RecruitingPhase 1Drug trialA 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)The purpose of the study is to evaluate safety and tolerability of the combination of cevostamab plus elranatamab and also determine the recommended Phase II regimen (RP2R) for the study treatment. The study consists of a safety lead-in stage, and an expansion stage.