EXCALIBER-RRMM Trial Results: MRD Negativity and Progression-Free Survival in Relapsed/Refractory Multiple Myeloma

In this segment, Dr. Joseph Mikhael and Dr. Paul Richardson discuss findings from the phase 3 EXCALIBER-RRMM trial, which compared iberdomide plus daratumumab and dexamethasone with bortezomib plus daratumumab and dexamethasone in patients with relapsed/refractory multiple myeloma. Dr. Mikhael highlights the nearly twofold difference in MRD negativity rates between the treatment arms, at 41% versus 21%, and discusses reported PFS figures of 42 months and 20 months, respectively. Dr. Richardson emphasizes the significance of these findings, noting that the increase in MRD negativity was accompanied by a corresponding improvement in PFS. He contrasts this consistency with the more variable relationship between MRD negativity and durability of response observed with some treatment modalities in the relapsed/refractory setting. The experts discuss how these results strengthen the evidence supporting MRD negativity as a potential regulatory endpoint, while highlighting the importance of demonstrating its association with clinically meaningful outcomes. The findings are presented as an important development for MRD-guided regulatory decision-making in multiple myeloma.