A Study of Teclistamab in Japanese Participants With Relapsed or Refractory Multiple Myeloma

The purpose of the study is to evaluate the safety and tolerability in Japanese participants with relapsed or refractory multiple myeloma (RRMM) at the recommended Phase 2 dose (RP2D) identified in Study 64007957MMY1001 (NCT03145181) in Phase 1 part and to evaluate the efficacy of teclistamab at RP2D for Japanese participants in Phase 2 part.

Inclusion criteria: * Documented diagnosis of multiple myeloma (MM) according to International Myeloma Working Group (IMWG) diagnostic criteria * Participant must have measurable disease defined by any of the following: Serum M-protein level greater than or equal to (\>=) 1.0 gram per deciliter (g/dL); Urine M-protein level \>= 200 milligrams per 24 hours (mg/24 hours); or Light chain MM, for participants without measurable disease in the serum or urine: serum Ig-free light chain (FLC) \>=10 milligrams per deciliter (mg/dL) and abnormal serum Ig kappa-lambda FLC ratio; or if central laboratory assessments are not available, relevant local laboratory measurements must exceed the minimum required level by at least 25 percent (%) * Participant must be relapsed or refractory to established therapies with known clinical benefit in relapsed/refractory MM or be intolerant to established MM therapies and a candidate for teclistamab treatment in the opinion of the treating physician. Prior lines of therapy must include a proteasome inhibitors (PI), an immunomodulatory drug (IMiD), and an anti-CD38 antibody in any order during the course of treatment. Participants who could not tolerate PI, immunomodulatory drugs, or anti-CD38 antibody are allowed * Eastern Cooperative Oncology Group (ECOG) performance status grade of 0 or 1 at screening and immediately before the start of study treatment administration * Woman of childbearing potential must have a negative pregnancy test at screening and within 24 hours prior to the first dose of study treatment using highly sensitive pregnancy test either serum (beta-human chorionic gonadotropin \[beta-hCG\]) or urine Exclusion criteria: * Prior treatment with any B cell maturation antigen (BCMA)-targeted therapy * Toxicities from previous anticancer therapies that have not resolved to baseline levels or to less than or equal to (\=140 mg of prednisone within the 14-day period before the first step-up dose of study treatment (does not include pretreatment medication) * Stem cell transplantation: An allogeneic stem cell transplant within 6 months. Participants who received an allogeneic transplant must be off all immunosuppressive medications for 6 weeks without signs of graft-versus-host disease; Received an autologous stem cell transplant less than or equal (\