Pfizer's ELREXFIO Shows Significant Progression-Free Survival Improvement in Multiple Myeloma Phase 3 Trial
Decision brief
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Pfizer's ELREXFIO meets primary endpoint in MagnetisMM-5 Phase 3 trial, showing statistically significant progression-free survival improvement for relapsed multiple myeloma patients.
Key questions this brief answers
- What did the MagnetisMM-5 trial achieve?
- When was ELREXFIO first approved by the FDA?
- How many patients were enrolled in the MagnetisMM-5 trial?
- What safety findings were reported in the interim analysis?
Pfizer's ELREXFIO (elranatamab) achieved its primary endpoint in the Phase 3 MagnetisMM-5 trial, demonstrating a statistically significant improvement in progression-free survival versus standard care for patients with relapsed or refractory multiple myeloma. The company announced results on April 29, 2026.
Contents11 sections
Key Takeaways
- ELREXFIO met its primary endpoint with statistically significant progression-free survival improvement versus daratumumab plus pomalidomide and dexamethasone in the MagnetisMM-5 trial (NCT05020236)
- The safety profile remained consistent with known data, with no new safety signals identified at the interim analysis of 497 patients across 26 countries
- FDA granted accelerated approval to ELREXFIO in August 2023 for heavily pretreated multiple myeloma based on Phase 2 MagnetisMM-3 data showing 57.7% objective response rate
- Pfizer will discuss results with global regulators and submit data for presentation at an upcoming medical conference
What Did the MagnetisMM-5 Trial Evaluate?
The MagnetisMM-5 trial is a Phase 3, open-label, multicenter, randomized study evaluating ELREXFIO monotherapy versus the standard-of-care combination of daratumumab, pomalidomide, and dexamethasone (DPd) in adults with relapsed or refractory multiple myeloma. Patients enrolled had received at least one prior line of therapy, including lenalidomide and a proteasome inhibitor.
The trial enrolled 497 participants across 26 countries. Patients in the ELREXFIO arm received subcutaneous injections following a step-up dosing regimen: 12 mg on day 1, 32 mg on day 4, and 76 mg on day 8 of the first cycle, followed by maintenance dosing.
What Were the Primary Efficacy Results?
The interim analysis demonstrated that ELREXFIO provided a statistically significant and clinically meaningful improvement in progression-free survival (PFS) compared to the DPd control arm. The PFS results exceeded the pre-specified interim analysis target hazard ratio for efficacy, with most ELREXFIO-treated patients remaining progression-free at the time of analysis.
The trial continues to follow patients for overall survival, a key secondary endpoint. The overall survival data were not yet mature at the time of the interim PFS analysis.
How Did the Safety Profile Compare?
The safety and tolerability of ELREXFIO in MagnetisMM-5 remained consistent with its established safety profile from earlier trials. No new safety signals emerged during the interim analysis.
ELREXFIO carries a Boxed Warning for cytokine release syndrome (CRS) and neurologic toxicity, including immune effector cell-associated neurotoxicity syndrome (ICANS). The drug is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS).
What Is ELREXFIO's Regulatory History?
The FDA granted accelerated approval to ELREXFIO on August 14, 2023, for adult patients with relapsed or refractory multiple myeloma who had received at least four prior lines of therapy. The approval was based on results from the Phase 2 MagnetisMM-3 trial, which demonstrated a 57.7% objective response rate.
The MagnetisMM-5 results provide the randomized controlled trial data typically required for full approval and potential label expansion. Pfizer has stated it will discuss the findings with global health authorities to determine next steps for regulatory submissions.
How Does This Impact the Multiple Myeloma Market?
Multiple myeloma affects approximately 35,000 new patients annually in the United States. The majority of patients eventually relapse despite initial treatment success. Patients who have been exposed to two or more prior drug classes represent a significant unmet need with limited therapeutic options.
ELREXFIO competes in the BCMA-targeted therapy space, which includes other bispecific antibodies and CAR-T cell therapies. As an off-the-shelf subcutaneous injection, ELREXFIO offers potential advantages in treatment initiation time compared to personalized CAR-T therapies, which require manufacturing time.
| Trial | Phase | Population | Key Result |
|---|---|---|---|
| MagnetisMM-3 | 2 | 4+ prior lines | 57.7% ORR; FDA accelerated approval (2023) |
| MagnetisMM-5 | 3 | 1+ prior line | Significant PFS improvement vs DPd (2026) |
What Are Pfizer's Next Steps?
Pfizer will present complete MagnetisMM-5 data at an upcoming medical conference. The company has not announced specific timelines for regulatory submissions based on these Phase 3 results.
Beyond MagnetisMM-5, Pfizer continues to evaluate ELREXFIO in earlier lines of therapy and combination settings. The company is also investigating the combination of ELREXFIO with daratumumab in a separate cohort of the MagnetisMM-5 study.
Frequently Asked Questions
What did the MagnetisMM-5 trial achieve?
The Phase 3 MagnetisMM-5 trial met its primary endpoint, demonstrating that ELREXFIO provided a statistically significant and clinically meaningful improvement in progression-free survival compared to daratumumab plus pomalidomide and dexamethasone in patients with relapsed or refractory multiple myeloma.
When was ELREXFIO first approved by the FDA?
The FDA granted accelerated approval to ELREXFIO on August 14, 2023, for adults with relapsed or refractory multiple myeloma who had received at least four prior lines of therapy, based on response data from the Phase 2 MagnetisMM-3 trial.
How many patients were enrolled in the MagnetisMM-5 trial?
The MagnetisMM-5 trial enrolled 497 patients across 26 countries. Participants were randomized to receive either ELREXFIO monotherapy or the standard-of-care combination of daratumumab, pomalidomide, and dexamethasone.
What safety findings were reported in the interim analysis?
The interim analysis found no new safety signals for ELREXFIO. The safety profile remained consistent with established data from earlier trials. ELREXFIO carries a Boxed Warning for cytokine release syndrome and neurologic toxicity, and is available only through a Risk Evaluation and Mitigation Strategy program.
Primary Sources
- Pfizer Press Release: Pfizer's ELREXFIO Significantly Improves Progression-Free Survival in Phase 3 MagnetisMM-5 Trial (April 29, 2026)
- ClinicalTrials.gov: Study of Elranatamab (PF-06863135) Monotherapy and in Combination in Participants With Relapsed/Refractory Multiple Myeloma (MagnetisMM-5) (NCT05020236)
- FDA: FDA Grants Accelerated Approval to Elranatamab-bcmm for Multiple Myeloma (August 14, 2023)
- FDA Approval Letter for ELREXFIO (elranatamab-bcmm) (August 14, 2023)
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