RecruitingDrug trialA Study Evaluating the Safety and Efficacy of Multiple Treatments in Participants With Multiple MyelomaCO43923 is a platform study that will evaluate the safety, efficacy, and pharmacokinetics (PK) of multiple treatment combinations, as monotherapy or in combination, in participants with multiple myeloma (MM). The study is designed with the flexibility to open new treatment substudies as new treatments become available. Information regarding the opened substudies are found below.