RecruitingPhase 3Drug trialA Study to Evaluate Mezigdomide, Bortezomib and Dexamethasone (MEZIVd) Versus Pomalidomide, Bortezomib and Dexamethasone (PVd) in Participants With Relapsed or Refractory Multiple Myeloma (RRMM)The purpose of this study is to compare the efficacy and safety of mezigdomide (CC-92480), bortezomib and dexamethasone (MeziVd) versus pomalidomide, bortezomib and dexamethasone (PVd) in participants with relapsed or refractory multiple myeloma (RRMM) who received between 1 to 3 prior lines of therapy and who have had prior lenalidomide exposure.