Medication Regimen

Abstract

The present disclosure relates to dosing regimens for the treatment of proliferative disorders with antibody drug conjugates (ADCs), in particular to therapeutic methods involving administration of ADCs using a flat dosing regimen.

Description

[Technical field]

[0001] The present disclosure relates to novel dosing regimens for the treatment of pathological conditions, such as cancer, using antibody drug conjugates (ADCs). In particular, the disclosure relates to novel dosing regimens, including flat dosing regimens. [Background technology]

[0002] Kidney-associated antigen 1 (KAAG1) is an antigen recognized by cytolytic T lymphocytes. KAAG1 is an attractive novel tumor target for ADC development that is highly expressed on the tumor cell surface in tumors with high unmet medical needs, including ovarian, prostate, and triple-negative breast cancer, but its expression on healthy tissues is highly restricted. KAAG1 internalizes and colocalizes with the lysosomal marker lysosomal-associated membrane protein 1 (LAMP1), indicating efficient target trafficking to this cellular compartment. In 2013, ovarian cancer caused an estimated 239,000 new cases and 152,000 deaths worldwide each year. A woman's lifetime risk of developing ovarian cancer is 1 in 75, and her chance of dying from the disease is 1 in 100. Advanced stages of ovarian cancer are associated with high morbidity and poor survival rates, despite extensive research in the field. The lack of promising screening tools for early detection is one of the major challenges associated with poor survival rates in ovarian cancer patients. The disease usually develops at a late stage with a 5-year relative survival rate of only 29%. A minority of cases (15%) are diagnosed with localized tumors (stage 1), with a 5-year survival rate of 92%. Surprisingly, the 5-year relative overall survival rate is generally in the range of 30%-40% worldwide, with only a slight increase (2%-4%) since 1995. Ovarian cancer is managed therapeutically using a multimodality approach including debulking surgery, chemotherapy, and (rarely) radiation therapy. Recently, there has been growing interest in using immunomodulation for the treatment of ovarian cancer. Recurrence rates are high in this malignant tumor. Further treatments after recurrence are more intensive, resulting in a high economic burden for patients with toxicity, resistance to chemotherapy drugs, and poor quality of life.

[0003] Prostate cancer is one of the most common causes of cancer death in American men. In 2007, approximately 219,000 new cases will be diagnosed, with an expected 27,000 deaths from the disease. Treatment of prostate cancer once it has metastasized (spread from the prostate) is currently extremely limited. Systemic therapy is limited to various forms of androgen (male hormone) deprivation. Although most patients show initial clinical improvement, androgen-independent cells virtually inevitably develop. Thus, endocrine therapy is a palliative, not curative, treatment. Median overall survival in patients who develop androgen-independent cells ranged from 28 to 52 months from the start of hormonal treatment. After the development of androgen independence, only taxane-based (i.e., docetaxel) chemotherapy has been shown to provide a survival benefit, with a median survival of 19 months. If patients no longer respond to docetaxel, median survival is 12 months. When prostate cancer is localized and the patient has a life expectancy of 10 years or more, radical prostatectomy is the best chance for eradicating the disease. Historically, the drawback of this procedure is that many cancers have spread beyond the limits of surgery before they are detected. However, prostate-specific antigen testing has allowed for early detection of prostate cancer. As a result, surgery is less complication-prone and more limited in scope. Patients with bulky, high-grade tumors are less likely to be successfully treated with radical prostatectomy. Radiation therapy is also widely used as an alternative to radical prostatectomy. Patients who are generally treated with radiation therapy are older, less healthy, and have more aggressive, clinically more advanced tumors. However, persistent cancer is indicated when there is detectable serum prostate-specific antigen concentration after surgery or radiation therapy. In many cases, prostate-specific antigen concentration can be reduced by radiation therapy. However, the concentration often increases again within two years.

[0004] Breast cancer is the second leading cause of cancer death and the most common cancer among women worldwide, occurring in 24% of all women (approximately 2.1 million cases in 2018). Triple-negative breast cancer (TNBC), a specific subtype of breast cancer that does not express estrogen receptor (ER), progesterone receptor (PR), or human epidermal growth factor receptor 2 (HER-2), has clinical characteristics that include high invasiveness, high metastatic potential, propensity for recurrence, and poor prognosis. Epidemiological data indicate that TNBC occurs mostly in premenopausal young women under the age of 40, which account for approximately 15-20% of all breast cancer patients. Compared to other subtypes of breast cancer, TNBC patients have a shorter survival time, with a mortality rate of 40% within the first 5 years after diagnosis. TNBC is highly aggressive, with approximately 46% of TNBC patients developing distant metastases. The median survival time after metastasis is only 13.3 months, and the recurrence rate after surgery is high at 25%. Metastases frequently involve the brain and visceral organs. The average time to recurrence in TNBC patients is only 19-40 months, and the mortality rate of TNBC patients within 3 months after recurrence is as high as 75%. TNBC tumors do not express ER, PR, and HER2, are not sensitive to endocrine therapy or HER2 therapy, and there is still no standardized TNBC treatment regimen. Chemotherapy is the main systemic treatment, but the efficacy of conventional adjuvant chemoradiotherapy is low. Residual metastatic lesions eventually lead to tumor recurrence. Summary of the Invention [Problem to be solved by the invention]

[0005] Thus, there is a need for therapies to treat ovarian, prostate and triple-negative breast cancer. [Means for solving the problem]

[0006] Disclosed herein is a method of treating a proliferative disorder in a subject comprising administering an ADC using a flat dosing regimen rather than a weight-based dosing regimen, which has not been used in approved ADC therapies to date. Accordingly, the disclosure provides a method of treating a proliferative disorder in a subject, comprising administering to the subject an antibody-drug conjugate (ADC), wherein the drug is a pyrrolobenzodiazepine (PBD) dimer, and the ADC is administered to the subject using a flat dosing regimen for one or more cycles. In one embodiment, the dose of the ADC administered per cycle is 2 to 20 mg. In one embodiment, the dose of the ADC administered per cycle is 2 to 5 mg, 6 to 10 mg, 11 to 15 mg, or 16 to 20 mg. In one embodiment, the dose of the ADC administered per cycle is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 mg.

[0007] In one embodiment, the antibody specifically binds to a tumor antigen, hi one embodiment, the tumor antigen is CD19, CD22, CD25, AXL, DLK-1, or KAAG1. In one embodiment, the PBD dimer has the following formula I:

[0008] [ka] (In the formula, (a)R LL is a linker for linking to an Ab; (b)(i)R 10 and R 11 (ii) R 10 R is the linker for connection to Ab LLA and R 11 is OH, where R LL and R LLA may be the same or different; or (iii) R 10 is a capping group RC, and R 11 is OH; (c) m is 0 or 1; (d) If there is a double bond between C2 and C3, R 2 is methyl; If there is a single bond between C2 and C3, R 2 H or

[0009] [ka] and; If there is a double bond between C2' and C3', R 12 is methyl; If there is a single bond between C2' and C3', R 12 H or

[0010] [ka] is) It is expressed as: In one embodiment, the PBD dimer has the following formula (III):

[0011] [ka] (In the formula, (a)R LL is a linker for linking to an Ab; (b)(i)R 10 and R 11 (ii) R 10 R is a linker for linking to Ab LLA and R 11 is OH; or (iii) R 10 is a capping group RC, and R 11 is OH; and (c) m is 0 or 1. It is expressed as:

[0012] In one embodiment, R LL is represented by the following formula (Ia):

[0013] [ka] (In the formula, Q:

[0014] [ka] wherein QX is such that Q is an amino acid residue, a dipeptide residue, a tripeptide residue, or a tetrapeptide residue; X is:

[0015] [ka] (In the formula, a=0 to 5, b1=0 to 16, b2=0 to 16, c1=0 or 1, c2=0 or 1, d=0 to 5, at least b1 or b2=0, and at least c1 or c2=0); G LL is a linker group attached to the antibody It is expressed as:

[0016] In one embodiment, the linker comprises a cleavable linker, including a linker comprising a cathepsin-cleavable sequence, Val-Ala or Val-Cit. In one embodiment, the PBD dimer is conjugated to an antibody at an endogenous and / or engineered N-linked glycosylation site. In one embodiment, dosing is Q3W. In one embodiment, the flat dosing is 2 or more cycles. In one embodiment, all doses are administered to the patient as a flat dosing regimen. In one embodiment, the ADC is selected from ADCT-301 (camidanlumab tesirine), ADCT-402 (loncastuximab tesirine), ADCT-601 (uzoptirine mipasetamab), ADCT-602, ADCT-701, or ADCT-901. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Flat Dosing Regimen The present disclosure provides treatment regimens in which the ADC is administered using a flat dosing regimen for one or more cycles. The term "flat dosing regimen" is used herein to refer to a dosing regimen in which the dosage is not adjusted according to the patient's body size, such as weight or body surface area. Flat dosing regimens are in contrast to "weight-based" or "surface-area-based" dosing regimens in which the dosage is adjusted to the patient's body size, and thus the dosage may vary from patient to patient. For example, in a flat dosing regimen, a 60 kg person and a 100 kg person receive the same dose of ADC. Thus, a flat dose is expressed as a mg / kg dose or mg / m 2 The dosage is not provided as a unit, but as an absolute amount of ADC. In some cases, the dosage may be expressed as mass (e.g., mg). Alternatively, the dosage may be expressed in moles. The dose of the ADC administered in each treatment cycle may be in the range of 1 to 25 mg, more preferably in the range of 2 to 20 mg. In some cases, the dose of the ADC administered in each treatment cycle may be about 1 to 5 mg, about 6 to 10 mg, about 11 to 15 mg, about 16 to 20 mg, or about 21 to 25 mg. In some cases, the dose of the ADC administered in each treatment cycle can be about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 mg. In some cases, the dose of the ADC administered in each treatment cycle is about 2.3 mg, about 4.5 mg, about 6.8 mg, about 9 mg, about 11 mg, about 14 mg, about 18 mg, or about 22 mg. The dose of the ADC administered in each treatment cycle may be within the range of 1-2 mg (e.g., about 1.9 mg). The dose of the ADC administered in each treatment cycle may be within the range of 3-4 mg (e.g., about 3.8 mg). The dose of the ADC administered in each treatment cycle may be within the range of 4-5 mg (e.g., about 4.9 mg). The dose of the ADC administered in each treatment cycle may be within the range of 5-6 mg (e.g., about 5.6 mg). The dose of the ADC administered in each treatment cycle may be within the range of 11-12 mg (e.g., about 11.3 mg).

[0018] The dose of the ADC administered in each treatment cycle can be within the range of 5 to 170 nmol, for example, about 10 to 130 nmol. In some cases, the dose of the ADC administered in each treatment cycle can be about 5 to 19 nmol, about 20 to 34 nmol, about 35 to 49 nmol, about 50 to 64 nmol, about 65 to 79 nmol, about 80 to 94 nmol, about 95 to 109 nmol, about 110 to 124 nmol, about 125 to 149 nmol, or about 150 to 170 nmol. In some cases, the dose of ADC administered in each treatment cycle can be about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, or 170 nmol. The dose of ADC administered in each treatment cycle may be within the range of 10 to 20 nmol (e.g., about 12 nmol). The dose of ADC administered in each treatment cycle may be within the range of 20 to 30 nmol (e.g., about 25 nmol). The dose of ADC administered in each treatment cycle may be within the range of 30 to 40 nmol (e.g., about 32 nmol). The dose of ADC administered in each treatment cycle may be within the range of 40 to 50 nmol (e.g., about 45 nmol). The dose of ADC administered in each treatment cycle may be within the range of 50 to 60 nmol (e.g., about 55 nmol). The dose of ADC administered in each treatment cycle may be within the range of 60 to 70 nmol (e.g., about 65 nmol). The dose of ADC administered in each treatment cycle may be within the range of 70 to 80 nmol (e.g., about 74 nmol).

[0019] The dose can also be expressed in terms of the weight (μg) of the active substance (payload), i.e., the released PBD. The molecular weight of the PBD is usually on the order of 500-700 g / mol. For example, SG3199 has a MW of 585 g / mol. Thus, since the flat dose above is based on the whole ADC, which has a MW of about 153 kDa (153,000 g / mol) due to the IgG and linker components, the flat dose for the PBDs alone (assuming two PBDs per IgG, i.e., a DAR of 2) is less than 1 / 100 of the dose for a full-sized IgG-based ADC. Thus, the dose of PBD administered as an ADC in each treatment cycle may be in the range of 5-200 μg, for example, about 10-150 μg. In some cases, the dose of PBD administered as an ADC in each treatment cycle may be about 5-20 μg, about 21-40 μg, about 41-60 μg, about 61-75 μg, about 76-90 μg, about 91-105 μg, about 105-130 μg, about 131-150 μg, about 151-175 μg, about 176-200 μg. In some cases, the dose of PBD administered in each treatment cycle as an ADC can be about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195 or 200 μg. The dose of PBD administered in each treatment cycle as an ADC may be in the range of 12-25 μg (e.g., about 17 μg). The dose of PBD administered in each treatment cycle as an ADC may be in the range of 25-35 μg (e.g., about 30 μg). The dose of PBD administered in each treatment cycle as an ADC may be in the range of 35-45 μg (e.g., about 40 μg). The dose of PBD administered in each treatment cycle as an ADC may be in the range of 45-55 μg (e.g., about 50 μg). The dose of PBD administered in each treatment cycle as an ADC may be in the range of 55-70 μg (e.g., about 62 μg). The dose of PBD administered in each treatment cycle as an ADC may be in the range of 70-90 μg (e.g., about 80 μg). The doses in nmol and / or μg provided above can also be used to calculate the dose of the total ADC in mg, where the molecular weight of the targeting moiety, linker and / or drug-to-antibody ratio (DAR) are different from an IgG-based ADC, where the DAR is 2, to ensure an equivalent dose of drug. For example, when an antibody fragment or peptide-based targeting moiety is used, the total molecular weight is significantly smaller than 153 kDa.

[0020] In one embodiment, when the ADC includes ADCT-402 (loncastuximab tesirine) or the like, the dose per cycle is about 4.5-15 mg, e.g., about 9-13 mg (e.g., about 11.25 mg) in at least the first cycle or the first two cycles, and 4.5-7 mg (e.g., about 5.625 mg) in subsequent cycles. In such cases, dosing is preferably Q3W.

[0021] In one embodiment, when the ADC includes ADCT-301 (camidanlumab tesirine), the dose per cycle is about 2-4 mg, e.g., about 3-4 mg (e.g., about 3.375 mg) for at least the first cycle or the first two cycles, and 2-2.5 mg (e.g., about 2.25 mg) for subsequent cycles. In such cases, dosing is preferably Q3W.

[0022] In one embodiment, when the ADC comprises an anti-KAAG 1 antibody, such as ADCT-901, the dose administered per cycle is about 2.3 mg, about 4.5 mg, about 6.8 mg, about 9 mg, about 11 mg, about 14 mg, about 18 mg, or about 22 mg. In such cases, dosing is preferably Q3W.

[0023] In one embodiment, when the ADC comprises an anti-AXL antibody such as ADCT-601, the dose administered per cycle is about 3.8 mg, about 7.5 mg, about 11 mg, about 13 mg, about 15 mg, about 19 mg, or about 23 mg. In such cases, dosing is preferably Q3W. In one embodiment, when such an ADC is administered in combination with gemcitabine, the ADC dose administered per cycle is about 3.8 mg, about 7.5 mg, or about 11 mg. In one embodiment, the dose of gemcitabine administered is about 540 mg / m2, about 675 mg / m2, about 800 mg / m2, or about 1000 mg / m2. The dose is usually administered twice in each cycle of ADCT-601, for example, at weekly intervals, for example, on days 1 and 8.

[0024] The flat dosing regimen may be for all or part of the treatment. The flat dosing is used in at least one treatment cycle, for example, at least two, three, four or more treatment cycles. In one embodiment, all treatment cycles are based on flat dosing, for example, all treatment cycles are at least 2, 3, or 4 months. The flat dose used may be consistent throughout the treatment, i.e., the same in each cycle until the end of treatment, or may be changed for one or more cycles from the starting dose, for example, to reduce the dose compared to the starting dose after a certain period or according to the needs of the individual patient. In some cases, each treatment cycle is 7-28 days, e.g., 20-28 days, e.g., 1, 2, 3, or 4 weeks. In some cases, each treatment cycle is 20-24 days, e.g., 3 weeks. In some cases, each treatment cycle is 4 weeks. In some cases, dosing is Q3W. In some cases, dosing is Q4W.

[0025] In one embodiment, the ADC is administered by intravenous injection. In one embodiment, it may be desirable to administer a steroid such as dexamethasone or its equivalent (e.g., prednisone) before and / or after administration of the ADC, e.g., both before and after administration. A suitable dose is 4 mg of oral (PO) dexamethasone, or its equivalent (25 mg for prednisone), twice daily. An example schedule is as follows: The day before each ADC administration ADC administration day (first dose at least 2 hours prior to dosing if not administered the previous day; otherwise, any time prior to dosing). The day after ADC administration.

[0026] antibody The term "antibody" as used herein is used in the broadest sense, and specifically includes monoclonal antibodies, including both complete antibodies and antibody fragments, so long as the monoclonal antibody exhibits the desired biological activity, e.g., tumor antigen binding ability. Antibodies may be murine, rat, human, humanized, chimeric, or derived from other species. Antibodies include full-length immunoglobulin molecules or immunologically active portions of full-length immunoglobulin molecules, i.e., molecules that contain an antigen binding site that immunospecifically binds to an antigen of a target of interest or portion thereof, including, but not limited to, cancer cells or cells that produce autoimmune antibodies associated with an autoimmune disease. The immunoglobulin may be an immunoglobulin molecule of any type (e.g., IgG, IgE, IgM, IgD, and IgA), class (e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2) or subclass, or allotype (e.g., human G1m1, G1m2, G1m3, non-G1m1 [i.e., any allotype other than G1m1], G1m17, G2m23, G3m21, G3m28, G3m11, G3m5, G3m13, G3m14, G3m10, G3m15, G3m16, G3m6, G3m24, G3m26, G3m27, A2m1, A2m2, Km1, Km2, and Km3). Various immunoglobulin variant formats derived from conventional immunoglobulins are known in the art, such as bispecific antibodies, scFvs, nanobodies, etc. All of these are within the scope of the term "antibody" as long as they retain the desired biological activity, e.g., tumor antigen binding ability.

[0027] Preferred antibodies In some embodiments, the antibody binds to KAAG1. In some embodiments, the KAAG1 polypeptide corresponds to Genbank Accession No. AAF23613 Update No. AAF23613.1. In one embodiment, the nucleic acid encoding the KAAG1 polypeptide corresponds to Genbank Accession No. AF181722 Update No. AF181722.1. The antibody may be a VH domain with a VH CDR1 represented by the amino acid sequence of SEQ ID NO: 42, a VH CDR2 represented by the amino acid sequence of SEQ ID NO: 43, and a VH CDR3 represented by the amino acid sequence of SEQ ID NO: 44. The antibody may further comprise a VL domain with a VL CDR1 represented by the amino acid sequence of SEQ ID NO: 45, a VL CDR2 represented by the amino acid sequence of SEQ ID NO: 46, and a VL CDR3 represented by the amino acid sequence of SEQ ID NO: 47. In a preferred embodiment, the antibody comprises a VH domain represented by the sequence of SEQ ID NO: 38 and a VL domain represented by the sequence of SEQ ID NO: 39, SEQ ID NO: 49, or SEQ ID NO: 51. In one embodiment, the antibody comprises a heavy chain represented by the sequence of SEQ ID NO: 40 or 48 and a light chain represented by the sequence of SEQ ID NO: 41, SEQ ID NO: 50, or SEQ ID NO: 52.

[0028] In some embodiments, the antibody binds to CD25. In some embodiments, the CD25 polypeptide corresponds to Genbank Accession No. NP_000408 Update No. NP_000408.1 GI:4557667 Record Updated on 9 Sep. 2012 at 04:59 PM. In one embodiment, the nucleic acid encoding the CD25 polypeptide corresponds to Genbank Accession No. NM_000417 Update No. NM_000417.2 GI:269973860 Record Updated on 9 Sep. 2012 at 04:59 PM. In some embodiments, the CD25 polypeptide corresponds to Uniprot / Swiss-Prot Accession No. P01589. The antibody may comprise a VH domain represented by a VH CDR1 represented by the amino acid sequence of SEQ ID NO: 3, a VH CDR2 represented by the amino acid sequence of SEQ ID NO: 4, and a VH CDR3 represented by the amino acid sequence of SEQ ID NO: 5, for example, the antibody may comprise a VH domain represented by SEQ ID NO: 1. The antibody may further comprise a VL domain represented by a VL CDR1 represented by the amino acid sequence of SEQ ID NO: 6, a VL CDR2 represented by the amino acid sequence of SEQ ID NO: 7, and a VL CDR3 represented by the amino acid sequence of SEQ ID NO: 8, for example, the antibody may comprise a VL domain represented by SEQ ID NO: 2.

[0029] In some embodiments, the antibody binds to CD19. In some embodiments, the CD19 polypeptide corresponds to Genbank Accession No. NP_001171569 Update No. NP_001171569.1 GI:296010921 Record Update Date: 10 Sep 2012 12:43 AM. In one embodiment, the nucleic acid encoding the CD19 polypeptide corresponds to Genbank Accession No. NM_001178098 Update No. NM_001178098.1 GI:296010920 Record Update Date: 10 Sep 2012 12:43 AM. In some embodiments, the CD19 polypeptide corresponds to Uniprot / Swiss-Prot Accession No. P15391. The antibody may comprise a VH domain represented by the sequence of SEQ ID NO: 9 or 10, and optionally further comprises a VL domain represented by the sequence of SEQ ID NO: 11 or 12. In a preferred embodiment, the antibody comprises a VH domain represented by SEQ ID NO:10 and a VL domain represented by SEQ ID NO:12.

[0030] In one embodiment, the antibody binds to CD22. In one embodiment, the CD22 polypeptide corresponds to Genbank Accession No. BAB15489 Update No. BAB15489.1 GI:10439338 Record Updated: 11 Sep. 2006 at 11:24 PM. In one embodiment, the nucleic acid encoding the CD22 polypeptide corresponds to Genbank Accession No. AK026467 Update No. AK026467.1 GI:10439337 Record Updated: 11 Sep. 2006 at 11:24 PM. Preferably, the antibody comprises a VH domain represented by SEQ ID NO: 13. Preferably, the antibody comprises a VL domain represented by SEQ ID NO: 14. Most preferably, the antibody comprises a heavy chain represented by SEQ ID NO: 15 and a light chain represented by SEQ ID NO: 16, and optionally a drug moiety is conjugated to the cysteine ​​at position 219 of SEQ ID NO: 15.

[0031] In some embodiments, the antibody binds to AXL. In some embodiments, the AXL polypeptide corresponds to Genbank Accession No. AAH32229 Update No. AAH32229.1gI:21619004 Record Update Date 06 Mar 2012 01:18 PM. In one embodiment, the nucleic acid encoding the AXL polypeptide corresponds to Genbank Accession No. M76125 Update No. M76125.1gI:292869 Record Update Date: 1. 23 Jun 2010 08:53 AM. In some embodiments, the antibody comprises a VH domain having a VH CDR1 represented by the amino acid sequence of SEQ ID NO:21, a VH CDR2 represented by the amino acid sequence of SEQ ID NO:22, and a VH CDR3 represented by the amino acid sequence of SEQ ID NO:23. The antibody may further comprise a VL domain represented by a VL CDR1 represented by the amino acid sequence of SEQ ID NO:24, a VL CDR2 represented by the amino acid sequence of SEQ ID NO:25, and a VL CDR3 represented by the amino acid sequence of SEQ ID NO:26. In a preferred embodiment, the antibody comprises a VH domain represented by SEQ ID NO:17 and a VL domain represented by SEQ ID NO:18.

[0032] In some embodiments, the antibody binds to DLK-1. In some embodiments, the DLK1 polypeptide corresponds to Genbank Accession No. CAA78163 Update No. CAA78163.1 Record Update Date 2 Feb. 2011 10:34 AM. In one embodiment, the nucleic acid encoding the DLK1 polypeptide corresponds to Genbank Accession No. Z12172 Update No. Z12172.1 Record Update Date 2 Feb. 2011 10:34 AM. The antibody may comprise a VH domain with a VH CDR1 represented by the amino acid sequence of SEQ ID NO: 31, a VH CDR2 represented by the amino acid sequence of SEQ ID NO: 32, and a VH CDR3 represented by the amino acid sequence of SEQ ID NO: 33. The antibody may further comprise a VL domain represented by a VL CDR1 represented by the amino acid sequence of SEQ ID NO: 34, a VL CDR2 represented by the amino acid sequence of SEQ ID NO: 35, and a VL CDR3 represented by the amino acid sequence of SEQ ID NO: 36. Preferably, the antibody comprises a VH domain represented by SEQ ID NO: 27 and a VL domain represented by SEQ ID NO: 28. In one embodiment, the antibody comprises a heavy chain represented by SEQ ID NO:29 or 37 paired with a light chain represented by SEQ ID NO:30.

[0033] The term "binds to [antigen]" as used herein to describe an antibody (e.g., "binds to KAAG1") means that the antibody binds to the antigen with higher affinity than a nonspecific partner, such as bovine serum albumin (BSA, Genbank Accession No. CAA76847 Update No. CAA76847.1 GI:3336842 Record Updated on 01 / 07 / 2011 02:30 PM). In certain embodiments, the antibody binds to the antigen with an affinity that is at least 2, 3, 4, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, 50 ... 4 , 10 5 or 10 6 The antibodies of the present disclosure can bind to an antigen with high affinity. For example, in one embodiment, the antibodies bind to an antigen with an association constant (Ka) that is about 10 times higher. -6 KD below M, e.g., 1 x 10 -6 , 10 -7 , 10 -8 , 10 -9, 10 -10 , 10 -11 , 10 -12 , 10 -13 or 10 -14 The antibody can bind to the antigen with a KD of one or less of the following: An "antibody fragment" comprises a portion of a full-length antibody, generally the antigen-binding or variable region thereof. Examples of antibody fragments include Fab, Fab', F(ab')2, and scFv fragments; diabodies; linear antibodies; fragments produced by a Fab expression library, anti-idiotypic (anti-Id) antibodies, CDRs (complementarity determining regions), and epitope-binding fragments of any of the above that immunospecifically bind to cancer cell antigens, viral antigens, or microbial antigens, single-chain antibody molecules; and multispecific antibodies formed from antibody fragments.

[0034] The term "monoclonal antibody" as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, i.e., the individual antibodies constituting the population are identical except for possible naturally occurring mutations that may be present in minor amounts. Monoclonal antibodies are highly specific and directed against a single antigenic site. Furthermore, in contrast to polyclonal antibody preparations that contain different antibodies against different determinants (epitopes), each monoclonal antibody is directed against a single determinant on the antigen. In addition to their specificity, monoclonal antibodies are advantageous in that they may be synthesized unmixed with other antibodies. The term "monoclonal" refers to the character of the antibody as being obtained from a substantially homogeneous population of antibodies and should not be construed as requiring production of the antibody by any particular method. For example, monoclonal antibodies used in accordance with the present disclosure may be produced by hybridoma techniques or by recombinant DNA techniques. Monoclonal antibodies may also be isolated from phage antibody libraries or from transgenic mice carrying a fully human immunoglobulin system. Monoclonal antibodies herein specifically include "chimeric" antibodies in which portions of the heavy and / or light chains are identical or homologous to corresponding sequences in antibodies from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chains are identical or homologous to corresponding sequences in antibodies from other species or belonging to other antibody classes or subclasses, as well as fragments of such antibodies that exhibit the desired biological activity. Chimeric antibodies include "primatized" antibodies that contain variable domain antigen-binding sequences derived from a non-human primate (e.g., Old World Monkey or Ape) and human constant region sequences. The term "complete antibody" as used herein includes VL and VH domains, as well as a light chain constant domain (CL) and a heavy chain constant domain, CH1, CH2 and CH3. The constant domains may be native sequence constant domains (e.g., human native sequence constant domains) or amino acid sequence variants thereof. A complete antibody may have one or more "effector functions" that exhibit a biological activity attributable to the Fc region of the antibody (native sequence Fc region or amino acid sequence variant Fc region). Examples of antibody effector functions include C1q binding; complement dependent cytotoxicity; Fc receptor binding; antibody-dependent cell-mediated cytotoxicity (ADCC); phagocytosis; and down-regulation of cell surface receptors such as B cell receptor and BCR.

[0035] Antibody Modifications The antibodies disclosed herein may be modified, for example, to reduce immunogenicity to a human subject. This can be accomplished using any of a number of techniques well known to those of skill in the art, including humanization to reduce the in vivo immunogenicity of non-human antibodies or antibody fragments. A variety of humanization techniques exist, including "CDR grafting", "guide selection", "deimmunization", "resurfacing" (also known as "veneering"), "composite antibodies", "human string content optimization" and framework shuffling. The antibody may be a fully human monoclonal IgG1 antibody, preferably IgG1,κ.

[0036] PBD cytotoxin Pyrrolobenzodiazepines (PBDs) suitable for use in the present disclosure, in one embodiment, function to recognize and bind to specific sequences of DNA, with the preferred sequence being PuGPu. PBDs have the following general structure:

[0037] [ka] There is. They differ in the number, type and position of substituents at their aromatic A and pyrrolo C rings and the degree of saturation of the C ring. The B ring has either an imine (N=C), a carbinolamine (NH-CH(OH)), or a carbinolamine methyl ether (NH-CH(OMe)) at the N10-C11 position, which is the electrophilic center responsible for DNA alkylation. All known natural products have an (S)-configuration at the chiral C11a position, which results in a right-handed twist when viewed from the C ring towards the A ring. This provides the appropriate three-dimensional shape for isohelicity with the minor groove of B-form DNA, resulting in a tight fit at the binding site. The ability to form adducts in the minor groove can interfere with DNA processing, making them useful as antitumor agents. The cytotoxin typically has the following formula (I):

[0038] [ka] (In the formula, R LL is a linker for attachment to an antibody, examples and specific embodiments are provided in more detail below in the section "Linkers"

[0036] The PBD dimer may be a PBD dimer such as Linker R LL When released from R LL The bond between N10 and C11, to which R was previously attached, usually forms a double bond between the nitrogen atom and the carbon atom to which they are both attached (imine (C=N)). Similarly, in the released drug, R 10 and R 11usually form a double bond between the nitrogen and carbon atoms to which they are both attached. Thus, the released drug has the following formula RelA:

[0039] [ka] It may be.

[0040] R 10 and R 11 In one embodiment, R 10 and R 11 both form a double bond between the nitrogen atom and the carbon atom to which they are attached. In other embodiments, R 10 R is a linker for connection to the antibody Ab LLA and R 11 is OH and R LLA is R LL It has the same definition as R LLA and R LL are the same or different. In other embodiments, R 10 is a capping group RC, and R 11 is OH.

[0041] Capping groups can be used to reduce or inhibit the cytotoxic activity of the PBD, effectively forming a prodrug, but in this context, not linked to a cell binding agent. The capping group is then removed, for example, in the target cell or tumor microenvironment, to activate the drug. Various capping groups are described in Franzyk and Christiansen, 2021, Molecules 26:1292. (1) Prodrugs that are cleaved in acidic media, such as salts of dithiocarbamates. (2) Prodrugs that are cleaved by reactive oxygen species. (3) Prodrugs that are cleaved by glutathione. (4) Prodrugs that are cleaved by expressed enzymes, such as oxidoreductases, hydrolases and matrix metalloproteinases. (5) Prodrugs that are cleaved by β-glucuronidase, such as RC, are converted to glucuronides, such as:

[0042] [ka] (where the square brackets indicate that the NO2 group is optional) In one embodiment, a NO2 group is present. Capping groups can also be used to modify the physicochemical properties of the antibody-drug conjugate, e.g., to make it more stable. For example, capping groups can increase the hydrophilicity of the antibody-drug conjugate. m In some embodiments, m is 0. In some embodiments, m is 1. R 2 and R 12 In one embodiment, R 2 and R 12 is the same. In one embodiment, there is a double bond between C2 and C3 and between C2′ and C3, and R 2 and R 12 Both are methyl. In one embodiment, there is a single bond between C2 and C3 and between C2′ and C3, and R 2 and R12 Both are H. In one embodiment, there is a single bond between C2 and C3 and between C2′ and C3, and R 2 and R 12 Both,

[0043] [ka] It is. In one embodiment, the drug linker LD has the following formula (II):

[0044] [ka] (In the formula, R LL , R 10 , R 11 and m has the same meaning as above. It is expressed as: In certain embodiments, R 10 and R 11 both form a double bond between the nitrogen and carbon atoms to which they are attached; m is 0 (ie, SG2000 with a linker at N10). In other embodiments, the drug linker LD has the following formula (III):

[0045] [ka] (In the formula, R LL , R 10 , R 11 and m is as defined above. It is expressed as: In one embodiment, R 10 and R 11 both form a double bond between the nitrogen and carbon atoms to which they are attached; and m is 1 (ie, SG3199 with a linker at N10).

[0046] Drug Linker A wide variety of linker technologies are available in the art for linking cytotoxins to cell-binding agents. Linkers can incorporate a variety of different moieties to contribute to the stability of antibody-drug conjugates and determine drug release properties. For example, linkers can include cleavable moieties, such as valine-alanine or valine-citrulline, which can be cleaved by cathepsin B. Another strategy is the use of pH-sensitive linkers, whereby the lower pH of endosomal and lysosomal compartments leads to hydrolysis of acid-labile groups (e.g., hydrazones) in the linker. Alternative linkers can be non-cleavable, avoiding or reducing off-target effects and improving plasma stability in circulation.

[0047] The functionality that allows conjugation to cell-binding agents is based on the site of conjugation and its chemistry. N-hydroxysuccinimide esters are a common choice for functionalizing amines, especially when coupling to ε-lysine residues. For conjugation to cysteine, thiol-reactive maleimides are the most applicable reactive handles, but disulfide bridges can also be created by oxidation with linkers that have sulfhydryl groups. Aldehydes or keto functional groups, such as oxidized sugar groups or pAcPhe unnatural amino acids, can react with hydrazides and alkoxyamines to generate acid-labile hydrazone or oxime bonds. Additionally, hydrazines can be coupled to aldehydes via HIPS ligation to generate stable CC bonds. A more recent approach is based on N-linked glycosylation sites in antibodies, such as Asn-297 in IgG molecules, using GlycoConnect™ (Synaffix), an enzyme, to trim the N-linked glycans to a GlcNAc core, followed by further enzymatic processing to introduce an azide-containing activated moiety that can then be used to incorporate drug linkers using copper-free click chemistry.

[0048] Other aspects of linker chemistry include spacers and / or moieties, such as polyethylene glycol (PEG) chains or polar functional groups such as sulfonyl, within the linker that mask the hydrophobicity of the cytotoxin payload, reduce cellular efflux mechanisms, and / or increase overall stability. In an embodiment, the antibody drug conjugate of the present disclosure may be described as Ab-LD, for example, where Ab is an anti-KAAG1 antibody, D is a PBD-containing cytotoxin, and L is a linker. The number of drug moieties per Ab (drug loading p) depends on the number of linkers attached to each Ab and the number of drug moieties per linker. Typically, drug loading p is 1-8, e.g., 1-4 or 2-4. In an embodiment, one drug moiety is attached to each linker, while in other embodiments, two or more drug moieties may be attached to each linker (e.g., branched linkers). Drug loading is usually considered on an average basis, since variation can arise from the conjugation process. Methods for determining average drug loading are known in the art.

[0049] In one embodiment, a linker (e.g., R LL ) is represented by formula (Ia):

[0050] [ka] (In the formula, Q is

[0051] [ka] wherein QX is such that Q is an amino acid residue, a dipeptide residue, a tripeptide residue or a tetrapeptide residue. X is

[0052] [ka] a=0 to 5, b1=0 to 16, b2=0 to 16, c1=0 or 1, c2=0 or 1, d=0 to 5, and at least b1 or b2=0 (i.e., only one of b1 and b2 does not have to be 0), and at least c1 or c2=0 (i.e., only one of c1 and c2 does not have to be 0). G LL is a linker group linked to the Ab; Q X In one embodiment, Q is an amino acid residue. The amino acid may be a natural amino acid or an unnatural amino acid. It is expressed as: In one embodiment, Q is selected from Phe, Lys, Val, Ala, Cit, Leu, Ile, Arg, and Trp, where Cit is citrulline. In one embodiment, Q comprises a dipeptide residue. The amino acids in the dipeptide can be any combination of natural and non-natural amino acids. In some embodiments, the dipeptide comprises natural amino acids. When the linker is a cathepsin-labile linker, the dipeptide is the site of action for cathepsin-mediated cleavage. The dipeptide is the recognition site for cathepsin. In one embodiment, Q is:

[0053] [ka] wherein Cit is citrulline. Preferably, Q is one of the following:

[0054] [ka] is selected from. Most preferably, Q is one of the following:

[0055] [ka] is selected from. Other interesting dipeptide combinations include: below:

[0056] [ka] Examples include: Other dipeptide combinations may be used, including those described in Dubowchik et al., Bioconjugate Chemistry, 2002, 13, 855-869, incorporated herein by reference. In some embodiments, Q is a tripeptide residue. The amino acids in the tripeptide can be any combination of natural and unnatural amino acids. In some embodiments, the tripeptide comprises natural amino acids. When the linker is a cathepsin-labile linker, the tripeptide is the site of action for cathepsin-mediated cleavage. The tripeptide is the recognition site for cathepsin. Tripeptide linkers of particular interest are the following:

[0057] [ka] and

[0058] [ka] It is expressed as: In the above representation of peptide residues, NH represents the N-terminus and -C=O represents the C-terminus of the residue, which is attached to an NH attached to a benzene ring. Glu is:

[0059] [ka] Represents a glutamic acid residue. αGlu is the following:

[0060] [ka] It represents a glutamic acid residue when bound via the α chain. In one embodiment, the amino acid side chains are chemically protected, if appropriate. The side chain protecting groups can be those discussed above. The protected amino acid sequence is enzymatically cleavable. For example, a dipeptide sequence containing a Boc side chain protected Lys residue is cleavable by cathepsin. Protecting groups for the side chains of amino acids are well known in the art and are described in the Novabiochem Catalog and as discussed above.

[0061] G LL G LL may be selected from the following:

[0062] [ka] wherein Ar represents a C5-6 arylene group, e.g., phenylene, and X represents a C1-4 alkyl. CBA represents a G linked to an antibody. LL Indicates the end of. In one embodiment, G LL is G LL 1-1 and G LL In some of these embodiments, G LL is G LL The score is 1-1. In another embodiment, G LL is G LL 10 and G LL In certain of these embodiments, G is selected from LL is G LL It is 10.

[0063] C 5-6 Arylene: As used herein, the term "C 5-6 "Arylene" refers to a divalent moiety obtained by removing two hydrogen atoms from an aromatic ring atom of an aromatic compound. In this context, prefixes (e.g., C 5-6 ) indicates the number of ring atoms, whether carbon atoms or heteroatoms, or range of number of ring atoms. The ring atoms may be all carbon atoms, such as in a "carbarylene group," in which case the group is phenylene (C6). Alternatively, the ring atoms may contain one or more heteroatoms, such as in a "heteroarylene group." Examples of heteroarylene groups include, but are not limited to, those derived from: N1: Pyrrole (azole) (C5), pyridine (azine) (C6); O1: furan(oxoyl)(C5); S1: Thiophene (thiol) (C5) N1O1: oxazole (C5), isoxazole (C5), isoxazine (C6); N2O1: oxadiazole (furazan) (C5); N3O1: oxatriazole (C5); N1S1: thiazole (C5), isothiazole (C5); N2: imidazole (1,3-diazole) (C5), pyrazole (1,2-diazole) (C5), pyridazine (1,2-diazine) (C6), pyrimidine (1,3-diazine) (C6) (e.g., cytosine, thymine, uracil), pyrazine (1,4-diazine) (C6); and N3: Triazole (C5), triazine (C6).

[0064] C 1-4 Alkyl: The term "C1-4 alkyl" as used herein refers to a monovalent moiety obtained by removing a hydrogen atom from a carbon atom of a hydrocarbon compound having 1 to 4 carbon atoms, which may be aliphatic or alicyclic, and may be saturated or unsaturated (e.g., partially unsaturated, fully unsaturated). The term "C1-n alkyl" as used herein refers to a monovalent moiety obtained by removing a hydrogen atom from a carbon atom of a hydrocarbon compound having 1 to n carbon atoms, which may be aliphatic or alicyclic, and may be saturated or unsaturated (e.g., partially unsaturated, fully unsaturated). Thus, the term "alkyl" includes the subclasses alkenyl, alkynyl, cycloalkyl, etc., described below.

[0065] X X is:

[0066] [ka] (wherein a=0 to 5, b1=0 to 16, b2=0 to 16, c1=0 or 1, c2=0 or 1, d=0 to 5, at least b1 or b2=0, and at least c1 or c2=0). a can be 0, 1, 2, 3, 4, or 5. In some embodiments, a is 0 to 3. In some of these embodiments, a is 0 or 1. In further embodiments, a is 0. In further embodiments, a is 1. b1 can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16. In some embodiments, b1 is 0 to 12. In some of these embodiments, b1 is 0 to 8, and may be 0, 2, 3, 4, 5, or 8. In further embodiments, b1 is 2. b2 can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16. In some embodiments, b2 is 0 to 12. In some of these embodiments, b2 is 0 to 8, and may be 0, 2, 3, 4, 5, or 8. In further embodiments, b2 is 8. Only one of b1 and b2 may not be 0. c1 can be 0 or 1. c2 can be 0 or 1. Only one of c1 and c2 may not be 0. d can be 0, 1, 2, 3, 4, or 5. In some embodiments, d is 0 to 3. In some of these embodiments, d is 1 or 2. In further embodiments, d is 2. In further embodiments, d is 5. In some embodiments of X, a is 0, b1 is 0, c1 is 1, c2 is 0, d is 2, and b2 can be 0 to 8. In some of these embodiments, b2 is 0, 2, 3, 4, 5, or 8. In further embodiments, b2 is 8. In some embodiments of X, a is 1, b2 is 0, c1 is 0, c2 is 1, d is 2, and b1 can be 0 to 8. In some of these embodiments, b1 is 0, 2, 3, 4, 5, or 8. In further embodiments, b1 is 2. The linker is typically R in the following example embodiment: LL As shown in position N10, it is connected to the PBD dimer.

[0067] Drug Linker Embodiments In certain embodiments, the drug linker, L D , is selected from the following:

[0068] [ka] In the formula, R LL and R LLA is as stated above.

[0069] In certain embodiments, LD is selected from the following:

[0070] [ka] Conjugation Sites and Drug Loading Drug linkers can be conjugated to cell-binding agents, such as antibodies, at several different sites using a variety of methods known in the art. Conjugation sites include cysteine ​​and lysine residues in the sequence (endogenous or engineered), as well as sites of N-linked glycosylation after trimming (e.g., GlycoConnect™ or GlyClick™ approaches). Thus, in one embodiment, the drug linker is conjugated via a trimmed Asn-GlcNAc residue at the endogenous N-linked glycosylation site (Asn-297) typically in antibodies. With regard to cysteine ​​conjugation, in one embodiment, the cysteine ​​is an endogenous cysteine ​​located in the hinge region or Fc domain. In other embodiments, the cysteine ​​in the engineered cysteine ​​is introduced into the hinge region or Fc domain.

[0071] Drug loading is the average number of PBD drugs per cell-binding agent, eg, antibody. The average number of drugs per antibody in a preparation of ADC from a conjugation reaction can be characterized by conventional means such as UV, reversed-phase HPLC, HIC, mass spectrometry, ELISA assay, and electrophoresis. The quantitative distribution of ADCs in terms of p can also be determined. The average value of p in a particular preparation of ADC can be determined by ELISA (Hamblett et al. (2004) J. Clin. Cancer Res. 10:7063-7070; Sanderson et al. (2005) J. Clin. Cancer Res. 11:843-852). However, the distribution of p(drug) values ​​cannot be distinguished by the detection limits of antibody-antigen binding and ELISA. Also, ELISA assays for detection of antibody-drug conjugates do not determine where the drug moiety is attached to the antibody, e.g., the heavy or light chain fragment, or the specific amino acid residue. In some instances, separation, purification, and characterization of homogeneous ADCs with a particular value of p from ADCs with other drug loadings can be achieved by means such as reversed-phase HPLC or electrophoresis. The technique is also applicable to other types of conjugates. For some antibody-drug conjugates, p may be limited by the number of binding sites on the antibody. For example, an antibody may have only one or several cysteine ​​thiol groups, or only one or several sufficiently reactive thiol groups to which a linker can be attached. When the drug loading is higher, for example, p>5, certain antibody-drug conjugates may lose aggregation, insolubility, toxicity, or cell permeability. Usually, less than the theoretical maximum drug moiety is conjugated to the antibody during the conjugation reaction. The antibody may contain many lysine residues that do not react with, for example, the drug linker intermediate or linker reagent. Only the most reactive lysine groups can react with amine-reactive linker reagents. Also, only the most reactive cysteine ​​thiol groups can react with thiol-reactive linker reagents. In general, the antibody does not contain many, if any, free and reactive cysteine ​​thiol groups that can be linked to the drug moiety. Most cysteine ​​thiol residues in the antibody of the compound exist as disulfide bridges and must be reduced with a reducing agent such as dithiothreitol (DTT) or TCEP under partial or total reducing conditions. The loading (drug / antibody ratio) of the ADC can be controlled in several different ways, including (i) limiting the molar excess of the drug linker intermediate or linker reagent relative to the antibody, (ii) limiting the conjugation reaction time or temperature, and (iii) partial or limited reducing conditions for cysteine ​​thiol modification.

[0072] Some antibodies have reducible interchain disulfides, i.e., cysteine ​​bridges. Antibodies can be made reactive for conjugation with linker reagents by treatment with a reducing agent such as DTT (dithiothreitol). Each cysteine ​​bridge thus theoretically forms two reactive thiol nucleophilic groups. Additional nucleophilic groups can be introduced into antibodies via reaction of lysine with 2-iminothiolane (Traut's reagent), resulting in conversion of an amine to a thiol. Reactive thiol groups can be introduced into antibodies (or fragments thereof) by engineering one, two, three, four, or more cysteine ​​residues (e.g., by preparing a mutant antibody containing one or more non-natural cysteine ​​amino acid residues). U.S. Patent No. 7,521,541 teaches engineering antibodies by introduction of reactive cysteine ​​amino acids. Cysteine ​​amino acids can be engineered at reactive sites in antibodies and do not form intrachain or intermolecular disulfide bonds (U.S. Pat. No. 7,521,541; U.S. Pat. No. 7,723,485; WO 2009 / 052249). The engineered cysteine ​​thiol can react with a linker or drug linker reagent of the present disclosure that has a thiol-reactive electrophilic group, such as a maleimide or α-haloamide, to form an ADC with a cysteine ​​engineered antibody and a PBD drug moiety. Thus, the location of the drug moiety can be designed, controlled, and known. The engineered cysteine ​​thiol group usually reacts with a thiol-reactive linker or drug linker reagent in high yield, allowing for controlled drug loading. Engineering an IgG antibody to introduce a cysteine ​​amino acid by substitution at a single site on the heavy or light chain results in two new cysteines on a symmetric antibody.

[0073] In some embodiments, the antibody may be modified to have reactive groups present (e.g., azide). In this case, p is limited by the number of binding sites on the antibody, i.e., the number of azide groups. For example, an antibody may have only one or two azide groups to which a drug linker may be attached. When two or more nucleophilic or electrophilic groups on an antibody react with a drug-linker intermediate, or linker reagent, followed by a drug moiety reagent, the resulting product is a mixture of ADC compounds with a distribution of drug moieties attached to the antibody, e.g., 1, 2, 3, etc. Liquid chromatography methods such as polymeric reversed phase (PLRP) and hydrophobic interaction (HIC) can separate compounds in a mixture by drug loading value. Although preparations of ADCs with a single drug loading value (p) can be isolated, these single loading value ADCs can still be heterogeneous mixtures because the drug moieties can be attached to different sites on the antibody via the linker.

[0074] Thus, the antibody drug conjugate compositions of the disclosure include a mixture of antibody drug conjugate compounds, where the antibody has one or more PBD drug moieties, and the drug moieties may be attached to the antibody at various amino acid residues. In one embodiment, the average number of dimeric pyrrolobenzodiazepine groups per antibody ranges from 1 to 8. In certain embodiments, the range is selected from 1 to 4, 2 to 4, and 1 to 3. In certain embodiments, there are one or two dimeric pyrrolobenzodiazepine groups per antibody. When there are two linking groups in LD, they are preferably to the same antibody. In some of these embodiments, only one LD is attached to each antibody, so the drug loading is one.

[0075] Preparation of drug conjugates The antibody drug conjugates of the disclosure may comprise a drug linker, such as the following:

[0076] [ka] It can be prepared by conjugating a drug linker (formula (I) defined above) to an antibody. As described above, (i) the method described in, for example, U.S. Pat. No. 9,889,207 or Flynn et al., 2016. Mol Cancer Ther 15:2709--as applicable to compound C2 below; and (ii) via chemoenzymatically trimmed N-linked glycosylation sites, e.g., Asn-297 or equivalent, using GlyClick or GlycoConnect, e.g., after use of EndoS to trim glycan isoforms bearing azide groups to the core GlcNAc, as described in WO 2018 / 146188, enzymatically transferred N-acetylgalactose (GalNAc) residues to the core GalNAc for conjugation to a drug linker, typically using galactose transferase (GalT) or galactose-N-acetyltransferase (GalNAcT) enzymes. When a GalT enzyme is used, preferably the enzyme incorporates Y289L and / or C342T. Finally, the drug linker is reacted with the azide group using copper-free click chemistry, such as the method described in van Geel, R., et al., Bioconjugate Chemistry, 2015, 26, 2233-2242. This method is applicable to compound C1 below. For drug linkers, see, e.g., Tibergien et al., 2016, ACS Med. Chem. Lett. 7:983-987, WO 2014 / 057074, WO 2018 / 069490, and WO 2018 / 146188. In particular, the following table provides references for each of the drug linkers of particular interest.

[0077] [Table 1] Preferred PBD Agent ADCx25 ADCx25 has the following chemical structure:

[0078] [ka] There is. Here, "Ab" is antibody AB12 (a fully human monoclonal IgG1, kappa antibody with VH and VL sequences as set forth in SEQ ID NO:1 and SEQ ID NO:2, respectively, also known as HuMax-TAC), which was synthesized as described in WO 2014 / 057119 (Conj AB12-E) and typically has a DAR (drug to antibody ratio) of 2.0+ / -0.3.

[0079] ADCx19 ADCx19 has the chemical structure shown above for ADCx25, except that ADCx19 "Ab" refers to the antibody RB4v1.2 (an antibody having the VH and VL sequences set forth in SEQ ID NO:10 and SEQ ID NO:12, respectively), which is synthesized as described in WO 2014 / 057119 (Conj AB12-E) and typically has a DAR (drug to antibody ratio) of 2.0+ / -0.3.

[0080] ADCx22 ADCx22 has the chemical structure shown above for ADCx25, except that the "Ab" in ADCx22 represents EMabC220. This antibody comprises a heavy chain having the sequence represented by SEQ ID NO:15 and a light chain having the sequence represented by SEQ ID NO:16. Linkage to the drug occurs on the heavy chain interchain cysteine ​​Cys220 (EU numbering). HC220 corresponds to position 219 of SEQ ID NO:15. Note that "having the sequence" is synonymous with "comprising the sequence"; in particular, in one embodiment, the heavy chain of ADCx22 is expressed with an additional terminal "K" residue (thus ending in ...SPGK), which terminal K is optionally removed post-translationally to improve homogeneity of the final therapeutic ADC product.

[0081] ADCxAXL ADCxAXL has the following chemical structure: Ab-(DL)p (Wherein DL is compound B1, Ab is an antibody that binds to AXL, The antibodies are as follows: (a) a heavy chain having a sequence represented by SEQ ID NO: 17; (b) a light chain having a sequence represented by SEQ ID NO: 18) There is. Note that "having a sequence" has the same meaning as "comprising a sequence." In particular, in certain embodiments, the heavy chain of ADCxAXL is expressed with an additional terminal "K" group (thus terminating in .SPGK), and the terminal K is optionally removed post-translationally to improve homogeneity of the final therapeutic ADC product. DL may be conjugated to the antibody via the side chain of asparagine at position 302 of SEQ ID NO: 19. The structure of the linkage to the antibody may be N-[GlcNAc]-DL, where N is an asparagine residue and [GlcNAc] represents a GlcNAc residue. p may be up to 2, and is usually greater than 1.7, 1.8 or 1.9. The GlcNAc group is usually attached to the remainder of the drug linker by the GlycoConnect process as described above, in which case there may be an additional GalNAc group between the GlcNAc and the remainder of the DL shown in B1.

[0082] ADCxDLK1 ADCxDLK1 has the above chemical structure for ADCxAXL, except that in ADCxDLK1, "Ab" is an antibody that binds to DLK-1Ab, and the antibody has the following structure: (a) a heavy chain having a sequence represented by SEQ ID NO: 27; (b) a light chain having a sequence represented by SEQ ID NO: 28 Includes.

[0083] ADCxKAAG1 ADCxKAAG1 has the above chemical structure for ADCxAXL, where "Ab" is an antibody that binds to KAAG1, and the antibody has the following structure: (a) a heavy chain having a sequence represented by SEQ ID NO: 38; (b) a light chain having a sequence represented by SEQ ID NO: 39 Includes. In particularly preferred embodiments, the PBD agent is selected from ADCT-301, ADCT-402, ADCT-602, ADCT-601, ADCT-701, or ADCT-901.

[0084] Disorders Treated The dosing regimens described herein can be used for the treatment of proliferative disorders. The term "proliferative disorder" refers to undesired or uncontrolled cell proliferation of unwanted, excessive or abnormal cells, such as neoplastic or hyperplastic growth, either in vitro or in vivo. Examples of proliferative conditions include benign, premalignant, and malignant cell proliferations, such as neoplasms and tumors (e.g., histocytoma, glioma, astrocyoma, osteoma), cancer (e.g., lung cancer, small cell lung cancer, gastrointestinal cancer, intestinal cancer, colon cancer, breast cancer, ovarian cancer, prostate cancer, testicular cancer, liver cancer, kidney cancer, bladder cancer, pancreatic cancer, brain cancer, sarcoma, osteosarcoma, Kaposi's sarcoma, melanoma), lymphoma, leukemia, psoriasis, bone disease, fibroproliferative disorders (e.g., of connective tissue), and atherosclerosis. Cancers of interest include, but are not limited to, leukemia and ovarian cancer. Any cell may be treated, including, but not limited to, lung, gastrointestinal (including, e.g., intestine, colon), breast (mammary), ovary, prostate, liver (hepatic), kidney (renal), bladder, pancreas, brain, and skin. The target proliferating cells may be all or part of a solid tumor. The disorder to be treated may be or be characterized by an advanced solid tumor. "Solid tumors" herein are understood to include solid hematological cancers such as lymphomas (Hodgkin's or non-Hodgkin's lymphomas).

[0085] Generally, the disease or disorder to be treated is a hyperproliferative disease, such as cancer. Examples of cancers to be treated herein include, but are not limited to, carcinoma, lymphoma, blastoma, sarcoma, and leukemia or lymphoid malignancies. More specific examples of such cancers include squamous cell carcinoma (e.g., epithelial squamous cell carcinoma), lung cancer, including small cell lung cancer, non-small cell lung cancer, adenocarcinoma of the lung and squamous cell carcinoma of the lung, cancer of the peritoneum, hepatocellular carcinoma, gastric cancer, including gastrointestinal cancer, pancreatic cancer, glioblastoma, cervical cancer, ovarian cancer, liver cancer, bladder cancer, hepatic cancer, breast cancer, colon cancer, rectal cancer, colorectal cancer, endometrial cancer, or uterine cancer, salivary gland cancer, kidney cancer, prostate cancer, vulvar cancer, thyroid cancer, liver cancer, anal cancer, penile cancer, and head and neck cancer. Further examples of cancers to be treated herein include, but are not limited to, diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), Burkitt's lymphoma (BL), mantle cell lymphoma (MCL), chronic lymphocytic leukemia (CLL), non-Hodgkin's lymphomas including Waldenstrom's microglobulinemia, Burkitt's lymphoma, and marginal zone B-cell lymphoma (MZBL), as well as leukemias such as hairy cell leukemia (HCL), hairy cell leukemia variant (HCL-v), and acute lymphoblastic leukemia (ALL), such as Philadelphia chromosome positive ALL (Ph+ALL) or Philadelphia chromosome negative ALL (Ph-ALL).

[0086] The disease may be resistant, recurrent, or refractory. As used herein, recurrent disease constitutes a state in which a previously treated tumor that is undetectable by conventional imaging techniques becomes detectable again; refractory disease constitutes a state in which the cancer continues to grow despite anti-tumor therapy. In certain embodiments in which the ADC targets AXL, the cancer is selected from (i) sarcoma, such as soft tissue sarcoma (e.g., leiomyosarcoma, liposarcoma, undifferentiated pleomorphic sarcoma (UPS), and synovial sarcoma), and osteosarcoma (e.g., Ewing's sarcoma, osteosarcoma, and chondrosarcoma); and (ii) ovarian / fallopian tube / primary peritoneal cancer, pancreatic cancer, bladder cancer, cervical cancer, and endometrial cancer. In certain embodiments in which the ADC targets KAAG1, the cancer is selected from cholangiocarcinoma, ovarian / fallopian tube cancer, prostate cancer, renal cell carcinoma, and triple-negative breast cancer.

[0087] Subject Selection In some aspects, subjects are selected prior to treatment as suitable for treatment with the methods described herein. In some embodiments, the methods described herein include a step of selecting a suitable subject. In some embodiments, the treatment methods described herein treat subjects previously selected as suitable for treatment. As used herein, a subject believed to be suitable for treatment is one who is expected to benefit from or respond to the treatment. The individual may have, be suspected of, or be at risk for cancer. The individual may have been diagnosed with cancer. Typically, the individual is an animal or human subject. In some aspects, the individual is selected based on the amount or pattern of expression of the first target protein, hi some aspects, the selection is based on expression of the first target protein on the cell surface. In one embodiment, the first target protein is selected from CD19, CD22, CD25, AXL, DLK-1, and KAAG1.

[0088] In some cases, the individual is selected based on having been diagnosed with a proliferative disease that may have, may be suspected of, or may be at risk of having, cancer, or is characterized by the presence of a neoplasm that includes cells with high levels of surface expression of a first target protein. The neoplasm may be composed of cells with high levels of surface expression of a first target protein. In some cases, high levels of surface expression means that the average number of antibodies that specifically bind to the first target protein bound per neoplastic cell is greater than 70,000, e.g., greater than 80,000, greater than 90,000, greater than 100,000, greater than 110,000, greater than 120,000, greater than 130,000, greater than 140,000, or greater than 150,000. In some cases, the individual is selected based on having been diagnosed with a proliferative disease characterized by the presence of a neoplasm that may have, may be suspected of, or may be at risk of having, cancer, or that includes cells that have a low level of surface expression of a first target protein. The neoplasm may be composed of cells that have a low level of surface expression of a first target protein. In some cases, a low level of surface expression means that the average number of antibodies that specifically bind to the bound first target protein per neoplastic cell is less than 20,000, such as less than 80,000, less than 70,000, less than 60,000, less than 50,000, less than 40,000, less than 30,000, less than 20,000, less than 10,000, or less than 5,000. In some cases, expression of a first target protein in a particular tissue of interest is determined, for example in a tumor tissue sample. In some cases, systemic expression of the target is determined, for example in a circulating fluid sample such as blood, plasma, serum, or lymph.

[0089] In some aspects, individuals are selected as suitable for treatment due to the presence or absence of expression of a first target protein in a sample, in which case individuals in which the first target protein is not expressed may be considered unsuitable for treatment. In other embodiments, the expression level of the first target protein is used to select individuals suitable for treatment: if the expression level of the first target protein exceeds a threshold level, the individual is determined to be suitable for treatment. In some embodiments, the presence of the first target protein in cells in the sample indicates that the individual is suitable for treatment with the ADC disclosed herein. In other embodiments, the expression level of the first target protein must exceed a threshold level to indicate that the individual is suitable for treatment. In some embodiments, the observation that the localization of the first target protein is altered in the sample compared to the control indicates that the individual is suitable for treatment. In some embodiments, a patient is determined to be suitable for treatment if at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or more of the total cells in the sample express the first target protein. In some embodiments disclosed herein, a patient is determined to be suitable for treatment if at least 10% of the cells in the sample express the first target protein. In some embodiments, a patient is determined to be suitable for treatment if at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or more of the total cells in the sample express the second target protein. In some embodiments disclosed herein, a patient is determined to be suitable for treatment if at least 10% of the cells in the sample express the second target protein.

[0090] In some embodiments, the sample is taken from a bodily fluid, more preferably a bodily fluid circulating in the body. Thus, the sample may be a blood sample or a lymphatic sample. In some cases, the sample is a urine sample or a saliva sample. In certain aspects, the sample is a blood sample or a blood-derived sample. A blood-derived sample may be a selected fraction of an individual's blood, such as a selected cell-containing fraction or a plasma or serum fraction. The selected cell-containing fraction may contain cell types of the subject, which may include white blood cells (WBCs), in particular peripheral blood mononuclear cells (PBCs) and / or granulocytes, and / or red blood cells (RBCs). Thus, the method according to the present disclosure may include detection of a first target polypeptide or nucleic acid in blood, white blood cells, peripheral blood mononuclear cells, granulocytes and / or red blood cells. In other embodiments, the sample is a solid tissue biopsy. The sample may be fresh or archived. For example, archived tissue may be from a biopsy at the individual's initial diagnosis or at the time of recurrence. In some embodiments, the sample is a fresh biopsy. The terms "subject," "patient," and "individual" are used interchangeably herein. In certain embodiments disclosed herein, an individual is identified as having, suspected of having, or at risk for a proliferative disease such as cancer. In certain embodiments disclosed herein, the individual has already been diagnosed with the disease. A list of relevant diseases is provided above. In certain embodiments in which the ADC targets AXL, the subject's tumor has cells with an amplified AXL gene.

[0091] Treatment method The term "treatment" as used herein in the context of treating a condition generally relates to treatments and therapies, whether in humans or animals (e.g., in veterinary applications), in which some desired therapeutic effect is achieved, such as inhibition of progression of the condition, including slowing the rate of progression, halting the rate of progression, regressing the condition, ameliorating the condition, and curing the condition. Included is treatment as a prophylactic measure (i.e., prevention, prophylaxis). The term "therapeutically effective amount" or "effective amount" as used herein relates to an amount of an active compound, or a material, composition or dosage form containing an active compound, that is effective to produce some desired therapeutic effect, commensurate with a reasonable benefit / risk ratio, when administered in accordance with a desired treatment regimen. Similarly, the term "prophylactically effective amount" as used herein relates to an amount of active compound, or a material, composition or dosage form containing an active compound, that is effective for producing some desired prophylactic effect, commensurate with a reasonable benefit / risk ratio, when administered in accordance with a desired treatment regimen. Specific dosing regimens, including information regarding dosage amounts and intervals, are described in detail above in the "Flat Dosing Regimens" section.

[0092] Methods of treatment are disclosed herein. Methods of treatment are also provided, comprising administering a therapeutically effective amount of ADC to a subject in need of treatment. The term "therapeutically effective amount" is an amount sufficient to show benefit to the subject. The benefit may be at least an improvement in at least one symptom. The actual amount administered, as well as the rate and time course of administration, will depend on the nature and severity of what is being treated. Prescribing treatment, e.g., determining dosage, is within the responsibility of general practitioners and other medical doctors. Subjects may be tested to determine eligibility to receive treatment according to the methods disclosed herein. Methods of treatment may include using the methods disclosed herein to determine whether a subject is eligible for treatment. Treatment may involve administration of the ADC alone or in combination with other therapies, either simultaneously or sequentially, depending on the condition being treated. Examples of procedures and therapies include, but are not limited to, chemotherapy (e.g., administration of active agents including drugs such as chemotherapeutic agents); surgery; and radiation therapy.

[0093] A "chemotherapeutic agent" is a compound useful in the treatment of cancer, regardless of mechanism of action. Classes of chemotherapeutic agents include, but are not limited to, alkylating agents, antimetabolites, spindle poison plant alkaloids, cytotoxic / antitumor antibiotics, topoisomerase inhibitors, antibodies, photosensitizers, and kinase inhibitors. Chemotherapeutic agents include compounds used in "targeted therapy" and conventional chemotherapy. Additionally, the term "chemotherapeutic agent" is defined as: (i) antihormonal agents that act to regulate or inhibit hormone action on tumors, such as antiestrogens and selective estrogen receptor modulators (SERMs); (ii) aromatase inhibitors that inhibit the enzyme aromatase, which regulates estrogen production in the adrenal glands; (iii) antiandrogens; (iv) protein kinase inhibitors, such as MEK inhibitors; (v) lipid kinase inhibitors; and (vi) antiangiogenic agents. Also included within the definition of "chemotherapeutic agent" are therapeutic antibodies.

[0094] In certain embodiments in which the ADC targets AXL, the ADC is administered as a combination therapy with gemcitabine - see the "Flat Dosing Regimens" section for information regarding dosing levels and intervals.

[0095] The compositions according to the present disclosure are preferably pharmaceutical compositions. Pharmaceutical compositions according to and for use in accordance with the present disclosure may contain, in addition to the active ingredient, i.e., the conjugate compound, pharma- ceutically acceptable excipients, carriers, buffers, stabilizers, or other materials known to those skilled in the art. Such materials should be non-toxic and should not interfere with the efficacy of the active ingredient. The exact nature of the carrier or other materials will depend on the route of administration, usually by injection, e.g., cutaneous, subcutaneous, or intravenous. For intravenous, cutaneous or subcutaneous injection, or injection into the affected area, the active ingredient is in the form of a pyrogen-free parenterally acceptable aqueous solution having suitable pH, isotonicity and stability. Those skilled in the art are well able to prepare suitable solutions using isotonic vehicles such as, for example, Sodium Chloride Injection, Ringer's Injection, Lactated Ringer's Injection, etc. Preservatives, stabilizers, buffers, antioxidants and / or other additives may be included as necessary.

[0096] Specific embodiments 1. A method of treating a proliferative disorder in a subject, comprising administering to the subject an ADC, e.g., an ADC comprising a PBD dimer, wherein the ADC is administered to the subject using a flat dosing regimen for one or more cycles. 2. The method of claim 1, wherein the dose of ADC administered is 1-25 mg. 3. The method of claim 1, wherein the dose of ADC administered is 2-20 mg. 4. The method of claim 1, wherein the dose of ADC administered is 1-5 mg. 5. The method of claim 1, wherein the dose of ADC administered is 6-10 mg. 6. The method of claim 1, wherein the dose of ADC administered is 11-15 mg. 7. The method of claim 1, wherein the dose of ADC administered is 16-20 mg. 8. The method of claim 1, wherein the dose of ADC administered is 21-25 mg. 9. The method of claim 1, wherein the dose of ADC administered is 1 to 2 mg (e.g., about 1.9 mg). 10. The method of claim 1, wherein the dose of ADC administered is 3 to 4 mg (e.g., about 3.8 mg). 11. The method of claim 1, wherein the dose of ADC administered is 4-5 mg (e.g., about 4.9 mg). 12. The method of claim 1, wherein the dose of ADC administered is 5-6 mg (e.g., about 5.6 mg). 13. The method of claim 1, wherein the dose of ADC administered is 11 to 12 mg (e.g., about 11.3 mg). 14. The method of any one of statements 1-13, wherein the ADC is administered to the subject using a single cycle of a flat dosing regimen. 15. The method of any one of statements 1-13, wherein the ADC is administered to the subject using a two-cycle flat dosing regimen. 16. The method of any one of statements 1-13, wherein the ADC is administered to the subject using a three-cycle flat dosing regimen. 17. The method of any one of statements 1-13, wherein the ADC is administered to the subject using a flat dosing regimen for 4 or more cycles. 18. The method of any of the preceding statements, wherein each treatment cycle is 1 week, 2 weeks, 3 weeks, or 4 weeks. 19. The method according to any of the preceding statements, wherein the ADC is administered on a Q3W dosing regimen. 20. The method according to any of the preceding claims, wherein the PDB dimer is represented by formula (I) as defined above. 21. A method according to any of the preceding claims, wherein the antibody specifically binds to a tumor antigen. 22. A method according to any of the preceding claims, wherein the antibody specifically binds to CD19, CD22, CD25, AXL, KAAG1 or DLK-1. 23. The method according to any of the preceding claims, wherein the ADC is ADCx25, ADCx19, ADCx22, ADCxAXL, ADCxDLK1 or ADCxKAAG1. 24. The method of any of the preceding claims, wherein the ADC is ADCT-301, ADCT-402, ADCT-601, ADCT-602, ADCT-701, or ADCT-901. 25. The method of any of the preceding statements, e.g., wherein the ADC is ADCxAXL or ADCT-601, and the ADC is administered as a combination therapy with gemcitabine, e.g., based on any of the dosage levels and dosing intervals set forth in Table 2. 26. The method of any of the preceding statements, wherein the proliferative disorder is cancer. 27. The method of statement 26, wherein the cancer is ovarian cancer. 28. The method of statement 26, wherein the cancer is prostate cancer. 29. The method of claim 26, wherein the cancer is breast cancer, optionally triple-negative breast cancer. 30. The method of statement 26, e.g., wherein the ADC is ADCxAXL or ADCT-601, and the cancer is selected from (i) sarcomas, such as soft tissue sarcomas (e.g., leiomyosarcoma, liposarcoma, undifferentiated pleomorphic sarcoma (UPS), and synovial sarcoma), and osteosarcomas (e.g., Ewing's sarcoma, osteosarcoma, and chondrosarcoma); and (ii) ovarian / fallopian tube / primary peritoneal cancer, pancreatic cancer, bladder cancer, cervical cancer, and endometrial cancer. 31. A method according to any of the preceding statements, wherein the patient's tumor has cells with an amplified AXL gene. 32. The method of statement 26, wherein the antibody specifically binds to KAAG1 and the cancer is selected from cholangiocarcinoma, ovarian / fallopian tube cancer, prostate cancer, renal cell carcinoma and triple-negative breast cancer. 33. An ADC as defined in any one of statements 20-24 for use in a method according to any of the preceding statements.

[0097] Description of sequence listing CD25 SEQ ID NO:1 (AB12 VH):

[0098] [ka] SEQ ID NO:2 (AB12 VL):

[0099] [ka] CD19 SEQ ID NO:9 (RB4v1.0 VH):

[0100] [ka] SEQ ID NO:10 (RB4v1.2 VH):

[0101] [ka] SEQ ID NO:11 (RB4v1.0 VL):

[0102] [ka] SEQ ID NO: 12 (RB4v1.2 VL)

[0103] [ka] CD22 SEQ ID NO: 13 (Epratuzumab VH):

[0104] [ka] SEQ ID NO: 14 (Epratuzumab VL):

[0105] [ka] SEQ ID NO:15 (EMabC220 HC):

[0106] [ka] SEQ ID NO:16 (EMabC220-LC):

[0107] [ka] AXL SEQ ID NO:17[1H12 VH]

[0108] [ka] SEQ ID NO:18 [1H12 VL]

[0109] [ka] SEQ ID NO: 19 [1H12 heavy chain]

[0110] [ka] SEQ ID NO:20 [1H12 light chain]

[0111] [ka] DLK-1 SEQ ID NO: 27 [HuBa-1-3d VH]

[0112] [ka] SEQ ID NO: 28 [HuBa-1-3d VL]

[0113] [ka] SEQ ID NO:29 [HuBa-1-3d heavy chain]

[0114] [ka] SEQ ID NO:30 [HuBa-1-3d light chain]

[0115] [ka] SEQ ID NO:37 [HuBa-1-3d heavy chain, terminal K]

[0116] [ka] KAAG1 SEQ ID NO:38 [3A4 VH]

[0117] [ka] SEQ ID NO:39 [3A4 VL]

[0118] [ka] SEQ ID NO: 40 [3A4 heavy chain]

[0119] [ka] SEQ ID NO: 41 [3A4 light chain]

[0120] [ka] SEQ ID NO:48 [3A4 heavy chain, terminal K]

[0121] [ka] SEQ ID NO: 49 [3A4-L2 VL]

[0122] [ka] SEQ ID NO:50 [3A4-L2 light chain]

[0123] [ka] SEQ ID NO:51 [3A4-K4 VL]

[0124] [ka] SEQ ID NO:52 [3A4-K4 light chain]

[0125] [ka] Certain aspects and embodiments of the present disclosure are described in more detail below with reference to the following examples, which are intended to be illustrative and not limiting. EXAMPLES

[0126] Planned clinical trial with ADCT-901 The potential of ADCT-901 in treating solid tumors has been tested in mouse xenograft models of human-derived triple-negative breast cancer (TNBC), ovarian cancer, and renal cancer, with significant tumor reduction observed in mice after receiving a single dose of ADCT 901. The efficacy of ADCT-901 in these models is attributed to the targeted delivery of the PBD dimeric cytotoxin SG3199. Kidney-associated antigen 1 (KAAG1) is an antigen recognized by cytolytic T lymphocytes. KAAG1 is an attractive novel tumor target for ADC development with high expression on tumor cell surface in tumors with high unmet medical need, including ovarian cancer, prostate cancer, and triple-negative breast cancer, but its expression on healthy tissues is very restricted. ADCT-901 will be investigated in ovarian / fallopian tube cancer, prostate cancer, triple-negative breast cancer, cholangiocarcinoma, and renal cell carcinoma.

[0127] research design The study is a Phase 1, multicenter, open-label study with a dose escalation portion followed by a dose expansion portion. The dose escalation portion of the study (Part 1) is designed to establish a safe and tolerated dose and dosing schedule of ADCT-901 for further testing in patients with selected advanced solid tumors. The dose and dosing schedule identified in Part 1 will be tested in the dose expansion portion of the study (Part 2) to further characterize safety and tolerability and evaluate preliminary efficacy in the study population. Part 1 will utilize a 3+3 dose escalation design. Part 2 will include patients who are likely to respond based on preliminary efficacy results from Part 1 and will further evaluate the safety and tolerability of the recommended dose / schedule. Part 2 is based on a flat dosing regimen. Chemotherapeutic agents have traditionally been administered with weight-based normalization to minimize potential toxicity. However, for protein therapeutics (including antibody-drug conjugates), the administration is not always optimal, as the agents usually have a low central distribution volume and are confined to the vascular space. Given that blood volume is less than proportional to body weight, weight-based dosing may result in overexposure for high-weight patients and less than optimal exposure for low-weight patients. Therefore, we chose a flat dosing paradigm for ADCT-901 to normalize exposure for patients at the extremes of body weight, even though this is not a commonly used dosing regimen for antibody drug conjugates.

[0128] In the dose escalation portion (Part 1), patients will receive escalating doses of ADCT-901 guided by a 3+3 design. In the dose expansion portion (Part 2), two arms of patients are planned to be treated at the expanded recommended dose (RDE). Group 1: Indications in which ADCT-901 has shown preliminary activity in Part 1. Group 2: A group of patients with the indications in Part 1, excluding those selected in Group 1 in Part 2. No more than 30% of patients with the same indications will be admitted to this basket group. The RDE is defined as a dose level below the maximum tolerated dose (MTD) and is determined by evaluation of the safety profile, antitumor activity, PK, and biomarker data (when available). Enrollment may be expanded at doses lower than the current dose level that are evaluated as part of the dose escalation process; additional patients with the same indication may only be added at a dose level equal to or higher than the dose level at which at least one patient with a documented partial response (PR) or complete response (CR) has been observed. No more than 10 patients in total may be treated at such a dose level, unless 3 or more of the 10 patients have documented a PR or CR.

[0129] Objectives and relevant endpoints

[0130] [Table 2] Patient population To be eligible for the study, patients must meet all inclusion criteria and not exclusion criteria. Unless otherwise specified, all criteria must be assessed during screening. Future approval of protocol deviations to recruitment and enrollment criteria, also known as protocol waivers or exemptions, will not be permitted.

[0131] Inclusion criteria 1. Written consent must be obtained prior to the procedure 2. Male or female patients aged 18 years or older 3. Pathological diagnosis of selected solid tumor malignancies that are locally advanced or metastatic at the time of screening: cholangiocarcinoma, ovarian / fallopian tube cancer, prostate cancer, renal cell carcinoma, and triple-negative breast cancer Note: Neuroendocrine features of the prostate and histologic variants of prostate cancer, including small cell carcinoma, are accepted. 4. Patients who, in the opinion of the investigator, are refractory or intolerant to existing therapy(s) known to provide clinical benefit to their condition. 5.Patients with measurable disease as determined by RECIST v1.1 6. For patients enrolled in the first two dose levels of Part 1: Must provide an archived formalin-fixed paraffin-embedded (FFPE) tumor tissue block. Any biopsy from initial diagnosis is acceptable, but if several specimens are available, the most recent specimen is preferred. 7. Eastern Cooperative Oncology Group (ECOG) performance status 0-2 8.Patients with a life expectancy of 3 months or more as assessed by the investigator 9. Adequate organ function as defined by screening laboratory values ​​within the following parameters: a) Absolute neutrophil count (ANC) ≥ 1.5 × 103 / μL (off growth factors for at least 72 hours [h]) b) No transfusion in the past 10 days and platelet count ≥ 100 × 103 / μL c) Hemoglobin ≥ 9 g / dL (5.6 mmol / L) (pre-transfusions allowed 7 days prior to C1D1) d) Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma glutamyltransferase (GGT) ≦2.5×upper limit of normal (ULN) in the absence of hepatic involvement; ALT and AST ≦5×ULN in the presence of hepatic involvement. e) Total bilirubin ≦1.5×ULN (patients with known Gilbert's syndrome may have total bilirubin up to ≦3×ULN and direct bilirubin ≦1.5×ULN). Calculate creatinine clearance ≥ 60 mL / min according to the Cockcroft-Gault formula. f) Women of childbearing potential (WOCBP) must agree to use highly effective contraception from the time they give informed consent until at least 9.5 months after the last dose of study drug. Men with female partners of childbearing potential must agree to use condoms when sexually active or practice total abstinence from the time they give informed consent until at least 6.5 months after the last dose of study drug.

[0132] Exclusion criteria 1. Participation in other investigational interventional studies. 2. Known history of grade 3 or greater hypersensitivity to therapeutic antibodies. 3. Patients who have had a previous solid organ transplant. 4. Human immunodeficiency virus (HIV) seropositivity. 5. Serological evidence of chronic Hepatitis B virus (HBV) infection and unable or unwilling to undergo standard preventive antiviral therapy or have a detectable HBV viral load. 6. Serological evidence of Hepatitis C virus (HCV) infection without completion of therapeutic treatment or with detectable HCV viral load. 7. History of recent infection requiring IV antibiotic, IV antiviral, or IV antifungal treatment within 4 weeks of C1D1 8. History of Stevens-Johnson syndrome or toxic epidermal necrolysis 9.Failure to resolve acute non-hematologic toxicity from previous treatment (≤ Grade 2 for neuropathy or alopecia) to ≤ Grade 1 (Common Terminology Criteria for Adverse Events version 5.0 [CTCAE v5.0]) prior to screening. 10. Evidence of symptomatic central nervous system (CNS) metastases or leptomeningeal disease (brain MRI or previously documented cerebrospinal fluid cytology). Previously treated asymptomatic CNS metastases are permitted if last treatment (systemic anticancer therapy and / or local radiotherapy) was completed 4 weeks or more prior to Day 1, except with low dose steroids in tapered doses (i.e., up to 10 mg prednisone or equivalent is permitted on Day 1 and consecutive days, if tapered). Patients with non-contiguous dural metastases are eligible. 11. Clinically significant third cavity fluid accumulation (i.e., ascites requiring drainage or any serosal effusion either requiring drainage or associated with shortness of breath). 12. Active diarrhea ≥ CTCAE grade 2 or medical condition associated with chronic diarrhea (e.g., irritable bowel syndrome, inflammatory bowel disease). 13. Active infection requiring systemic antibiotic treatment. 14. Active bleeding diathesis or therapeutic anticoagulation with oral vitamin K antagonist with target INR>2. 15. Breastfeeding or pregnant. 16. Significant medical comorbidities including uncontrolled hypertension (recurrent systolic blood pressure [BP] ≥ 160 mmHg and / or diastolic blood pressure ≥ 110 mmHg with or without the use of antihypertensive medications), unstable angina, congestive heart failure (New York Heart Association class II or higher), acute ischemia, coronary angioplasty or myocardial infarction confirmed by electrocardiogram within 6 months prior to screening, uncontrolled severe atrial or ventricular arrhythmias, active ulceration of the upper gastrointestinal (GI) tract or GI bleeding, or severe chronic pulmonary disease. 17. Active or clinically significant ocular disease, including ocular surface disease at baseline. Ocular evaluation will be confirmed by an ophthalmologist at screening. Patients with a previous episode of cicatricial conjunctivitis (as assessed by the investigator) will be ineligible. 18. Major surgery, radiation therapy, chemotherapy, or other antineoplastic therapy within 14 days (except for a shorter period if approved by the sponsor) prior to starting the investigational drug (C1D1). 19. Use of any other experimental medication within 14 days prior to starting the investigational product (C1D1). 20. Congenital long QT syndrome or corrected QTcF interval of ≥ 480 ms at screening (unless secondary to pacemaker or bundle branch block). 21. Active second primary malignancy other than non-melanoma skin cancer, non-metastatic prostate cancer, cervical carcinoma in situ, ductal carcinoma in situ or lobular carcinoma in situ of the breast, or any other malignancy documented by the Sponsor's medical monitor and investigator in agreement that should not be excluded. 22. Planned administration of a live vaccine within 30 days prior to and during the first dose of study treatment. 23. Any other significant medical disease, disorder, or condition that, in the opinion of the Investigator, renders the patient unsuitable for study participation or places the patient at risk.

[0133] Sample size Approximately 76 patients. Part 1 - approximately 46 patients. Part 2 - approximately 30 patients (divided equally between arms 1 and 2).

[0134] Estimated duration of patient participation and study duration The duration of study participation for each patient is defined as the time from the date of signed written informed consent to completion of follow-up, withdrawal of consent, loss to follow-up, or death, whichever occurs first. The study includes a screening period (up to 21 days), a treatment period (with 3-week cycles of the every 3 weeks [Q3W] dosing regimen), and a follow-up period (approximately every 9 weeks) for up to 1 year after the end-of-treatment visit (EOT). Patients may continue on study treatment until disease progression, AE, or other discontinuation criteria, whichever occurs first. The overall completion of the trial will occur at the last patient's last visit or last scheduled procedure, unless the trial is terminated earlier by the sponsor.

[0135] Study drug, dose, and mode of administration ADCT-901 is an antibody-drug conjugate (ADC) composed of a humanized monoclonal antibody (3A4) against human kidney-associated antigen 1 (KAAG1) conjugated via a cathepsin-cleavable linker to SG3199, a pyrrolobenzodiazepine (PBD) dimeric cytotoxin. The PBD dimeric cytotoxin (SG3199) bound to the linker is designated tesirin / SG3249. ADCT-901 is administered as an intravenous (IV) infusion over 30 minutes. Patients treated with ADCT-901 monotherapy will receive 15 μg / kg Q3W in the initial dose cohort, with the highest dose that may be tested being 290 μg / kg or 22 mg Q3W. The dose escalation portion of the study will begin with the use of weight-based dosing and, upon approval, transition to flat dosing at a flat dose equivalent to the highest weight-based dose level tested and deemed safe. Transitions to lower flat dose levels may occur. If two dose-limiting toxicities (DLTs) are observed at the first flat dose level investigated, the next lower flat dose level may be investigated. Dose expansion will occur at the doses identified as the RDE / MTD. Dose escalation of ADCT-901 follows a modified Fibonacci sequence. Table 1 - Dose levels in dose escalation (Part 1)

[0136] [Table 3] Q3W=Every 3 weeks *Additional or intermediate dose levels or different dosing schedules may be implemented during the study, but doses will not be higher than 290 μg / kg Q3W or 22 mg Q3W, or equivalent (e.g., 96.7 μg / kg or 7.3 mg weekly).

[0137] Premedication Unless contraindicated, dexamethasone 4 mg orally (PO) or its equivalent is given twice daily according to the following schedule: The day before each ADCT-901 dose (if possible). Day of ADCT-901 administration (first dose at least 2 hours prior to dosing if not given the previous day; otherwise, any time prior to dosing). The day after administration of ADCT-901. Dexamethasone or its equivalent can be given IV to patients who cannot take it PO (IV dexamethasone can be given 30 minutes prior to ADCT-901 if given on the day of dosing). Dose modification Doses are modified as necessary to manage any specific toxicities.

[0138] Research evaluation Safety assessment Safety will be assessed based on physical examination, ECOG performance, height and weight, vital signs; clinical laboratory tests (hematology, chemistry, coagulation, and urinalysis); and ophthalmological examination. All safety assessments on dosing days will be performed prior to administration of study drug unless otherwise specified. Further safety assessments may be performed by the investigator if clinically indicated. Pharmacokinetic and immunogenicity assessment. Pharmacokinetics The PK profiles of ADCT-901 PBD-conjugated antibody, whole antibody, and unconjugated warhead SG3199 will be evaluated in serum by a central laboratory designated by the sponsor using validated bioanalytical methods. To understand the metabolic processing of ADCT-901 in humans, samples remaining after PK analysis is completed may be pooled across patients for potential metabolite identification. The PK profile includes determination of maximum concentration (Cmax), time to Cmax (Tmax), area under the concentration-time curve from time zero to the last quantifiable concentration (AUClast), area under the concentration-time curve from time zero to the end of the dosing interval (AUCtau), area under the concentration-time curve from time zero to infinity (AUCinf), apparent terminal elimination half-life (Thalf), apparent clearance (CL), apparent volume of distribution (Vss), and accumulation index (AI). PK parameters are determined for all PK-evaluable patients using non-compartmental population PK analysis using Phoenix WinNonlin (Certara US, Inc., Princeton, NJ, US) or other appropriate software. Ancillary population PK analysis can be performed to evaluate population PK parameters for typical patients and to identify covariate factors that affect drug disposition and reported separately. Potential correlations of PK parameters to baseline characteristics and safety observations can be evaluated and reported separately. Additionally, the impact of ADCT-901 PBD. Conjugated antibody and unconjugated warhead SG3199 concentrations on QTc interval can be evaluated and reported separately. immunogenicity Detection of anti-drug antibodies (ADA) is performed by using screening assays, confirmatory assays, and titer assessments for identification of antibody positive samples / patients. Efficacy evaluation Disease assessments will be performed 6 and 12 weeks after C1D1, and then every 9 weeks until disease progression or initiation of new anticancer therapy; if a patient discontinues study drug due to clinical progression, disease assessments are required at EOT. Screening (baseline) imaging must occur within 4 weeks prior to C1D1. During the treatment period, imaging will be performed 6 weeks (42 days ± 7 days) after C1D1 but before C3D1, and 12 weeks (84 days ± 7 days) after C1D1 but before C5D1, then every 9 weeks (63 days ± 14 days) until EOT. Disease assessments should be performed at the specified time points, even if dosing of study drug is delayed. During the follow-up period, patients who discontinue study drug for reasons other than disease progression or initiation of other anticancer therapy will have imaging performed every 9 weeks (63 days ± 14 days) until disease progression, initiation of other anticancer therapy, one year after EOT. Further disease assessments may be obtained if clinically indicated. Disease assessments will be performed by CT or MRI scans with contrast, or by other validated imaging methods (i.e., PET-CT, bone scan, x-ray) of the chest, abdominal and pelvic regions, and other body regions, if applicable, if clinically indicated. A brain scan (CT or MRI with contrast) will be performed, if applicable. Efficacy analyses will be based on investigator-determined response according to RECIST v1.1. Overall response rate Overall response rate (ORR) is defined as the proportion of patients with a best overall response (BOR) of CR or PR. Overall response categories are derived based on response assessments performed at or before the initiation of subsequent anticancer therapy. Percentages of ORR and their 95% CI are presented. BOR for stable disease (SD), as opposed to CR, PR, or PD, can only be performed after patients have been on study for a minimum of 35 days after the first dose of study drug. Any tumor evaluation showing SD before this period is considered unevaluable for BOR if no evaluation after this period is available. Response duration Duration of response (DOR) is defined among responders (CR or PR) as the time from the earliest date of first response to the first date of either disease progression or death from any cause. For patients who have not progressed or died at the time of analysis, censoring is performed using the date of the last valid disease assessment before the start of a new anticancer therapy. Data are analyzed by Kaplan-Meier method. Median DOR and 95% CI are presented. DOR is analyzed by response subgroups (CR, PR). Progression-free survival Progression-free survival (PFS) is defined among all treated patients as the time from the first dose of study drug to the first date of either disease progression or death from any cause. Patients who have not progressed or died at the time of analysis are censored using the date of the last available disease assessment before the start of a new anticancer therapy. Data are analyzed by the Kaplan-Meier method. Median PFS times and 95% CI are presented. overall survival Overall survival (OS) is defined as the time from first administration of study drug to death from any cause. For patients who were not dead at the time of analysis, censoring was performed using the date the patient was last known to be alive. Data were analyzed by the Kaplan-Meier method. Median OS and 95% CI are presented. EXAMPLES

[0139] Example 2: Planned Clinical Trials with ADCT-601 clinical background The receptor tyrosine kinase AXL belongs to the TAM (TYRO-3, AXL, and MER) family and is characterized by an extracellular domain, a single transmembrane domain, and an intracellular protein tyrosine kinase domain. In normal tissues, AXL expression has been reported in a wide range of organs, such as smooth muscle, bone marrow stromal and bone marrow cells, brain, heart, skeletal muscle, testis, endothelial cells, and liver. Importantly, AXL expression in normal tissues is significantly lower when compared to tumors. Several studies have highlighted the role of AXL activation and AXL expression in tumor progression, metastasis development, especially through epithelial-mesenchymal transition (EMT), and poor prognosis. Several studies have suggested that AXL expression is induced by both targeted and chemotherapeutic drugs, and that drug-induced AXL expression confers resistance to both conventional chemotherapy and targeted therapy. AXL is highly overexpressed or ectopically expressed in a number of solid tumors (e.g., sarcoma and pancreas). AXL gene amplification is observed in several types of tumors, albeit at a low frequency. Based on the predominance of AXL-expressing cells in solid malignant tumors and the relationship between increased AXL expression, poor prognosis, and resistance to chemotherapy, AXL is considered a potential target for the treatment of patients with advanced solid tumors. Sarcomas are a rare and heterogeneous group of malignant tumors of mesenchymal origin that comprise less than 1% of all adult malignancies and 20% of childhood cancers. Current treatment options for patients with sarcomas vary with clinical stage but may include surgery, radiation therapy, and chemotherapy. Despite available chemotherapy, approximately 50% of patients with soft tissue sarcomas will develop recurrent / metastatic disease, yet the prognosis for metastatic and refractory sarcomas remains dismal: median survival is only 12-18 months. Active agents and newer regimens with significant activity in sarcomas have not been developed and there remains a medical need.

[0140] AXL Status Our previous study, ADCT-601-101, enrolled an unselected patient population. A more selected population of AXL-expressing patients will help further evaluate the safety and preliminary activity of ADCT-601 as a monotherapy. The most common alterations of the AXL gene in patients with solid tumors are AXL mutations (1.69%), AXL amplification (0.21%), AXL H292fs (0.09%), AXL loss (0.09%), and AXL fusion (0.04%). In samples of several tumor types, it was observed that the presenting AXL amplification had a higher median AXL mRNA expression than samples with diploid AXL status, suggesting high AXL expression. This was observed in several tumor entities: sarcoma, ovarian serous cystadenocarcinoma, pancreatic adenocarcinoma, cervical squamous cell carcinoma, uterine endometrial carcinoma, and bladder carcinoma. These data suggest that in a larger group of patients with AXL-overexpressing tumors, there may be a small subset of AXL tumors overexpressing AXL driven by AXL amplification. This subgroup, although small, may constitute an enriched AXL-overexpressing population that could benefit from AXL-targeted therapy. Based on the inventors' ability to use AXL gene amplification to enrich the population of selected tumors to be investigated, as well as the premise that the patients may overexpress AXL, investigation of ADCT-601 monotherapy is appropriate in selected indications (sarcoma, ovarian / fallopian tube / primary peritoneal cancer, pancreatic cancer, bladder cancer, cervical cancer, or endometrial cancer).

[0141] Combination with gemcitabine Gemcitabine is a nucleoside metabolic inhibitor. It inhibits DNA synthesis by inhibiting cell cycle specific ribonucleotide reductase in S phase (and blocks cell progression in G1 / S phase). It has been used as a monotherapy or combination chemotherapy to treat various cancers. Our internal data shows the antitumor activity of ADCT-601 in combination with gemcitabine. ADCT-601 and gemcitabine were tested alone or in combination in pancreatic cancer PAXF 1657 patient-derived xenograft model. ADCT-601 produced dose-proportional antitumor activity when tested as a single agent, which was also reflected by a proportionally significant increase in survival rate. Treatment with gemcitabine alone produced limited antitumor activity. Combination of ADCT-601 with gemcitabine produced potent and sustained antitumor activity.

[0142] research design This is a Phase 1b multicenter open-label study with dose escalation and dose expansion portions. Approximately 66 patients will be enrolled. As in Example 1, we chose a flat dosing paradigm for ADCT-601 to normalize exposure for patients at the extremes of body weight, even though this is not a commonly used dosing regimen for antibody-drug conjugates. In the dose escalation part (Part 1), the two arms will be run independently and in parallel with each other. Arm A: Patients with selected indications of sarcoma will receive gemcitabine in combination with ADCT-601. Arm B: Patients with AXL gene amplification and selected indications will receive ADCT-601 monotherapy. Patients in Arm A and Arm B will receive escalating doses of ADCT-601 guided by a 3+3 design (fixed dose of gemcitabine when combined in Arm A). In the dose expansion portion (Part 2), the two arms will be run independently and in parallel with each other. Arm A: Patients with selected symptomatic sarcomas will receive ADCT-601 in combination with gemcitabine Group 1: Patients who have not received gemcitabine in a previous line of treatment (N=approximately 15 patients) Group 2: Patients who received a gemcitabine-containing regimen in a previous line of treatment (N=approximately 6 patients) Arm B: Patients with AXL gene amplification and selected indications will receive ADCT-601 monotherapy. (N=approximately 15 patients) The AXL gene amplification status of patients enrolled in Arm B will be obtained from local next-generation sequencing (NGS) tests or local single nucleotide polymorphism (SNP) array tests, or comparative genomic hybridization (CGH) tests used in clinical practice for the assessment of genetic alterations in cancer patients.

[0143] assignment The primary objectives are to characterize the safety and tolerability of mipasetamab uzoptirine as monotherapy and in combination with gemcitabine, and to identify recommended doses and schedules for future studies in patients with advanced / metastatic solid tumors. Secondary objectives include evaluating the preliminary antitumor activity of ADCT-601 monotherapy and in combination with gemcitabine. Patient population To be eligible for the study, patients must meet all inclusion criteria and not exclusion criteria. Unless otherwise specified, all criteria must be assessed during screening. Future approval of protocol deviations to recruitment and enrollment criteria, also known as protocol waivers or exemptions, will not be permitted. Inclusion criteria The same procedure as in Example 1 was carried out with the following changes: 2. Male or female patients aged 18 years or older. -US only: For sarcoma patients in Groups A and B: ≥ 16 years of age 3. Pathologic diagnosis of locally advanced or metastatic solid tumor malignancy at screening: Arm A: Sarcoma indications selected from two separate categories: -Soft tissue sarcomas: leiomyosarcoma, liposarcoma, undifferentiated pleomorphic sarcoma (UPS) and synovial sarcoma -Osteosarcoma: Ewing's sarcoma, osteosarcoma and chondrosarcoma b. Arm B: Patients with sarcoma (any indication of sarcoma except those listed in Arm A), ovarian / fallopian tube / primary peritoneal, pancreatic, bladder, cervical, or endometrial cancer with known AXL gene amplification status.4. Patients who are refractory or intolerant to available standard therapies. provide clinical benefit for their condition, according to the investigator's judgment. Dose Expansion (Part 2), Arm A: · Group 1: Patients must be gemcitabine naïve. · Arm 2: Patients must have previously received a gemcitabine-containing regimen. Exclusion criteria As in Example 1, the following additional criteria were used: Previous treatment with compounds that target AXL as their primary mechanism of action.

[0144] Study drug, dose, and mode of administration ADCT-601 (mipasetamab uzoptirine) is an antibody-drug conjugate (ADC) composed of a humanized IgG1 (1H12-HAKB) against human AXL, site-specifically conjugated to PL1601 using GlycoConnect™ technology, and contains a HydraSpace™, cleavable linker and the pyrrolobenzodiazepine (PBD) dimeric cytotoxin SG3199. In arm A, patients will be treated with ADCT-601 in combination with gemcitabine for six cycles, followed by ADCT-601 monotherapy. In arm B, patients will be treated with ADCT-601 monotherapy. ADCT-601 will be administered as an intravenous (IV) infusion over 30 minutes on Day 1 of each cycle every three weeks (Q3W). Gemcitabine will be administered as an IV infusion over 30 minutes Q3W on days 1 and 8 of each cycle for 6 cycles. Table 2 - ADCT-601 Dose Levels

[0145] [Table 4] *Additional or intermediate dose levels or different dosing schedules may be implemented during the study, but doses will not be higher than 11 mg for ADCT-601 in combination with gemcitabine and 23 mg for ADCT-601 monotherapy.

[0146] Patients should maintain the same treatment schedule throughout the duration of the study. However, if an RDE is identified, patients receiving lower or higher dose levels of ADCT-601 enrolled in Part 1 may be offered continued treatment with the RDE. For example, additional lower and / or intermediate dose levels or different dosing schedules can be implemented relative to the interim dose levels to manage any particular toxicities.

[0147] Premedication Unless contraindicated, dexamethasone 4 mg orally (PO) or its equivalent (eg, prednisone 25 mg) is administered twice daily according to the following schedule: The day before each ADCT-601 dose (if possible). Day of ADCT-601 administration (first dose at least 2 hours prior to dosing if not given the previous day; otherwise, any time prior to dosing). The day after administration of ADCT-601. Dexamethasone or its equivalent can be given IV to patients who cannot take it PO (IV dexamethasone can be given 30 minutes prior to ADCT-601 if given on the day of dosing).

[0148] Research evaluation These are carried out in the same manner as in the first embodiment. ******* Certain publications are cited above to more fully describe and disclose the disclosure and the state of the art to which the invention herein may pertain. Each of the references mentioned in this disclosure is incorporated herein by reference in its entirety.

Claims

1. 1. A method of treating a proliferative disorder in a subject, comprising administering to the subject an antibody-drug conjugate (ADC), wherein the drug is a pyrrolobenzodiazepine (PBD) dimer, and the ADC is administered to the subject using a flat dosing regimen for one or more cycles.

2. 2. The method of claim 1, wherein the dose of the ADC administered per cycle is 2-20 mg.

3. 2. The method of claim 1, wherein the dose of the ADC administered per cycle is 2-5 mg, 6-10 mg, 11-15 mg, or 16-20 mg.

4. 2. The method of claim 1, wherein the dose of the ADC administered per cycle is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 mg.

5. The method of claim 1 or 2, wherein the antibody specifically binds to a tumor antigen.

6. The method of claim 3, wherein the tumor antigen is CD19, CD22, CD25, AXL, DLK-1 or KAAG1.

7. The PBD dimer has the following formula I: 【Chemistry 1】 (In the formula, (a) R ＬＬ is a linker for linking to the Ab; (b)(i)R １０ and R １１ (ii) R １０ R is a linker for connection to Ab ＬＬＡ and R １１ is OH, where R ＬＬ and R ＬＬＡ may be the same or different; or (iii) R １０ is a capping group RC, R １１ is OH; (c) m is 0 or 1; (d) When a double bond is present between C2 and C3, R ２ is methyl; When a single bond is present between C2 and C3, R ２ is H or 【Chemistry 2】 and When a double bond is present between C2' and C3', R １２ is methyl; When a single bond is present between C2' and C3', R １２ is H or 【Chemistry 3】 (It is) The method according to any one of claims 1 to 6, wherein

8. The PBD dimer has the following formula (III): 【Chemistry 4】 (In the formula, (a) R ＬＬ is a linker for linking to the Ab; (b)(i)R １０ and R １１ (ii) R １０ is a linker for linking to Ab, R ＬＬＡ and R １１ is OH; or (iii) R １０ is a capping group RC, R １１ is OH; and (c) m is 0 or 1. The method according to any one of claims 1 to 7, wherein

9. R ＬＬ is represented by the following formula (Ia): 【Chemistry 5】 (In the formula, The questions are as follows: 【Chemistry 6】 wherein QX is such that Q is an amino acid residue, a dipeptide residue, a tripeptide residue or a tetrapeptide residue; X is one of the following: 【Chemistry 7】 (wherein a=0 to 5, b1=0 to 16, b2=0 to 16, c1=0 or 1, c2=0 or 1, d=0 to 5, at least b1 or b2=0, and at least c1 or c2=0); G ＬＬ is a linker group attached to the antibody The method according to claim 7 or 8, wherein

10. The method of any one of claims 7 to 9, wherein the linker comprises a cleavable linker, including a linker comprising a cathepsin cleavable sequence, Val-Ala or Val-Cit.

11. The method of any one of claims 1 to 10, wherein the PBD dimer is conjugated to the antibody at an endogenous and / or engineered N-linked glycosylation site.

12. The method of any one of claims 1 to 11, wherein dosing is Q3W.

13. The method of any one of claims 1 to 12, wherein the flat dosing is 2 or more cycles.

14. The method of any one of claims 1 to 13, wherein all doses are administered to the patient as a flat dosing regimen.

15. 15. The method of any one of claims 1 to 14, wherein the ADC is selected from ADCT-301, ADCT-402, ADCT-601, ADCT-602, ADCT-701, or ADCT-901.

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