A Study Evaluating the Safety, Pharmacokinetics, and Activity of the Combination of Cevostamab and Elranatamab in Participants With Relapsed or Refractory Multiple Myeloma (R/R MM)

Inclusion Criteria:

• Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1

• Diagnosis of R/R MM per IMWG criteria

• For female participants of childbearing potential: agreement to remain abstinent oruse contraception

• For male participants: agreement to remain abstinent or use a condom

Exclusion Criteria:

• Prior treatment with cevostamab or another agent targeting fragment crystallizablereceptor-like 5 (FcRH5)

• Prior treatment with elranatamab

• Prior allogeneic stem cell transplantation (SCT)

• Absolute plasma cell count exceeding 500 per milliliter (mL) or 5% of the peripheralblood white cells

• Diagnosis of Waldenström macroglobulinemia or polyneuropathy, organomegaly,endocrinopathy, monoclonal gammopathy, skin changes (POEMS) syndrome

• Participants with known history of amyloidosis

• History of autoimmune disease

• History of confirmed progressive multifocal leukoencephalopathy

• Peripheral motor polyneuropathy of prespecified grade

• Known or suspected chronic cytomegalovirus (CMV) and/or Epstein-Barr virus (EBV)infection

• Known history of hemophagocytic lymphohistiocytosis (HLH) or macrophage activationsyndrome (MAS)

• Acute or chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection

• Human immunodeficiency virus (HIV) seropositivity

• History of central nervous system (CNS) myeloma disease

• Significant cardiovascular disease