophilic forms thereof, as described herein and known in the art.

[0023] The term "pharmaceutical composition" refers to a preparation that is in a form that clearly allows the biological activity of the active ingredient to be effective and does not contain additional components that are significantly toxic to the subject to which the formulation will be administered. The terms "pharmaceutical formulation," "formulation," "pharmaceutical composition," or "composition" may be used interchangeably herein.

[0024] The terms "patient" and "subject" are used interchangeably and are used in their conventional sense to refer to the living body that suffers from or is prone to the condition that can be prevented or treated by administering the compositions of the present invention, and include animals.The term "animal" refers to human or non-human animals, including but not limited to agricultural animals such as cows, sheep, pigs, goats and horses; domestic mammals such as dogs and cats; laboratory animals including rodents such as mice, rats and guinea pigs; birds including domestic, wild and game birds, such as chickens, turkeys and other galliformes, ducks, geese, and non-human primates including but not limited to monkeys, chimpanzees and other apes and monkey species.The terms do not imply a specific age.Therefore, adult, juvenile and newborn individuals are included.

[0025] In the context of cancer, the term "treating" includes any or all of the following: preventing the growth of tumor or cancer cells, preventing the replication of tumor or cancer cells, reducing the overall tumor burden, and ameliorating one or more symptoms associated with the disease.

[0026] In the context of autoimmune disease, the term "treating" includes any or all of the following: preventing the replication of cells associated with the autoimmune disease state, including but not limited to cells capable of producing autoimmune antibodies, reducing the amount of autoimmune antibodies, and ameliorating one or more symptoms of the autoimmune disease.

[0027] In the context of infectious diseases, the term "treating" includes any or all of the following: preventing the growth, proliferation, or replication of the pathogen that causes the infectious disease and / or host cells infected with the pathogen, as well as ameliorating one or more symptoms of the infectious disease.

[0028] The phrase " pharmaceutically acceptable salt " used herein refers to the pharmaceutically acceptable organic or inorganic salt of the drug (payload) of the present invention.Preferred salts include but are not limited to sulfate, citrate, acetate, oxalate, chloride, bromide, iodide, nitrate, bisulfate, phosphate, acid phosphate, isonicotinate, lactate, salicylate, acid citrate, tartrate, oleate, tannate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisate, fumarate, gluconate, glucaronate, saccharinate, formate, benzoate, glutamate, methanesulfonate, ethanesulfonate, benzenesulfonate. Unless otherwise specified, a or an means "one or more."

[0029] An antibody-drug conjugate (ADC) is defined as an antibody component or a fragment thereof conjugated with a therapeutic agent. As used herein, the terms "antibody-drug conjugate," "antibody-linker-drug," "conjugate," and "immunoconjugate" are used interchangeably herein. A preferred antibody-drug conjugate of the present invention is a daratumumab-MMAE conjugate. "Daratumumab-MMAE conjugate" and "daratumumab vedotin" are used interchangeably.

[0030] Detailed Description of the Invention The present invention provides [ka] wherein the antibody (Ab) is daratumumab; -Aa-Ww-Yy- is an enzymatically cleavable linker unit linking the Drug unit to the antibody, where: -A- is a Stretcher unit; a is 1; each -W- is independently an amino acid unit; -Y- is a Spacer unit; w is an integer ranging from 2 to 12; y is 1 or 2; p is in the range of 1 to about 20; and the Drug (D) is an auristatin analog or a pharmaceutically acceptable salt thereof.

[0031] Antibody (Ab): The antibody of the antibody drug conjugate (ADC) of the present invention is a CD-38 targeting antibody, preferably daratumumab, or any post-translational modification of the antibody or its antibody variant. Post-translational modifications of the antibody include, but are not limited to, deamidation, acidic, basic, or oxidative variants of the antibody, or any other variants that do not significantly affect the biological function or efficacy of the antibody. In one embodiment, the antibody of the antibody drug conjugate (ADC) of the present invention is a daratumumab variant. The daratumumab variant of the present invention includes amino acid substitutions, insertions, and / or deletions in the polypeptide sequence of the antibody daratumumab.

[0032] In one embodiment, the antibody of the antibody-drug conjugate (ADC) of the present invention is a daratumumab variant. The daratumumab variant of the present invention includes amino acid substitutions, insertions, and / or deletions in the polypeptide sequence of the antibody daratumumab. In another embodiment, the CD-38-targeting antibody of the present invention is an antibody comprising the light chain variable region complementarity-determining region (CDR) sequences CDR1 (RASQSVSSYLA, SEQ ID NO: 1), CDR2 (DASNRAT, SEQ ID NO: 2), and CDR3 (QQRSNWPPTF, SEQ ID NO: 3) and the heavy chain variable region CDR sequences CDR1 (SFAMS, SEQ ID NO: 4), CDR2 (AISGSGGGTYYADSVKG, SEQ ID NO: 5), and CDR3 (DKILWFGEPVFDY, SEQ ID NO: 6). The sequences are listed in the International Nonproprietary Names for Medicines (INN, Vol. 24, No. 1, 2010) for the daratumumab product.[8]The antibody of the antibody drug conjugate (ADC) of the present invention is daratumumab, and has a light chain sequence (EIVLTQSPAT LSLSPGERAT LSCRASQSVS SYLAWYQQKP GQAPRLLIYD ASNRATGIPA RFSGSGSGTD FTLTISSLEP EDFAVYYCQQ RSNWPPTFGQ GTKVEIKRTV AAPSVFIFPP SDEQLKSGTA SVVCLLNNFY PREAKVQWKV DNALQSGNSQ ESVTEQDSKD STYSLSSTLT LSKADYEKHK VYACEVTHQG LSSPVTKSFN RGEC, SEQ ID NO: 7) and a heavy chain sequence (EVQLLESGGG LVQPGGSLRL SCAVSGFTFN SFAMSWVRQA PGKGLEWVSA ISGSGGGTYY ADSVKGRFTI SRDNSKNTLY LQMNSLRAED TAVYFCAKDK ILWFGEPVFD YWGQGTLVTV SSASTKGPSV FPLAPSSKST SGGTAALGCL VKDYFPEPVT VSWNSGALTS GVHTFPAVLQ SSGLYSLSSV VTVPSSSLGT QTYICNVNHK PSNTKVDKRV EPKSCDKTHT CPPCPAPELL GGPSVFLFPP KPKDTLMISR TPEVTCVVVD VSHEDPEVKF NWYVDGVEVH NAKTKPREEQ YNSTYRVVSV LTVLHQDWLN GKEYKCKVSN KALPAPIEKT ISKAKGQPRE PQVYTLPPSR EEMTKNQVSL TCLVKGFYPS DIAVEWESNG QPENNYKTTP PVLDSDGSFF LYSKLTVDKS RWQQGNVFSC SVMHEALHNH YTQKSLSLSP GK, SEQ ID NO: 8). Daratumumab is an immunoglobulin G1 kappa (IgG1κ) human monoclonal antibody directed against the CD38 antigen and is produced in a mammalian cell line (Chinese hamster ovary [CHO]) using recombinant DNA technology. Daratumumab has a molecular weight of approximately 148 kDa.In one embodiment, the antibody of the antibody drug conjugate (ADC) of the present invention is daratumumab or a variant thereof, which can improve the binding affinity of the ADC to the CD38 antigen. In one or more embodiments, the antibody of the antibody drug conjugate (ADC) of the present invention is daratumumab or a variant thereof, which can improve the binding affinity of the ADC to the CD38 antigen at a suitable pH. The preferred pH may be pH 6.0 or pH 7.0. In another embodiment, the antibody of the present invention is daratumumab or a variant thereof, which can be used to increase the half-life of the ADC.

[0033] Linker units: The linker unit of the antibody-linker-drug conjugate connects the drug unit and the antibody unit and has the formula:

[0034] [ka]

[0035] where: -A- is the stretcher unit; a is 0 or 1; each -W- is independently an amino acid unit; w is independently an integer ranging from 0 to 12; -Y- is a spacer unit; Y is 0, 1, or 2.

[0036] Stretcher unit: The Stretcher unit (-A-), when present, links the antibody unit to the amino acid unit (-W-). In this regard, the antibody (Ab) has a functional group that can form a bond with a functional group of the Stretcher. Useful functional groups that can be present on the antibody, either naturally or through chemical manipulation, include, but are not limited to, sulfhydryl (-SH), amino, hydroxyl, carboxy, the anomeric hydroxyl group of a carbohydrate, and carboxyl. Preferred antibody functional groups are sulfhydryl and amino.

[0037] The Stretcher unit (-A-) of the present invention is defined by the following structure: [ka] r is an integer ranging from 1 to 10; where the carbonyl end of -A- forms a bond with the amino acid unit (W) and the succinimide end of -A- forms a bond with the antibody (Ab).

[0038] In one embodiment, the Stretcher unit forms a bond with a sulfur atom of the Antibody unit. The sulfur atom can be derived from a sulfhydryl group of the antibody. A representative Stretcher unit of this embodiment is illustrated below: [ka]

[0039] Amino acid unit (-W-): The amino acid unit (-W-), when present, links the Stretcher unit to the Spacer unit if the Spacer unit is present, the Stretcher unit to the Drug unit if the Spacer unit is absent, or the antibody unit to the Drug unit if the Stretcher unit and Spacer unit are absent.

[0040] -Ww- is a dipeptide, tripeptide, tetrapeptide, pentapeptide, hexapeptide, heptapeptide, octapeptide, nonapeptide, decapeptide, undecapeptide, or dodecapeptide unit. The amino acid units of the ADCs of the invention can be enzymatically cleaved by one or more enzymes, including tumor-associated proteases, to liberate the drug unit (-D). An exemplary Ww unit is represented by the formula: [ka]

[0041] where R 20 is isopropyl, and R 21 is (CH2)3NHCONH2.

[0042] Spacer Unit: When an amino acid unit is present, the spacer unit (-Y-), when present, links the amino acid unit to the drug unit. Alternatively, when the amino acid unit is absent, the spacer unit links the stretcher unit to the drug unit. When both the amino acid unit and the stretcher unit are absent, the spacer unit also links the drug unit to the antibody unit. Spacer units are of two general types: self-immolative and non-self-immolative. In one embodiment, the spacer unit (-Y-) of the present invention can be self-immolative or non-self-immolative. A non-self-immolative spacer unit is one in which, after specifically enzymatic cleavage of the amino acid unit from the drug-linker-antibody conjugate, some or all of the spacer unit remains attached to the drug unit. Examples of non-self-immolative spacer units include, but are not limited to, a (glycine-glycine) spacer unit and a glycine spacer unit. When a compound of the invention containing a glycine-glycine spacer unit or a glycine spacer unit undergoes enzymatic cleavage via a tumor cell-associated protease, a cancer cell-associated protease, or a lymphocyte-associated protease, the glycine-glycine-drug moiety or glycine-drug moiety is cleaved from Ab-Aa-Ww-. In one embodiment, -Y y - is a p-aminobenzyl alcohol (PAB) unit. In one embodiment, the present invention provides a drug-linker compound or antibody-linker drug conjugate in which the spacer unit is absent (=0). In one embodiment, -Y- is a p-aminobenzyl alcohol (PAB) group, which is connected to -W through the amino nitrogen atom of the PAB group. w - which is connected directly to -D via a carbonate, carbamate, or ether group.

[0043] Drug Unit: The present invention provides antibody drug conjugates, wherein the antibody is daratumumab and the drug is an auristatin analog selected from MMAE and MMAF, which are defined by the following formula: [ka]

[0044] Antibody-drug conjugates of the present invention The present invention provides antibody-drug conjugates, wherein the antibody is daratumumab or a variant thereof targeting the CD-38 antigen, and the drug or payload is an auristatin analog, preferably MMAE. A preferred antibody-drug conjugate of the present invention is a daratumumab-MMAE conjugate, also referred to as daratumumab vedotin. The daratumumab-MMAE conjugate of the present invention comprises daratumumab or a variant thereof as the antibody, mc-vc-PABC as the linker, and MMAE as the toxin, drug, or payload. The conjugate of the present invention also encompasses a pharmaceutical salt of the payload, i.e., MMAE. The inventors of the present invention have found that the daratumumab-MMAE conjugate of the present invention produces significantly better biological activity in CD-38-expressing cancers in in vivo and in vitro studies in xenograft animal models compared to an approved drug conjugate treatment (Darzalex®). The novel drug conjugates of the present invention are better than the approved drug conjugate Darzalex®.

[0045] It is anticipated that the biological activity of the daratumumab-MMAE of the present invention will extrapolate to clinical use in humans. The novel drug conjugate of the present invention is also superior to the approved drug conjugate, i.e., Darzalex®, in that it is effective at significantly lower drug concentrations than the approved drug conjugate, Darzalex®, and is equally or better effective while making the drug less expensive and potentially less toxic to patients.

[0046] Process for preparing the antibody drug conjugate of the present invention: The antibody of the present invention, preferably daratumumab, was expressed in CHO (Chinese Hamster Ovary) cells using recombinant technology. The cells were cultured in cell culture medium at a suitable pH and temperature for a specific period of time. After completion of cell incubation, the cell culture was harvested, and the antibody was isolated and purified by suitable chromatography techniques. The antibody of the present invention, preferably daratumumab, was reduced with a reducing agent such as tris(2-carboxyethyl)phosphine (TCEP) in phosphate buffer at a pH ranging from 5 to 8.5 and a temperature of about 37°C for 120 minutes. Alternatively, the daratumumab of the present invention can be reduced with dithiothreitol (DTT). The reduced daratumumab was reacted with about a 5-10 molar excess of the linker-drug conjugate of the present invention. The linker-drug conjugate of the present invention is Vedotin, which is commercially available. Vedotin of the present invention comprises a mc-vc-PABC linker conjugated to a monomethyl auristatin (MMAE) payload, also known as vc-MMAE or mc-vc-PABC-MMAE. The conjugate was purified by ultrafiltration-diafiltration. The drug-antibody ratio (DAR) was determined by HPLC-HIC column method. The drug-antibody ratios (DAR) obtained for daratumumab vedotin of the present invention were typically in the range of 1 to 8, preferably 3 to 5, and more preferably 3.5 to 4.5. For long-term storage, purified drug conjugate aliquots were stored under frozen conditions at -25±5°C.

[0047] Uses of the conjugates of the present invention: In another aspect, the antibody drug conjugates of the present invention can be used to treat a subject, comprising administering to the subject a therapeutically effective amount of a therapeutic conjugate described herein, preferably a daratumumab drug conjugate. The effective dose of the conjugate can range from 0.1 mg / kg to 10 mg / kg. Diseases that can be treated with the daratumumab drug conjugate include cancer, autoimmune and / or infectious diseases, multiple myeloma, rheumatoid arthritis, polyarteritis nodosa, essential cryoglobulinemic vasculitis, cutaneous leukocytoclastic vasculitis, Kawasaki disease, Takayasu's arteritis, giant cell arthritis, Henoch-Schönlein purpura, primary or isolated cerebral vasculitis, erythema nodosum, thromboangiitis obliterans, thrombotic thrombocytopenic purpura (including hemolytic uremic syndrome), and cutaneous leukocytoclastic vasculitis. secondary vasculitis, including vasculitis (e.g., secondary to hepatitis B, hepatitis C, Sjögren's syndrome, or systemic lupus erythematosus), erythema nodosum, allergic vasculitis, panniculitis, Weber-Christian disease, hyperglobulinemic purpura, and Buerger's disease; skin diseases, such as contact dermatitis, linear IgA dermatosis, vitiligo, pyoderma gangrenosum, epidermolysis bullosa acquisita, pemphigus vulgaris (including cicatricial pemphigoid and bullous pemphigoid); alopecia areata (including alopecia universalis and totalis); Alopecia areata (including alopecia areata), dermatitis herpetiformis, erythema multiforme, and chronic autoimmune urticaria (including angioneurotic edema and urticarial vasculitis), immune cytopenias such as autoimmune neutropenia and pure red cell aplasia; connective tissue disorders such as CNS lupus, discoid lupus erythematosus, CREST syndrome, mixed connective tissue disease, polymyositis / dermatomyositis, inclusion body myositis, cryoglobulinemia types I and II, fibromyalgia, phospholipid antibody syndrome, secondary hemophilia, relapsing polychondritis , sarcoidosis, stiff-man syndrome, and rheumatic fever, eosinophilic fasciitis, ankylosing spondylitis, juvenile chronic arthritis, adult Still's disease, and SAPHO syndrome, sacroiliitis, reactive arthritis, Still's disease, gout; blood disorders, such as aplastic anemia, primary hemolytic anemia (including cold agglutinin syndrome), or systemic lupus erythematosus; POEMS syndrome, pernicious anemia, and Waldenstrom's hyperglobulinemic purpura, but are not limited to these.Further examples are agranulocytosis, autoimmune neutropenia, Franklin's disease, Seligman's disease, gamma heavy chain disease, and factor VIII inhibitor formation; endocrine disorders, such as polyendocrine disorders, and Addison's disease; further examples are autoimmune hypoglycemia, autoimmune hypothyroidism, insulin autoimmune syndrome, de Quervain's thyroiditis, and insulin resistance mediated by insulin receptor antibodies; hepato-gastrointestinal disorders, such as celiac disease, Whipple's disease, primary biliary cirrhosis, chronic active hepatitis, and primary sclerosing cholangitis; further examples are autoimmune gastritis; nephropathies, such as rapidly progressive glomerulonephritis, poststreptococcal nephritis, Goodpasture's syndrome, membranous glomerulonephritis, and cryoglobulinemic nephritis, minimal change disease; neuropathy, such as autoimmune neuropathy, mononeuritis multiplex, Lambert-Eaton syndrome, Myasthenic syndrome, Sydenham chorea, tabes dorsalis, and Guillain-Barré syndrome, myelopathy / tropical spastic paraparesis, myasthenia gravis, acute inflammatory demyelinating polyneuropathy, and chronic inflammatory demyelinating polyneuropathy; multiple sclerosis; heart and lung disorders, such as COPD, fibrosing alveolitis, bronchiolitis obliterans, allergic aspergillosis, cystic fibrosis, Löffler's syndrome, myocarditis, and pericarditis; Further examples are hypersensitivity pneumonitis and allergic disorders, e.g., bronchial asthma and hyper-IgE syndrome, amaurosis fugax; ophthalmologic disorders, e.g., idiopathic chorioretinitis, infectious diseases, e.g., parvovirus B infection (including stocking-glove syndrome); gynecological and obstetric disorders, e.g., recurrent miscarriage, infertility, and intrauterine growth retardation, paraneoplastic syndromes secondary to gynecological tumors; male reproductive disorders, e.g., paraneoplastic syndromes secondary to testicular tumors;

[0048] Such therapeutic agents may be given once or repeatedly, depending on the state of the disease and the tolerability of the conjugate, and may be used alone as monotherapy or in combination with other treatment modalities, such as surgery, external radiation, immunoradiation, immunotherapy, chemotherapy, antisense therapy, interfering RNA therapy, gene therapy, and the like. Each combination will be tailored to the tumor type, stage, patient condition, and prior treatment history, as well as other factors considered by the managing physician.

[0049] Formulation and Administration Suitable administration routes for the daratumumab drug conjugate of the present invention include, but are not limited to, oral, parenteral, rectal, transmucosal, intestinal administration, intramuscular, subcutaneous, intramedullary, intrathecal, direct intracerebroventricular, intravenous, intravitreal, intraperitoneal, intranasal, or intraocular injection.The preferred administration route is parenteral.Alternatively, the compound can be administered in a local rather than systemic manner, for example, by injecting the compound directly into a solid tumor.

[0050] The antibody-drug conjugate of the present invention, preferably daratumumab drug conjugate, can be formulated according to known methods for preparing pharmaceutically useful compositions.Therefore, the antibody-drug conjugate is mixed with a suitable pharmaceutically excipient.Sterile phosphate buffered saline is one example of suitable pharmaceutically excipient.Other suitable excipients are well known to those skilled in the art.

[0051] In some embodiments, the present invention provides an antibody-linker-drug conjugate (ADC) of formula (I): [ka] wherein the antibody (Ab) is a CD-38 targeting antibody; -Aa-Ww-Yy- is an enzymatically cleavable linker unit connecting the drug unit (D) to the antibody, wherein: -A- is a stretcher unit; a is 1; each -W- is independently an amino acid unit; -Y- is a spacer unit; w is an integer ranging from 2 to 12, and y is 1 or 2; p is ranging from 1 to about 20; drug (D) is a suitable auristatin analog selected from MMAE and MMAF, defined by the following structures: [ka] Here, the wavy line represents the connection point for the linker.

[0052] In another embodiment, the invention provides an antibody-linker-drug conjugate, wherein: -A- is a Stretcher unit; -W- are amino acid units independently selected from -phenylalanine-lysine- or -valine-citrulline-; and -Y- is a spacer unit selected from -glycine-glycine- or p-aminobenzyl alcohol (PAB) or p-aminobenzyl carbamate (PABC).

[0053] In another embodiment, the present invention provides an antibody-linker-drug conjugate, wherein: -A- is a Stretcher unit defined by the following structure: [ka]

[0054] where r is an integer ranging from 1 to 10; and where the carbonyl end of -A- forms a bond with the amino acid unit (W) and the succinimide end of -A- forms a bond with the antibody (Ab).

[0055] In yet another embodiment, the invention provides an antibody-linker-drug conjugate (ADC), wherein the mAb is a monoclonal antibody comprising light chain variable region complementarity-determining region (CDR) sequences CDR1 (RASQSVSSYLA, SEQ ID NO: 1), CDR2 (DASNRAT, SEQ ID NO: 2), and CDR3 (QQRSNWPPTF, SEQ ID NO: 3) and heavy chain variable region CDR sequences CDR1 (SFAMS, SEQ ID NO: 4), CDR2 (AISGSGGGTYYADSVKG, SEQ ID NO: 5), and CDR3 (DKILWFGEPVFDY, SEQ ID NO: 6); the enzymatically cleavable linker unit is mc-vc-PABC, and the drug (D) is a suitable auristatin analog MMAE.

[0056] In yet another aspect, the present invention provides an antibody-linker-drug conjugate (ADC), wherein the ADC structure is represented by: [ka]

[0057] In another aspect, the present invention provides that the mAb is a monoclonal antibody comprising light chain variable region complementarity determining region (CDR) sequences CDR1 (RASQSVSSYLA, SEQ ID NO: 1), CDR2 (DASNRAT, SEQ ID NO: 2), and CDR3 (QQRSNWPPTF, SEQ ID NO: 3) and heavy chain variable region CDR sequences CDR1 (SFAMS, SEQ ID NO: 4), CDR2 (AISGSGGGTYYADSVKG, SEQ ID NO: 5), and CDR3 (DKILWFGEPVFDY, SEQ ID NO: 6).

[0058] In some embodiments, the present invention provides antibody drug conjugates (ADCs) wherein the mAb is a monoclonal antibody comprising the constant domain and hinge domain of a human IgG1 antibody.

[0059] In some embodiments, the present invention provides antibody drug conjugates (ADCs), wherein the mAb is a monoclonal antibody comprising the constant domain and hinge domain of a human IgG1 antibody, and one or more amino acids in the Fc portion are mutated.

[0060] In another embodiment, the present invention provides an antibody drug conjugate (ADC), wherein the mAb is the monoclonal antibody daratumumab or a variant thereof.

[0061] In yet another aspect, the present invention provides antibody drug conjugates (ADCs) wherein the mAb is attached to between 1 and 8, preferably 3-5, more preferably 3.5-4.5, drug moieties.

[0062] In one aspect, the present invention provides a pharmaceutical composition comprising an antibody drug conjugate (ADC) of the invention and an acceptable carrier.

[0063] In certain aspects, the present invention provides a process for preparing an antibody drug conjugate of the invention, wherein the process comprises: a) purification of the antibody daratumumab; b) partial reduction of daratumumab; and c) conjugation of the reduced daratumumab with a vc-MMAE drug linker.

[0064] In another aspect, the present invention provides antibody drug conjugates (ADCs), wherein the conjugates are in a form suitable for parenteral administration, e.g., intravenous (iv), intramuscular (im), subcutaneous (sc), intraperitoneal (ip), or any other suitable route of administration.

[0065] In yet another embodiment, the present invention provides an antibody drug conjugate (ADC), wherein the ADC is used to treat cancer.

[0066] In yet another embodiment, the present invention provides antibody drug conjugates (ADCs), wherein the ADCs are used to treat infections by pathogenic organisms.

[0067] In a further aspect, the present invention provides antibody drug conjugates (ADCs), which are used to treat autoimmune diseases.

[0068] In still further embodiments, the present invention provides antibody drug conjugates (ADCs), wherein the ADCs are administered as monotherapy or in combination with one or more therapeutic agents selected from the group consisting of an unconjugated antibody, a radiolabeled antibody, a drug-conjugated antibody, a toxin-conjugated antibody, gene therapy, chemotherapy, a therapeutic peptide, an oligonucleotide, local radiation therapy, surgery, and an interfering RNA therapy.

[0069] In another embodiment, the present invention provides an antibody drug conjugate (ADC), wherein the dose of the ADC is about 0.1 mg / kg to 10 mg / kg.

[0070] In some embodiments, the present invention provides that the antibody drug conjugate (ADC) is daratumumab vedotin.

[0071] Example 1: Preparation of daratumumab-linker-drug conjugate Daratumumab was expressed in CHO cells and purified by conventional column chromatography, including r-Protein A affinity, strong cation exchange, and mixed-mode column chromatography. The purity of daratumumab, as assessed by HP-SEC, was found to be 99.5%. Conjugation of daratumumab (>1 mg / mL) to thiol (-SH) groups was performed under reducing conditions with a molar excess (relative to the protein) of valine-citrulline-coupled MMAE drug at a pH between 5.0 and 8.5 and a temperature between 2°C and 30°C. The linker-drug conjugate was dissolved in 5–20% acetonitrile before mixing with the protein solution. The linker-drug conjugate could also be dissolved in other organic solvents, such as dimethyl acetate or dimethyl sulfoxide. The conjugation reaction was carried out for approximately 60 minutes. After conjugation, the antibody drug conjugate (daratumumab-MMAE conjugate) was buffer exchanged, filtered through a 0.2μ filter, and stored at or below −20° C. Purity was observed by HP-SEC analysis as listed in Table 1.

[0072] Table 1: Purity of daratumumab drug conjugates by HP-SEC analysis [Table 1] The antibody drug conjugate was observed to exhibit a purity of approximately 95% by HP-SEC analysis.

[0073] Daratumumab-MMAE conjugates can also be prepared by the method described in Example 2.

[0074] Example 2: Method for preparing daratumumab-MMAE conjugate Daratumumab monoclonal antibody was expressed in Chinese hamster ovary (CHO) cells. Purification was performed using conventional column chromatography steps, including r-Protein A affinity column chromatography, cation exchange chromatography, and mixed-mode column chromatography. After purification, the purity of the antibody was determined to be greater than 99% using high-performance size-exclusion chromatography (HP-SEC).

[0075] Conjugation of vcMMAE drugs with daratumumab: The purified daratumumab monoclonal antibody was subjected to chemical conjugation with vc-MMAE. The vc-MMAE matrix is ​​also known as Vedotin, which was purchased from the market. The process steps are described as follows:

[0076] Thawing of critical intermediate (CI, i.e., daratumumab) The CI was stored in frozen form in cryopreservation bags. Thawing was performed manually in the same cryopreservation bags. After thawing, the CI (daratumumab) material was transferred to a suitable container for the next reaction step.

[0077] Partial reduction of CI with TCEP Daratumumab was subjected to partial reduction (interchain S-S crosslinking) in the presence of a molar excess of tris(carboxyethyl)phosphine [TCEP] for approximately 300 min. For the reaction, the incubation temperature was maintained at or below 37°C under stirring (200 rpm). At the end of the reaction, the protein mixture was passed through a 0.2 μm filter and collected in a clean, depyrogenated glass bottle (2 L) for the next reaction step.

[0078] Drug-linker conjugation with CI TCEP-treated daratumumab was incubated with a molar excess of the drug-linker vc-MMAE (valine-citrulline monomethyl auristatin E). The incubation was carried out under cold conditions for 120 min with gentle agitation (200 rpm). Conjugation occurred via the formation of a covalent thioether bond between the free -SH group (interchain) of the partially reduced daratumumab protein and the maleimide group of the drug-linker vc-MMAE. At the end of the conjugation reaction, the reaction mixture was passed through a 0.2 μm filter and subjected to UF / DF for removal of unreacted drug-linker molecules.

[0079] Removal of excess drug-linker by UF / DF and buffer exchange After filtration, the crude reaction mixture containing daratumumab vedotin was subjected to UF / DF to remove unreacted vcMMAE drug-linker, followed by a final buffer exchange. A 30 kDa MWCO membrane filter was used for UF / DF. UF / DF was performed at a maximum transmembrane pressure (TMP) of 0.50 bar. Constant-volume diafiltration was performed using 20 mM Na-citrate buffer at pH 6.6 ± 0.1 and a conductivity of 4.5 ± 0.5 mS / cm for up to 30 diavolumes. The retentate pH and conductivity were monitored and controlled during diafiltration to achieve target values. After achieving the target pH and conductivity, daratumumab vedotin was recovered at approximately 7 mg / mL and passed through a 0.2 μm filter.

[0080] Preparation of formulated bulk The concentrated protein solution was collected in a clean, depyrogenated glass bottle. Trehalose was added to it from a freshly prepared 30% stock solution (0.2 μm filtered) to achieve a final concentration of 7% (w / v). Polysorbate 80 was then added to a final concentration of 0.02%, and the final volume of the bulk was adjusted by adding drug substance buffer to achieve a protein concentration of 5 mg / mL for daratumumab vedotin. In a biosafety cabinet, the formulated bulk of daratumumab vedotin was passed through a 0.2 μm filter and collected in a single-use, sterile, nonpyrogenic polyethylene terephthalate glycol (PETG) bottle with a white, high-density polyethylene (HDPE) screw cap. The filtered formulated bulk was labeled as daratumumab vedotin drug substance.

[0081] Example 3: Drug-to-Antibody Ratio (DAR) of Daratumumab-MMAE Conjugates The daratumumab vedotin drug substance sample from Example 3 was analyzed by analytical hydrophobic interaction chromatography (HIC)-HPLC to evaluate the distribution of drug-linkers (Dl) on daratumumab. Peaks are separated by HIC based on the relative hydrophobicity of drug-conjugated antibodies (ADCs) with 0 to 8 payloads (drug toxins). This technique also allows for the determination of the average drug-to-antibody ratio (DAR) for daratumumab vedotin. The experiment was performed using a butyl (4.6 x 100 mm; 5 μm) column coupled to an HPLC system. The sample containing daratumumab vedotin drug substance was injected onto the HIC column saturated with mobile phase A (50 mM phosphate pH 7.0 and 1.2 M ammonium sulfate buffer containing 5% isopropyl alcohol) at 25°C. Daratumumab vedotin with various payloads was eluted from the column with mobile phase B (50 mM phosphate, pH 7.0, containing 20% ​​isopropyl alcohol) at 1.0 mL / min in decreasing salt concentration mode, and the elution was recorded by UV detection at 214 nm. Figure 1 illustrates the appearance of drug-linked antibody variants obtained from three independent batches of daratumumab vedotin.

[0082] As shown in Figure 1, all three daratumumab vedotin drug substance samples were found to exhibit five prominent peaks, corresponding to DAR0, DAR2, DAR4, DAR6, and DAR8. The retention time (RT) values ​​of the individual peaks obtained by the batch samples were observed to be nearly identical to each other. Daratumumab vedotin obtained from all derived batches exhibited an average DAR of 4±1, preferably a DAR of about 1 to 8, more preferably about 3.5 to 4.5, in HP-HIC analysis, as provided in Table 2 and Figure 1 below.

[0083] Table 2: % Drug-to-Antibody Ratio (DAR) of Daratumumab-MMAE Conjugates [Table 2]

[0084] Example 4: Polypeptide profile of daratumumab-linker-drug conjugate using SDS PAGE electrophoresis.

[0085] Preparation of daratumumab-linker-drug conjugates: Daratumumab-linker-drug conjugates were prepared according to the process described in Example 1.

[0086] SDS PAGE electrophoresis: Apparatus: BIO-RAD electrophoresis system. Electrophoresis buffer composition: 0.0247 M Tris, 0.192 M glycine, 0.1% SDS, pH 8.3±0.1.

[0087] Sample preparation: During sample loading, each sample along with the internal reference standard was diluted with Milli-Q water and 5x sample buffer in such a way that each gel well was loaded with 10 μg protein.

[0088] Polypeptide profile of daratumumab-linker-drug conjugates (daratumumab ADCs): The polypeptide profile of the daratumumab ADC is demonstrated in Figure 2, which depicts the results of SDS-PAGE analysis of various samples obtained during the conjugation reaction of the daratumumab ADC, including purified daratumumab in lanes 4 and 5. SDS-PAGE analysis of the samples was performed under non-reducing conditions. The internal reference standard, brentuximab vedotin, was also analyzed under the same conditions as a positive control. After SDS-PAGE analysis, single bands were observed in lanes 4 and 5, indicating that daratumumab was intact in borate buffer after buffer exchange. Lane 6 of the non-reducing SDS-PAGE shows multiple bands of heterogeneous species of mAb after partial reduction with 2.7 M TCEP. The conjugated samples in lanes 8, 9, and 10 demonstrate successful conjugation, as each payload-bearing band is shifted toward higher molecular weights compared to the TCEP-treated sample in lane 6.

[0089] Example 5: In vitro cytotoxicity study of daratumumab-linker-drug conjugates Daudi (ATCC CCL-213, B lymphoblastoid) cells were seeded in 96-well black clear-bottom plates (Costar 3603). The cell line was chosen because it is known to express the CD38 receptor. The cells were treated with different concentrations of daratumumab-MMAE conjugate and Darzalex and incubated for 2 hours in a CO2 incubator. After incubation, excess or unbound daratumumab-MMAE was removed, and fresh medium was added and incubated at 37°C in 5% CO2 for 4 days. At the end of the incubation, alamar blue dye (Invitrogen, DAL-1100) was added to the cells and incubated for 5 hours in a CO2 incubator. After incubation, viable cells were quantified by measuring the fluorescent signal at an excitation wavelength of 530 nm and an emission wavelength of 590 nm using a SpectraMax M2E fluorescent plate reader. Figure 3 shows that the relative in vitro activity of the tested daratumumab-MMAE conjugates is better than Darzalex. Without effector function, the daratumumab antibody alone does not exhibit activity. However, the daratumumab-MMAE conjugates exhibit good in vitro activity without the requirement for effector cell-mediated killing. Thus, the data demonstrate that the daratumumab-MMAE conjugates of the present invention are active and non-inferior to Darzalex.

[0090] Example 6: Efficacy of daratumumab ADC in a Burkitt's lymphoma xenograft disease model in SCID mice In this study, the therapeutic potential of the novel daratumumab ADC was evaluated in comparison with the daratumumab antibody alone. Specifically, to induce Burkitt's lymphoma xenografts, immunodeficient SCID mice were injected with Daudi cells (1:1 ratio of cell suspension and Matrigel, 1 million cells / animal / 200 μL volume) into the right flank region of the animal. Animals were observed for tumor development and drug administration was initiated when the animals' mean tumor volume reached approximately 20-25 mm3. Here, in this study, daratumumab ADC and daratumumab were compared head-to-head at a dose level of 5 mg / kg (IV route, single administration).

[0091] Figure 4 below demonstrates the efficacy of daratumumab ADC compared to daratumumab in the Daudi Burkitt lymphoma cell line. Here, daratumumab, at a dose of 5 mg / kg, was able to delay tumor progression compared to the placebo control group, but was unable to regress tumor burden. At the same time, daratumumab ADC was able to regress tumor burden at a similar dose. This indicates that daratumumab ADC has good potential to regress Burkitt lymphoma tumors with CD38 overexpression and demonstrated clear superiority over the available anti-CD38 therapeutic daratumumab monoclonal antibody.

[0092] References incorporated into this patent application: 1. Diamantis N, Banerji U. Antibody-drug conjugate-an emerging class of cancer treatment. Br J Cancer 2015; 114:362-367. 2. Bouchard H, Viskov C, Garcia-Echeverria C. Antibody-drug conjugates-a new wave of cancer drugs. Bioorganic Med.Chem Lett 2014; 24:5357-5363. 3. Tolcher AW, Ann Oncol. 2016; 27:2168-2172. 10.1093 / annoc / mdw424. [PubMed:27733376] 4. Lokhorst HM, Plesner T, Laubach JP, Nahi H, Gimsing P, Hansson M, Minnema MC, Lassen U, Krejcik J, Palumbo A, van de Donk NWCJ, Ahmadi T, Khan I, Uhlar CM, Wang J, Sasser AK, Losic N, Lisby, Basse JN, JN, JN and Brunson PG. Med.2015; 373:1207-1219. 10.1056 / NEJMoa1506348. [PubMed:26308596] 5.de Weers M, Tai Y- T, van der Veer MS, Bakker JM, Vink T, Jacobs DCH, Oomen LA, Peipp M, Valerius T, Slootstra JW, Mutis T, Bleeker WK, Anderson KC, Lokhorst HM, van de Winkel JGJ and Parren PWHI, J Immunol. 2011; 186:1840-1848. 10.4049 / jimmunol.1003032. [PubMed:21187443] 6. Malavasi, F., A. Funaro, S. Roggero, A. Horenstein, L. Calosso, and K. Mehta. 1994. Human CD38:a glycoprotein in search of a function. Immunol. Today 15:95-97. 7. Mehta, K., and F. Malavasi, eds. 2000. Human CD38 and Related Molecules. Karger, Basel, Switzerland. 8. WHO Drug Information, Vol.24, No.1, 2010 Recommended INN:List 63 41 International Non-proprietary Names for Pharmaceutical Substances (INN).

[0093] Incorporation by Reference The entire disclosure of each of the patent documents and scientific articles referenced herein is incorporated by reference for all purposes.

[0094] equivalent The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The foregoing embodiments, therefore, are to be considered in all respects as illustrative and not limiting of the invention described herein. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims

1. An antibody-linker-drug conjugate (ADC) of formula (I): 【Chemistry 1】 wherein the antibody (Ab) is a CD-38 targeting antibody; -Aa-Ww-Yy- is an enzymatically cleavable linker unit connecting the drug unit (D) to the antibody, wherein: -A- is a stretcher unit; a is 1; each -W- is independently an amino acid unit; -Y- is a spacer unit; w is an integer ranging from 2 to 12, y is 1 or 2; p ranges from 1 to about 20; drug (D) is a suitable auristatin analog selected from MMAE and MMAF, defined by the following structures: 【Chemistry 2】 wherein the wavy line represents the point of attachment to the linker.

2. 2. The antibody-linker-drug conjugate of claim 1, wherein -A- is a stretcher unit; -W- are amino acid units independently selected from -phenylalanine-lysine- or -valine-citrulline-; and -Y- is a spacer unit selected from -glycine-glycine- or p-aminobenzyl alcohol (PAB) or p-aminobenzylcarbamate (PABC).

3. -A- is a Stretcher unit defined by the following structure: 【Transformation 3】 wherein r is an integer ranging from 1 to 10; and wherein the carbonyl terminus of -A- forms a bond with the amino acid unit (W) and the succinimide terminus of -A- forms a bond with the antibody (Ab).

4. 4. The antibody-linker-drug conjugate (ADC) of claim 3, wherein the mAb is a monoclonal antibody comprising light chain variable region complementarity determining region (CDR) sequences CDR1 (RASQSVSSYLA), CDR2 (DASNRAT), and CDR3 (QQRSNWPPTF) and heavy chain variable region CDR sequences CDR1 (SFAMS), CDR2 (AISGSGGGTYYADSVKG), and CDR3 (DKILWFGEPVFDY); the enzymatically cleavable linker unit is mc-vc-PABC, and the drug (D) is a suitable auristatin analog MMAE.

5. The ADC structure is represented by: 【Chemistry 4】 The antibody-linker-drug conjugate (ADC) of claim 4, wherein the mAb is a monoclonal antibody comprising light chain variable region complementarity-determining region (CDR) sequences CDR1 (RASQSVSSYLA), CDR2 (DASNRAT), and CDR3 (QQRSNWPPTF) and heavy chain variable region CDR sequences CDR1 (SFAMS), CDR2 (AISGSGGGTYYADSVKG), and CDR3 (DKILWFGEPVFDY).

6. 6. The antibody drug conjugate (ADC) of claim 5, wherein the mAb is a monoclonal antibody comprising the constant domain and hinge domain of a human IgG1 antibody.

7. 7. The antibody drug conjugate (ADC) of claim 6, wherein the mAb is a monoclonal antibody comprising the constant domain and hinge domain of a human IgG1 antibody, and one or more amino acids in the Fc portion are mutated.

8. 8. The antibody drug conjugate (ADC) of claim 6 or 7, wherein the mAb is the monoclonal antibody daratumumab or a variant thereof.

9. 9. The antibody drug conjugate (ADC) of any one of claims 1 to 8, wherein the mAb is attached to between 1 and 8, preferably 3 to 5, more preferably 3.5 to 4.5 drug moieties.

10. A pharmaceutical composition comprising the antibody drug conjugate (ADC) of any one of claims 1 to 9 and an acceptable carrier.

11. 11. A process for preparing the antibody drug conjugate of any one of claims 1 to 10, the process comprising: a) purification of the antibody daratumumab; b) partial reduction of daratumumab; and c) conjugation of the reduced daratumumab with a vc-MMAE drug linker.

12. 12. The antibody drug conjugate (ADC) of any one of claims 1 to 11, wherein the conjugate is in a form suitable for parenteral administration, for example intravenously (iv), intramuscularly (im), subcutaneously (sc), intraperitoneally (ip), or any other suitable route of administration.

13. The antibody drug conjugate (ADC) of any one of claims 1 to 12, wherein the ADC is used to treat cancer.

14. The antibody drug conjugate (ADC) of any one of claims 1 to 13, wherein the ADC is used to treat infection by a pathogenic organism.

15. The antibody drug conjugate (ADC) of any one of claims 1 to 14, wherein the ADC is used to treat an autoimmune disease.

16. 16. The antibody drug conjugate (ADC) of any one of claims 1 to 15, wherein the ADC is administered as a monotherapy or in combination with one or more therapeutic agents selected from the group consisting of an unconjugated antibody, a radiolabeled antibody, a drug-conjugated antibody, a toxin-conjugated antibody, gene therapy, chemotherapy, a therapeutic peptide, an oligonucleotide, localized radiation therapy, surgery, and an interfering RNA therapy.

17. 17. The antibody drug conjugate (ADC) of any one of claims 1 to 16, wherein the dose of the ADC is about 0.1 mg / kg to 10 mg / kg.

18. 18. The antibody drug conjugate (ADC) of any one of claims 1 to 17, which is daratumumab vedotin.

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