Pfizer reports Phase 3 MagnetisMM-5 results showing ELREXFIO significantly improves progression-free survival in relapsed or refractory multiple myeloma patients.
Written By: Karthik Teja Macharla, PharmD
Reviewed By: Pharmacally Editorial Team
Pfizer Inc. has reported positive topline results from the Phase 3 MagnetisMM-5 trial evaluating ELREXFIO as a monotherapy in adults with relapsed or refractory Multiple Myeloma who had received at least one prior line of therapy.
The study met its primary endpoint, demonstrating a statistically significant and clinically meaningful improvement in progression-free survival compared with standard-of-care daratumumab, pomalidomide, and dexamethasone, with results exceeding the predefined interim efficacy threshold and most treated patients remaining progression-free at the time of analysis.
Safety findings were consistent with the drug’s known profile.
The randomized, open-label, multicenter study enrolled 497 patients across 26 countries who had previously received treatments including lenalidomide and a proteasome inhibitor.
ELREXFIO was administered subcutaneously with step-up priming doses followed by weekly dosing, with reduced frequency in patients achieving sustained responses.
Overall survival, a key secondary endpoint, remains immature, and the trial is ongoing, with detailed data planned for presentation at a future medical meeting and discussions with regulators.
ELREXFIO is a bispecific antibody targeting B-cell maturation antigen on myeloma cells and CD3 on T cells, activating T cells to kill malignant plasma cells. It is approved in more than 35 countries, including accelerated approval in the United States for patients with at least four prior lines of therapy and conditional authorization in the European Union for those with at least three prior therapies.
The MagnetisMM-5 study (NCT05020236) is part of a broader development program evaluating the therapy across multiple treatment settings, including earlier lines and combination approaches.
Multiple myeloma remains an incurable blood cancer and the second most common globally, with approximately 36,000 new cases annually in the United States and over 187,000 worldwide. Most patients eventually relapse, and outcomes remain limited, with about 40% not surviving beyond five years.
The disease is associated with significant clinical burden, including fatigue, bone pain, and increased infection risk. Pfizer’s oncology leadership indicated that these findings support the potential for ELREXFIO to be used earlier in treatment, building on prior evidence of durable responses in heavily pretreated patients.
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About the Writer
Karthik Teja Macharla, PharmD is a Pharm.D. graduate with a strong interest in clinical research, pharmacovigilance, and medical writing. In his words, he is passionate about converting complex medical information into clear, evidence-based scientific communication, committed to contributing to patient safety and advancing healthcare through accurate and impactful medical content.