Comparison of Patient-Reported Outcomes for Elranatamab in MagnetisMM-3 Versus Real-World Physician Choice of Therapy for Triple-Class Refractory Multiple Myeloma

BACKGROUND: Multiple myeloma (MM) impairs function and quality of life, which can be impacted by treatment choices. We compared patient-reported outcomes (PROs) in triple-class refractory (TCR) MM between patients treated with elranatamab (ELRA) and real-world physician's choice of therapy (PCT). PATIENTS AND METHODS: Patients from MagnetisMM-3 (NCT04649359), a phase 2 trial of ELRA monotherapy, were compared with patients from 2 prospective observational studies (MagnetisMM-13, MagnetisMM-14). PROs assessed at 6 monthly visits included the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Version 3.0, European Organization for Research and Treatment of Cancer Multiple Myeloma Questionnaire Version 2.0, European Quality of Life Five Dimension-5 Level, and the Patient Global Impressions of Severity (PGIS) and Change (PGIC). Mixed models for repeated measures estimated adjusted changes from baseline; multiplicity was addressed using Benjamini-Hochberg false discovery rate (FDR). Sensitivity analyses included inverse probability of treatment weighting, multiple imputation under a missing-at-random assumption, and pattern-mixture models to evaluate missing-not-at-random mechanisms. RESULTS: N = 184 ELRA-treated and N = 68 PCT-treated patients with TCR MM were analyzed. Cohorts were similar in age, sex, Eastern Cooperative Oncology Group, and ISS, though ELRA patients were diagnosed earlier (7.2 vs. 5.8 years) and had more prior lines of therapy (mean, 6.1 vs. 4.1). Greater mean improvements from baseline were observed for ELRA versus PCT in several PRO domains after FDR adjustment, including general quality of life (EQ-5D-5L index; visit(V) 6), the Visual Analog Scale (V5), PGIC (V2-V6), disease symptoms (V4), and PGIS (V4-V5). Sensitivity analyses supported the primary findings. CONCLUSION: Patients with TCR MM treated with ELRA demonstrated similar or greater improvements in PROs over 6 months relative to real-world PCT, with results consistent across sensitivity analyses. MAGNETISMM-3 CLINICALTRIALS. GOV IDENTIFIER: NCT04649359.