Elranatamab Improves Progression-Free Survival in Relapsed/Refractory Multiple Myeloma

Statistically significant and clinically meaningful improvement in progression-free survival (PFS) compared with standard-of-care therapy in patients with relapsed or refractory multiple myeloma (RRMM) was demonstrated with elranatamab (Elrexfio; Pfizer Inc) in the phase 3 MAGNETISMM-5 trial (NCT05020236).¹ Early analysis of the data reveals the study met its primary end point, with a safety profile consistent with prior experience and no new safety signals identified.¹ These findings further characterize the role of B-cell maturation antigen (BCMA)–directed bispecific antibodies in the management of heavily pretreated RRMM.¹

Unmet Need in Relapsed and Refractory Multiple Myeloma

MM is identified as an incurable plasma cell malignancy characterized by repeated relapse despite treatment with immunomodulatory drugs, proteasome inhibitors, and anti-CD38 monoclonal antibodies.² The disease becomes increasingly refractory over time, with progressive declines in both depth and duration of response as patients advance through successive lines of therapy.² This signifies an unmet need for novel immune-based approaches capable of overcoming treatment resistance in advanced disease.

Mechanism of Action and Immune Targeting

Elranatamab is a BCMA × CD3 bispecific antibody that redirects endogenous T cells to target malignant plasma cells.² Through simultaneously binding BCMA on myeloma cells and CD3 on T cells, elranatamab facilitates T cell–mediated cytotoxicity against malignant plasma cells.² BCMA is an established therapeutic target given its selective expression on plasma cells and minimal expression on normal tissues. These expression characteristics have supported BCMA as a focus of active immunotherapy development in RRMM.²

Clinical Development

Elranatamab, in early clinical development, demonstrated activity in heavily pretreated RRMM populations, providing the foundation for later-stage randomized evaluation.³ These data established the feasibility of subcutaneous administration, a manageable safety profile, and antitumor efficacy in patients with limited remaining treatment options.³

In the phase 2 MagnetisMM trial (NCT04649359), elranatamab demonstrated response rates that supported continued development in phase 3 trials, including in heavily pretreated and triple class–exposed patients.⁴

Bispecific antibody therapy is associated with class-related toxicities, including cytokine release syndrome (CRS), cytopenias, and infections.⁵ These adverse effects are generally manageable with step-up dosing, inpatient monitoring during initiation, and supportive care strategies. Most events occur early in treatment and decrease in frequency with continued dosing.⁵

Regulatory Context

The FDA granted accelerated approval to elranatamab for adults with RRMM who have received multiple prior lines of therapy.⁶ This approval was based on response rates and durability observed in early clinical studies, with confirmatory evidence being evaluated in ongoing randomized trials.⁶

Clinical Implications

Elranatamab represents an important addition to the RRMM treatment armamentarium and may introduce new considerations for practitioners. Strict adherence to step-up dosing schedules and Risk Evaluation and Mitigation Strategy requirements is essential to mitigate CRS and neurologic toxicity risk.¹ Pharmacists can contribute to protocol enforcement, premedication coordination, and inpatient monitoring during initiation.

Infection risk and cytopenias require proactive laboratory monitoring and supportive care management.⁵ Pharmacists may assist in guiding antimicrobial prophylaxis, managing dose interruptions, and educating patients on early signs of infection or toxicity.

As BCMA-directed therapies expand into earlier lines of treatment and are increasingly sequenced with chimeric antigen receptor T-cell therapies and antibody-drug conjugates, pharmacists will play an increasingly important role in optimizing therapy selection and sequencing strategies in relapsed disease.³ The subcutaneous formulation of elranatamab may improve access and reduce infusion center burden, though the complexity of its initiation reinforces the need for structured multidisciplinary coordination led in part by oncology pharmacy teams.⁴

REFERENCES

1. Pfizer’s ELREXFIO significantly improves progression-free survival for double-class exposed patients with relapsed or refractory multiple Myeloma. News release. Pfizer. April 29, 2026. Accessed April 30, 2026. https://www.pfizer.com/news/press-release/press-release-detail/pfizers-elrexfio-significantly-improves-progression-free

2. Ogiya D, Suzuki R, Goto S, et al. Efficacy and safety of bispecific antibodies in multiple myeloma patients with end-stage renal disease undergoing hemodialysis: a case report of elranatamab and a literature review. Ann Hematol. 2025;104(11):6075-6079. doi:10.1007/s00277-025-06689-0

3. Saied G, Halford Z. Engaging a new treatment paradigm: elranatamab in relapsed/refractory multiple myeloma. Ann Pharmacother. 2025;59(5):473-484. doi:10.1177/10600280241281742

4. Lesokhin AM, Tomasson MH, Arnulf B, et al. Elranatamab in relapsed or refractory multiple myeloma: phase 2 MagnetisMM-3 trial results. Nat Med. 2023;29(9):2259-2267. doi:10.1038/s41591-023-02528-9

5. Rais T, Khan A, Riaz R. Elrexfio (elranatamab-bcmm): the game-changer in treatment of multiple myeloma. Rare Tumors. 2023;15:20363613231207483. doi:10.1177/20363613231207483

6. FDA grants accelerated approval to elranatamab-bcmm for multiple. FDA. August 14, 2023. Accessed April 30, 2026. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-accelerated-approval-elranatamab-bcmm-multiple-myeloma?