Dose Escalation Study to Investigate the Safety, Pharmacokinetics, Pharmacodynamics, Immunogenicity and Clinical Activity of GSK2857916

A Phase I Open-label, Dose Escalation Study to Investigate the Safety, Pharmacokinetics, Pharmacodynamics, Immunogenicity and Clinical Activity of the Antibody Drug Conjugate GSK2857916 in Subjects With Relapsed/Refractory Multiple Myeloma and Other Advanced Hematologic Malignancies Expressing BCMA

This study will assess the safety, pharmacokinetic (PK), pharmacodynamic (PD) and the therapeutic potential of GSK2857916 in subjects with multiple myeloma (MM) and lymphomas that express B cell maturation antigen (BCMA). The hypothesis is that GSK2857916 can be safely administered to subjects with MM and with BCMA positive malignancies at doses where target engagement can be demonstrated. This study will determine if adequate target engagement of BCMA receptors translates into clinical benefit for subjects with MM and BCMA positive lymphomas. The study will consists of two parts: a Part 1 dose escalation phase and a Part 2 expansion phase for safety, tolerability, PK, PD, and clinical activity testing. The study will enroll a total of approximately 80-95 subjects with relapsed/refractory MM or BCMA-expressing hematologic malignancies. The maximum dose to be administered in this trial will not exceed 5 milligram/kilogram(mg/kg).

Inclusion Criteria:

• Provide signed written informed consent, which includes compliance with the requirements and restrictions listed in the consent form.
• Male or female, 18 years or older (at the time consent is obtained)
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• Part 1/dose escalation; Histologically or cytologically confirmed diagnosis of Multiple Myeloma in a subject who fulfills all of the following: has undergone stem cell transplant, or is considered transplant ineligible, has been pretreated with at least the 3 following classes of anti-myeloma drugs: alkylators, proteasome inhibitors and immunomodulators, has demonstrated progression on, or within 60 days of completion of the last therapy.

Part 2 /MM cohort; Histologically or cytologically confirmed diagnosis of: Multiple Myeloma in a subject who fulfills all of the following: has undergone stem cell transplant, or is considered transplant ineligible, has been pretreated with at least the 3 following classes of anti-myeloma drugs: alkylators, proteasome inhibitors and immunomodulators, has demonstrated progression on, or within 60 days of completion of the last therapy, and has measurable disease with at least one of the following: serum M-protein >=0.5 gram (g)/decilitre (dL) (>=5 g/Litre (L)), urine M-protein >=200 milligram (mg)/24hour (h).

Serum free light chain (FLC) assay: Involved FLC level >=5 mg/dL (>=50 mg/L) and an abnormal serum FLC ratio (<0.26 or >1.65) and biopsy proven plasmacytoma (should be measured within 28 days of Screening Visit).

• Part 2/Other BCMA positive Hematologic Malignancies cohort: Subject with one of the following lymphomas: Diffuse Large B-cell Lymphoma (DLBCL) or follicular lymphoma (FL) that exhibits positive BCMA expression on tumor cells as determined by a central laboratory using a validated Immunohistochemistry (IHC) assay. Eligible subjects with BCMA positive malignancies must also fulfill the prior treatment requirements as follows: DLBCL: at least 2 prior lines of systemic therapy containing at least one line of chemo-immunotherapy with anti-CD20 antibody, and either has undergone stem cell transplant or is considered transplant ineligible. FL: at least 2 prior lines of systemic therapy.
• Subjects with a history of autologous stem cell transplant are eligible for study participation provided the following eligibility criteria are met: transplant was > 100 days prior to study enrolment, no active infection; subject meets the remainder of the eligibility criteria outlined in the study protocol.
• Adequate organ system functions as defined below Absolute neutrophil count>=1.0x10^9/L, hemoglobin>=8.0 g/dL, platelet>=50x10^9/L, international normalized ration (INR) <=1.5, Partial thromboplastin time <=1.5xupper limit of normal (ULN), total bilirubin <=1.25xULN, alanine aminotransferase and aspartate aminotransferase<=1.5 X ULN, serum creatinine or calculated creatinine clearance<1.2XULN >=60 mL/min for Part 1;>=50 mL/minute (min) for Part 2 if data supports loosening criteria, Albuminuria<=500 mg/24h, left ventricular ejection fraction >=50%, Troponin<=1xULN, Calcium<=1.1xULN
• A female subject is eligible to participate if she is of: Non-childbearing potential or women of childbearing potential must have a negative serum pregnancy test within 72 hours of first dose of study treatment and agree to use effective contraception during the study and for 60 days following the last dose of study treatment.
• Men with a female partner of childbearing potential must have either had a prior vasectomy or agree to use effective contraception from the time of first dose of study until 60 days after the last dose of study treatment to allow for clearance of any altered sperm
• All prior treatment-related toxicities (defined by National Cancer Institute- Common Toxicity Criteria for Adverse Events, version 4) must be <=Grade 1 at the time of enrollment except for alopecia, and grade 2 neuropathy.

Exclusion Criteria:

• Systemic anti-tumor therapy within 14 days, or plasmapheresis within 7 days prior to the first dose of study drug
• Use of an investigational drug within 14 days or five half-lives, whichever is shorter, preceding the first dose of study drug. Prior treatment with a monoclonal antibody within 30 days of receiving the first dose of study drug.
• History of an allogeneic stem cell transplant. Subjects with a history of an autologous stem cell transplant are NOT excluded if they meet inclusion criteria related to history of autologous stem cell transplant.
• Presence of active renal condition (infection, requirement for dialysis or any other condition that could affect subject's safety). Subjects with isolated proteinuria resulting from MM are eligible, provided they fulfil the inclusion criteria related to organ system function.
• Evidence of active mucosal or internal bleeding
• Any major surgery within the last four weeks.
• Any serious and/or unstable pre-existing medical, psychiatric disorder, or other conditions (including lab abnormalities) that could interfere with subject's safety, obtaining informed consent or compliance to the study procedures.
• Known active infection requiring antibiotic treatment
• Evidence of severe or uncontrolled systemic diseases (e.g., unstable or uncompensated respiratory, hepatic, renal or cardiac disease
• Subjects with previous or concurrent malignancies are allowed only if the second tumor is not contributing to the subject's illness. The subject must not be receiving active therapy, other than hormonal therapy for this disease and the disease must be considered medically stable for at least 2 years.
• Evidence of cardiovascular risk including any of the following: QT interval corrected>=470 millisecond, evidence of current clinically significant uncontrolled arrhythmias, history of myocardial infarction, acute coronary syndromes (including unstable angina), coronary angioplasty, or stenting or bypass grafting within six months of Screening, Class III or IV heart failure as defined by the New York Heart Association functional classification system, uncontrolled hypertension, subjects with intra-cardiac defibrillators or permanent pacemakers, abnormal cardiac valve morphology (>=grade 2) documented by echocardiogram (subjects with grade 1 abnormalities [i.e., mild regurgitation/stenosis] can be entered on study). Subjects with moderate valvular thickening should not be entered on study.
• Known immediate or delayed hypersensitivity reaction or idiosyncrasy to drugs chemically related to GSK2857916 or any of the components of the study treatment.
• Pregnant or lactating female.
• Known human immuno virus infection.
• Subjects with positive test for Hepatitis B surface (HBS-Ag) or Hepatitis B core (HBc)antigen
• Subjects with positive test for hepatitis C (HCV) infection are excluded regardless of viral load. If hepatitis C antibody test is positive, a confirmatory polymerase chain reaction (PCR) or Recombinant immunoblot assay (RIBA) test should be performed. If the PCR or RIBA test is negative, subject is eligible for this trial
• Current active liver or biliary disease (with the exception of Gilbert's syndrome or asymptomatic gallstones, liver metastases or otherwise stable chronic liver disease per investigator's assessment).
• Current corneal disease or a history of corneal disease.