A Study in Participants With Relapsed or Refractory Multiple Myeloma for IBI3003

This study is an open, multicenter, randomized controlled phase III clinical trial aimed at evaluating the efficacy and safety of IBI3003 compared to the investigator's choice regimen (DPd or PVd) in participants with relapsed or refractory multiple myeloma who have previously received 1-4 lines of therapy and have been exposed to three classes of drugs (proteasome inhibitors, immunomodulators, and anti-CD38 monoclonal antibodies). The plan is to enroll approximately 255 participants, who will be randomly assigned to the experimental group and the control group in a 2:1 ratio. Approximately 170 participants in the experimental group will receive IBI3003 treatment, while about 85 participants in the control group will receive the investigator's choice of treatment (DPd or PVd). Participants in the experimental group can discontinue medication for observation after meeting the criteria for stopping treatment. During the discontinuation period, if they meet the re-treatment criteria, following discussion between the investigator and the sponsor, and based on the participant's preference, IBI3003 re-treatment may be given until the criteria for terminating treatment are met.