Pfizer’s Elrexfio Improves Progression-Free Survival in Phase 3 Myeloma Trial

Pfizer Inc. announced positive topline results from the Phase 3 MagnetisMM-5 trial evaluating elranatamab (brand name Elrexfio) in patients with relapsed or refractory multiple myeloma (RRMM).

The study met its primary endpoint at interim analysis, demonstrating a statistically significant and clinically meaningful improvement in progression-free survival (PFS) compared with standard-of-care therapy consisting of daratumumab, pomalidomide, and dexamethasone. The results exceeded the pre-specified hazard ratio threshold, with most Elrexfio-treated patients remaining progression-free at the time of analysis.

How does Elrexfio compare to standard of care?

Elrexfio, a BCMA-targeting bispecific antibody, was evaluated as a monotherapy against a widely used triplet regimen anchored by daratumumab.

Elrexfio was designed to link to BCMA, which is highly expressed on the surface of MM cells. The CD3 receptor on the surface of T-cells then connects and activates them to kill myeloma cells. The binding affinity of Elrexfio for BCMA and CD3 was developed to induce potent T-cell mediated anti-myeloma activity.

The findings suggest that Elrexfio may offer a competitive—and potentially superior—option in earlier lines of therapy, particularly for patients previously exposed to both immunomodulatory drugs and proteasome inhibitors (so-called “double-class exposed” patients).

Importantly, the safety profile remained consistent with prior studies, and no new safety signals were identified, reinforcing its clinical manageability.

Why is PFS important in multiple myeloma?

Multiple myeloma remains an incurable hematologic malignancy characterized by cycles of remission and relapse. Improving PFS is a key therapeutic goal, as it delays disease progression and the need for subsequent treatments.

Globally, multiple myeloma accounts for more than 187,000 cases annually, with many patients eventually developing refractory disease. Despite advances, long-term survival remains limited, and quality of life is often significantly impacted by symptoms such as bone pain, fatigue, and infection risk.

In this context, extending PFS—especially earlier in the disease course—can translate into meaningful clinical benefit.

What is Next for the MagnetisMM Program?

While the interim PFS results are promising, the MagnetisMM-5 trial is ongoing, with overall survival (OS) as a key secondary endpoint. These data are not yet mature.

Pfizer plans to present detailed findings at an upcoming medical congress and engage with regulatory authorities regarding potential label expansion. The broader development program also includes the Phase 3 MagnetisMM-32 study, which is evaluating Elrexfio in patients previously treated with daratumumab in frontline settings.

Could Elrexfio move earlier in treatment lines?

Elrexfio is already approved in more than 35 countries, including here in the US, where it received accelerated approval for heavily pretreated RRMM patients.

The MagnetisMM-5 results strengthen the case for moving Elrexfio into earlier lines of therapy, either as monotherapy or in combination regimens. This aligns with a broader trend in oncology to deploy highly active agents earlier, where they may have greater impact on disease trajectory.

If supported by OS data, Elrexfio could emerge as a foundational therapy in multiple myeloma, particularly for patients with limited options after relapse.

References

1. A Study to Learn About the Study Medicine Elranatamab Alone and With Daratumumab in People with Multiple Myeloma Who Have Received Other Treatments (MAGNETISMM-5). Clinicaltrials.gov. Xavier Leleuhttps://clinicaltrials.gov/study/NCT05020236
2. Leleu, X., Shinsuke, I., Ola Landgren C. (2023 Feb 22). Pfizer’s Elranatamab Receives FDd EMA Filing Acceptance. News release. Pfizer. Accessed April 29, 2026. https://investors.pfizer.com/Investors/News/news-details/2023/Pfizers-Elranatamab-Receives-FDA-and-EMA-Filing-Acceptance/default.aspx.
3. Nooka, A., Lesokhin, A., Mohty, M., et al. (2023 Oct 4). Elranatamab in relapsed or refractory multiple myeloma (MagnetisMM-1), Nature Medicine: https://www.sciencedirect.com/science/article/pii/S2531137923009410