A Study of Talquetamab and Teclistamab Each in Combination With a Programmed Cell Death Receptor-1 (PD-1) Inhibitor for the Treatment of Participants With Relapsed or Refractory Multiple Myeloma

A Phase 1b Study of Bispecific T Cell Redirection Antibodies in Combination With Checkpoint Inhibition for the Treatment of Participants With Relapsed or Refractory Multiple Myeloma

The purpose of the study is to identify the safe dose(s) of a PD-1 inhibitor in combination with talquetamab or teclistamab, and to characterize the safety and tolerability of talquetamab or teclistamab when administered in combination with a PD-1 inhibitor.

Inclusion Criteria:

• Have documented initial diagnosis of multiple myeloma according to International Myeloma Working Group (IMWG) diagnostic criteria
• Participants with relapsed or refractory disease that are not a candidate for available therapy with established clinical benefit
• Have measurable disease at screening as defined by at least 1 of the following: a) Serum M-protein level greater than or equal to (>=) 0.5 grams per deciliter (g/dL); b) Urine M-protein level >= 200 milligrams (mg) per 24 hours; c) Light chain multiple myeloma: Serum immunoglobulin (Ig) free light chain (FLC) >= 10 milligrams/deciliter (mg/dL) and abnormal serum Ig kappa lambda FLC ratio
• Have an Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1

Exclusion Criteria:

• Prior antitumor therapy within 21 days prior to the first dose of study treatment (proteasome inhibitor [PI] therapy or radiotherapy within 14 days, immunomodulatory drug (IMiD) agent therapy within 7 days, gene -modified adoptive cell therapy or autologous stem cell transplant within 3 months)
• Prior therapy with PD-1 inhibitors, allogeneic stem cell transplant or solid organ transplant
• Active plasma cell leukemia, Waldenstrom's macroglobulinemia, POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes), or primary light chain amyloidosis
• Active Central Nervous System (CNS) involvement or exhibition of clinical signs of meningeal involvement of multiple myeloma. If either is suspected, brain magnetic resonance imaging (MRI) and lumbar cytology are required
• Live, attenuated vaccine within 4 weeks before the first dose of study treatment
• Non-hematologic toxicity from prior anticancer therapy that has not resolved to baseline levels or to Grade less than or equal to (<=) 1 (except alopecia [any grade] or peripheral neuropathy to Grade <= 2)
• Received a cumulative dose of corticosteroids equivalent to >= 140 milligrams (mg) of prednisone within the 14-day period before the start of study treatment administration