RecruitingPhase 1ProcedureMezigdomide (CC-92480) Post Idecabtagene Vicleucel in Treating Patients With Relapsed Multiple MyelomaThis phase I trial studies the safety, side effects, best dose and effectiveness of mezigdomide (CC-92480) when given after idecabtagene vicleucel (Abecma chimeric antigen receptor \[CAR\] T-cell therapy) in patients with multiple myeloma that has come back after a period of improvement (relapsed). CC-92480 works by binding to a protein called CRBN that triggers the breakdown of proteins: Ikaros and Aiolos, leading to cell death in multiple myeloma cells. Giving mezigdomide after Abecma CAR T cell therapy may extending the amount of time that the CAR T cells persist in the body in patients with relapsed multiple myeloma.