Bristol Myers Squibb shared efficacy results for mezigdomide from the Phase 3 SUCCESSOR-2 trial in relapsed or refractory multiple myeloma. In the analysis of 479 patients, adding mezigdomide to Amgen’s Kyprolis and dexamethasone reduced progression or death risk by 52% and nearly doubled median progression-free survival. BMS reported average PFS of 18 months with mezigdomide versus 8.3 months in the control arm. The company also highlighted nearly triple the complete response rate (26.7% versus 8.9%) and said overall survival signals are immature, with curves separating early. Safety was a key point in the disclosure, with grade 3 or 4 treatment-related adverse events reported in 83.7% of patients on the mezigdomide regimen versus 56.5% in the control group. BMS said it plans to discuss the data with the FDA, as iberdomide remains under consideration in the same indication.