Early Mortality with Bispecific Antibody Therapy in RRMM: An IMWG Immunotherapy Database Real-World Analysis

Recent therapeutic advances, including bispecific antibody therapies (bsAbs) have improved outcomes for patients with relapsed/refractory multiple myeloma (RRMM). However, early mortality (EM) remains a significant challenge, even in the era of novel immunotherapies. We conducted a multicenter, retrospective analysis of real-world patients with RRMM treated with commercial bsAbs to evaluate the incidence and causes of EM. Between May 2022 and June 2025, 441 patients were treated across seven countries. EM, defined as death within 12 months of therapy initiation, occurred in 148 patients (34%) with median time from bsAb initiation to death of 2.87 months (IQR 1.38-6.85). The leading cause of EM was progressive disease (72%), followed by infection (13%); regardless of cause of death 82% had active disease at the time of death. Our findings highlight that despite encouraging efficacy, EM remains high among real-world bsAb recipients, emphasizing the need for improved disease control strategies and supportive care interventions.