Bristol Myers Squibb disclosed Phase 3 results for mezigdomide in the SUCCESSOR-2 study, showing a substantial progression-free survival improvement when added to carfilzomib and dexamethasone in relapsed or refractory multiple myeloma. BMS reported a 52% reduction in risk of disease progression or death versus the control regimen. In the updated analysis shared ahead of or at ASCO, median PFS rose to 18 months in the mezigdomide arm from 8.3 months with carfilzomib and dexamethasone alone. The company also reported deeper response metrics, with higher complete response and no-trace-of-disease rates in the mezigdomide combination. BMS flagged that severe adverse events were more frequent in the experimental arm, with higher rates of grade 3 or 4 treatment-related adverse events. The company framed the safety profile as consistent with prior mezigdomide experience and characterized it as manageable. The follow-on readout is important because mezigdomide is positioned as a potential successor to established myeloma backbone therapies, aligning with a competitive field increasingly shaped by CELMoDs, bispecific antibodies, and cell therapies.