Dose Escalation Study of Talquetamab in Participants With Relapsed or Refractory Multiple Myeloma (MonumenTAL-1)

A Phase 1, First-in-Human, Open-Label, Dose Escalation Study of Talquetamab, a Humanized GPRC5D x CD3 Bispecific Antibody, in Subjects With Relapsed or Refractory Multiple Myeloma

The purpose of this study is to characterize the safety of Talquetamab and to determine the recommended Phase 2 dose(s) (RP2Ds) and dosing schedule assessed to be safe for Talquetamab (Part 1 [Dose Escalation]) and to further characterize the safety of Talquetamab at the recommended Phase 2 dose(s) (RP2Ds) (Part 2 [Dose Expansion]).

The study will be conducted in 2 parts: dose escalation and dose expansion. The study will evaluate safety, tolerability, pharmacokinetics and preliminary antitumor activity of Talquetamab administered to adult participants with relapsed or refractory multiple myeloma. The overall safety of the study drug will be assessed by physical examinations, Eastern Cooperative Oncology Group performance status, laboratory tests, vital signs, electrocardiograms, adverse event monitoring, and concomitant medication usage. Disease evaluations will include peripheral blood and bone marrow assessments at screening (performed within 28 days) and to confirm stringent complete response (sCR), complete response (CR), or relapse from CR. The end of study (study completion) is defined as the last study assessment for the last participant in the study. Study record NCT04634552 is Phase 2 part of this study and study record NCT03399799 is Phase 1 part of this study.

Participants will receive IV infusion of Talquetamab at minimum anticipated biologic effect level (MABEL)-based starting dose until the completion of the end of treatment visit. Subsequent dose levels will be selected based on the review of all available data including, but not limited to, pharmacokinetic, pharmacodynamic, safety, and preliminary antitumor activity data.

Participants will receive Talquetamab SC. The dose levels will be selected to identify safe and tolerable putative RP2D(s).

Participants will receive IV infusion or SC injection of Talquetamab at each putative recommended Phase 2 dose(s) (RP2D[s]) as determined in Part 1.

The Dose Limiting Toxicities (DLTs) are based on drug related adverse events and defined as any of the following events: hematological / non-hematological toxicity of Grade 3 or higher.

Part 1 and Part 2: Number of Participants with Adverse Events (AEs) as a Measure of Safety and Tolerability

An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study.

From signing of Informed Consent Form (ICF) up to follow up (until 100 days after the last dose of study drug or until the start of subsequent anticancer therapy, if earlier [approximately 2.10 years])

Serum cytokine concentrations will be measured pre- and post-infusion of Talquetamab for biomarker assessment.

ORR is defined as the proportion of participants who have a partial response (PR) or better according to the international myeloma working group (IMWG) criteria.

CBR is defined as the proportion of participants who have a minimal response (MR) or better according to the IMWG criteria.

DOR is defined as time from date of initial documentation of a response (PR or better) to date of first documented evidence of PD, per IMWG criteria.

From the date of initial documentation of a response to the date of first documented evidence of progressive disease (PD) (approximately 2.10 years)

TTR is defined as the time between date of first dose of study drug and the first efficacy evaluation that the participant has met all criteria for PR or better.

From the date of first dose of study drug to the date of initial documentation of a response (approximately 2.10 years)

PFS is defined as time from date of first dose of study drug to date of first documented PD, per IMWG criteria, or death due to any cause, whichever occurs first.

Every 16 weeks until end of study, participant dies, withdrawn consent, or lost to follow up (up to 18 months)

Inclusion Criteria: Documented initial diagnosis of multiple myeloma according to International Myeloma Working Group (IMWG) diagnostic criteria Part 1: Participants with measurable multiple myeloma who have progressed on, or could not tolerate, all available established therapies. Part 2: Participants with multiple myeloma measurable by central laboratory assessment who have progressed on, or could not tolerate, all available established therapies; Serum monoclonal paraprotein (M-protein) level greater than or equal to (>=) 1.0 gram per deciliter (g/dL) or urine M-protein level >=200 milligram per 24 hours (mg/24 h) or light chain multiple myeloma without measurable disease in the serum or the urine: serum immunoglobulin free light chain (FLC) >= 10 mg/dL and abnormal serum immunoglobulin kappa lambda FLC ratio; If central laboratory assessments are not available, relevant local laboratory measurements must exceed the minimum required level by at least 25% Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1 Women of childbearing potential must have a negative pregnancy test at screening and prior to the first dose of study drug using a highly sensitive pregnancy test either serum (Beta human chorionic gonadotropin [beta-hCG]) or urine Sign an informed consent form (ICF) indicating that he or she understands the purpose of and procedures required for the study, and is willing to and able participate in the study. Consent is to be obtained prior to the initiation of any study-related tests or procedures that are not part of standard-of-care for the participant's disease Exclusion Criteria: Participants who received or plan to receive any live, attenuated vaccine within 4 weeks prior to the first dose, during treatment, or within 4 weeks of the last dose of Talquetamab. Non-live or non-replicating vaccines approved or authorized for emergency use (example, coronavirus disease [COVID]-19) by local health authorities are allowed Toxicities from previous anticancer therapies should have resolved to baseline levels or to Grade 1 or less except for alopecia or peripheral neuropathy Received a cumulative dose of corticosteroids equivalent to greater than or equal to ( >=) 140 milligram (mg) of prednisone within the 14-day period before the first dose of study drug (does not include pretreatment medication) An allogenic stem cell transplant within 6 months before first dose of study drug. Participants who received an allogeneic transplant must be off all immunosuppressive medications for 6 weeks without signs of graft-versus-host disease (GVHD); and/or an autologous stem cell transplant less than or equal to (<=) 12 weeks before first dose of study drug Documented history of central nervous system (CNS) involvement or exhibits clinical signs of meningeal involvement of multiple myeloma. If either is suspected, whole body magnetic resonance imaging (MRI) and lumbar cytology are required

Pillarisetti K, Edavettal S, Mendonca M, Li Y, Tornetta M, Babich A, Majewski N, Husovsky M, Reeves D, Walsh E, Chin D, Luistro L, Joseph J, Chu G, Packman K, Shetty S, Elsayed Y, Attar R, Gaudet F. A T-cell-redirecting bispecific G-protein-coupled receptor class 5 member D x CD3 antibody to treat multiple myeloma. Blood. 2020 Apr 9;135(15):1232-1243. doi: 10.1182/blood.2019003342.