Outcomes of elranatamab in relapsed/refractory multiple myeloma: prognostic impact of monocyte count, MyCARe, and
Taku Kikuchi1, Shotaro Sugita2, Ukyo Kondo2
1Department of Hematology, Japanese Red Cross Medical Center, 4-Chōme-1-22 Hiroo, Shibuya-Ku, Tokyo, 150-8935, Japan. taku_k_1123@mac.com.
Background:
Elranatamab, a bispecific antibody targeting B-cell maturation antigen and CD3, has demonstrated efficacy in relapsed/refractory multiple myeloma (RRMM). However, real-world evidence is limited, and prognostic factors have not been sufficiently evaluated.
Methods:
We retrospectively analyzed patients with RRMM receiving elranatamab between June 2024 and July 2025. Responses were assessed using the International Myeloma Working Group criteria. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Prognostic factors were evaluated using univariate log-rank analysis, including R2-ISS at elranatamab initiation (dynamic R2-ISS) and modified MyCARe risk, with positivity defined as any detectable plasma cells in peripheral blood.
Results:
Thirty-seven patients were evaluated (median age, 67 years; prior lines, 5). Median follow-up was 7.5 (median PFS, 9.7) months. One-year OS was 66.3%. The overall response rate was 67.6%, and 45.9% achieved at least a very good partial response. Extramedullary disease, plasma cells in the peripheral blood, and high-risk cytogenetics were adverse features. A baseline monocyte count < 300/µL, high-risk classification by modified MyCARe, and dynamic R2-ISS stage IV were significantly associated with shorter PFS and OS.
Conclusion:
Elranatamab was effective in real-world settings. Baseline monocyte count, modified MyCARe risk, and dynamic R2-ISS may serve as practical prognostic tools.
