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)

Prior treatment

• Prior treatment with cevostamab or another agent targeting fragment crystallizable receptor-like 5 (FcRH5)
• Prior treatment with elranatamab
• Prior allogeneic stem cell transplantation (SCT)

Other illness

• 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
• Known or suspected chronic cytomegalovirus (CMV) and/or Epstein-Barr virus (EBV) infection
• Known history of hemophagocytic lymphohistiocytosis (HLH) or macrophage activation syndrome (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

Lab values

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

Other

• Peripheral motor polyneuropathy of prespecified grade

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