Elranatamab in Relapsed/Refractory Multiple Myeloma: A Multicenter Real-World Study from Türkiye

Background: Elranatamab, a bispecific antibody targeting BCMA and CD3, has demonstrated clinical activity in relapsed/refractory multiple myeloma. Real-world evidence regarding infectious complications and supportive care remains limited. We evaluated the early clinical activity, safety profile, infectious complications, and supportive care practices associated with relapsed/refractory multiple myeloma (RRMM). This study represents one of the first multicenter real-world evaluations of elranatamab in Türkiye. Methods: This multicenter retrospective study included 87 patients with relapsed/refractory multiple myeloma treated with elranatamab. Clinical characteristics, treatment responses, immune-mediated toxicities, infectious complications, and supportive care practices were assessed. Overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) were evaluated. Multivariable analyses were performed to identify factors associated with treatment response and clinical outcomes. Results: At 3 months, ORR was 47.1% in the ITT population, 54.7% in the mITT population, and 83.7% among evaluable patients; corresponding 6-month ORRs were 31.0%, 42.2%, and 81.8%, respectively. The high proportion of patients without landmark response assessments primarily reflected insufficient follow-up, early death, or disease progression. Elevated LDH remained independently associated with lower response probability and inferior clinical outcomes. Cytokine release syndrome (CRS) occurred in 69% of patients, with grade ≥ 3 events in 5.7%, whereas immune effector cell-associated neurotoxicity syndrome (ICANS) was infrequent (4.6%) and no grade ≥ 3 events occurred. Grade ≥ 3 infections occurred in 39% of patients, including CMV events requiring antiviral treatment in 24.1%. No HBV reactivation occurred among patients receiving antiviral prophylaxis. Median PFS and OS were 8.1 and 10.6 months, respectively. Conclusions: Elranatamab demonstrated early clinical activity and a manageable safety profile in a heavily pretreated real-world RRMM population. Infectious complications, including CMV events, remained clinically relevant, emphasizing the importance of supportive care. Longer follow-up is needed to characterize long-term outcomes.