A Study to Evaluate the Efficacy of Cemsidomide + Dexamethasone in Participants With Relapsed/Refractory Multiple Myeloma

This trial is testing a new drug called cemsidomide combined with a steroid (dexamethasone) in people with multiple myeloma — a cancer of blood plasma cells — that has come back or stopped responding to previous treatments. **You may be eligible if...** - You are 18 or older with a confirmed diagnosis of multiple myeloma - Your myeloma has come back or stopped responding to treatment - You have already tried at least 3 different treatment regimens, including an immunomodulatory drug, a proteasome inhibitor, an anti-CD38 antibody, and a T-cell engager or CAR-T cell therapy - Your organs (liver, kidneys, heart) are functioning adequately - Side effects from previous treatments have mostly cleared up **You may NOT be eligible if...** - You have not yet tried the required previous treatments - You are pregnant or planning to become pregnant - Your organ function does not meet the study requirements Talk to your doctor to see if this trial is right for you.