Real-world effectiveness and safety of elranatamab in patients with relapsed/refractory multiple myeloma: Preliminary results from the prospective, non-interventional MagnetisMM-16 study.

e19507 Background: Elranatamab is a B-cell maturation antigen–CD3 bispecific antibody approved for the treatment of adult patients with relapsed or refractory multiple myeloma (RRMM) in several countries. The efficacy and safety of elranatamab were demonstrated in previous clinical trials, and real-world data for elranatamab are currently being accumulated. This interim analysis provides an early look into the results from a real-world primary data collection study of elranatamab in patients with RRMM. Methods: MagnetisMM-16 (EUPAS106401) is a prospective, international, multicenter, non-interventional post-authorization safety study evaluating the effectiveness and safety of elranatamab in patients aged ≥18 years with RRMM treated in real-world settings. Patients are being recruited from hematology/oncology clinics, primary care settings, and academic centers in the United Kingdom, Germany, Spain, and Italy. Investigators were asked in the study protocol to follow recommendations in the local health authority–approved product label, including infection precautions and antimicrobial prophylaxis. This interim analysis is based on a September 15, 2025 data cut and describes preliminary results. Results: A total of 52 patients were included in the analysis. The median age of patients was 70.0 years (range, 48.0-87.0), 59.6% were male, and 88.5% were white. The patients were heavily pre-treated with more than half of the patients (61.5%) receiving ≥4 prior lines of therapy, 94.2% were double-class exposed to prior anti-CD38 and proteasome inhibitor, and 84.6% were triple-class exposed to prior anti-CD38, proteasome inhibitor, and immunomodulatory therapy. International Staging System disease stage at baseline was reported for 32 patients, 46.9% (n=15) had stage III and 34.4% (n=11) had stage II disease. The most common (≥10%) comorbidities were hypertension (32.6%), atrial fibrillation (16.3%), chronic kidney disease (11.6%), and type 2 diabetes mellitus (14.0%). Conclusions: Real-world effectiveness and safety data for elranatamab will be presented for this heavily pre-treated RRMM patient population at the congress. Clinical trial information: EUPAS106401.