Elrexfio (elranatamab) meets primary endpoint of progression-free survival (PFS) in relapsed/refractory myeloma vs three standard of care regimens: elotuzumab, pomalidomide and dexamethasone (EloPd); pomalidomide, bortezomib and dexamethasone (PVd); or carfilzomib and dexamethasone (Kd).

On Tuesday, October 27, Pfizer announced positive topline results from the Phase 3 MagnetisMM-32 trial in a press release. ELREXFIO® (elranatamab) monotherapy met its primary endpoint of progression-free survival (PFS) in adults with relapsed or refractory multiple myeloma (RRMM) previously treated with an anti-CD38 therapy and lenalidomide.

At a prespecified interim efficacy analysis, Elrexfio (elranatamab) demonstrated a statistically significant and clinically meaningful reduction in the risk of disease progression or death compared with investigator’s choice of three established regimens: elotuzumab, pomalidomide and dexamethasone (EloPd); pomalidomide, bortezomib and dexamethasone (PVd); or carfilzomib and dexamethasone (Kd). PFS was assessed by blinded independent central review (BICR).

Median PFS had not been reached in the elranatamab group at the time of analysis. More than 75% of patients receiving elranatamab had not experienced disease progression or death from any cause, and the estimated PFS rate at 18 months was 68%. Overall survival (OS), a key secondary endpoint, remains immature, and follow-up will continue to the next prespecified OS analysis.

Trial design and safety findings

MagnetisMM-32 is an open-label, multicenter, randomized Phase 3 study involving 523 adults across 26 countries. Participants with RRMM received at least one prior line of treatment that included an anti-CD38 therapy, such as daratumumab or isatuximab, and lenalidomide.

Patients received subcutaneous elranatamab using two step-up priming doses followed by weekly doses in 28-day cycles, with dosing subsequently transitioning to every two weeks and then monthly. The primary endpoint was PFS assessed by BICR, and OS was the key secondary endpoint.

The safety profile was consistent with elranatamab’s previously established profile, and no new safety signals were identified. Grade 3 or higher infections occurred in 27.5% of patients receiving elranatamab, compared with 18.1% of patients receiving investigator’s choice. Grade 5 infections, classified as fatal, occurred in 0.8% and 1.6% of patients, respectively. The press release did not specify whether this difference in Grade 5 infections was statistically significant.

Pfizer reported that infection-prophylaxis measures implemented from the beginning of the study helped mitigate infection risk, including the risk of severe infections.

Potential implications for treatment

The findings address a treatment setting of growing clinical importance: patients whose multiple myeloma progresses after anti-CD38 therapy and lenalidomide, treatments commonly used earlier in the disease course. These patients may face limited treatment options as their disease advances.

Elrexfio (elranatamab) is a B-cell maturation antigen (BCMA)-CD3-directed bispecific antibody immunotherapy administered by subcutaneous injection. It binds to BCMA on myeloma cells and CD3 on T cells, activating T cells to kill myeloma cells.

The MagnetisMM-32 findings add to the evidence supporting the evaluation of Elrexfio (elranatamab) monotherapy in earlier lines of treatment for RRMM. Pfizer also cited positive topline results from the Phase 3 MagnetisMM-5 study. Other ongoing studies, including MagnetisMM-6, MagnetisMM-7 and ElLen (IFM 2025-01), are evaluating Elrexfio (elranatamab) in additional multiple myeloma treatment settings, including newly diagnosed disease.

Regulatory status and next steps

Pfizer plans to submit the MagnetisMM-32 results to global health authorities. Detailed findings are expected to be presented at a future medical meeting and submitted for publication.

In the United States, Elrexfio (elranatamab) has accelerated approval for adults with RRMM who have received at least four prior lines of therapy, including a proteasome inhibitor, an immunomodulatory agent and an anti-CD38 monoclonal antibody.  

In the European Union, it has conditional marketing authorization for adults who have received at least three prior therapies and whose disease progressed on their most recent treatment.

The MagnetisMM-32 results do not, by themselves, change Elrexfio’s (elranatamab) existing approved indications. Further review of the detailed clinical data and regulatory assessments will be needed to determine whether the findings support expanded use.

Important safety information

Elrexfio (elranatamab) carries a boxed warning for cytokine release syndrome (CRS) and serious or life-threatening neurologic problems. CRS can be fatal. The treatment can also cause severe or life-threatening infections, decreased blood cell counts, and liver abnormalities.

Because of the risk of CRS, Elrexfio requires step-up dosing and specific monitoring and risk-mitigation measures. In the United States, it is available through the Elrexfio Risk Evaluation and Mitigation Strategy (REMS) Program.

Full prescribing information (including Boxed Warning) for Elrexfio (elranatamab) is available online.

References:

Pfizer’s ELREXFIO Outperforms Standard Regimens and Meets Primary Endpoint in Phase 3 Study in Relapsed or Refractory Multiple Myeloma. Pfizer press release. October 27, 2026.

Risk Evaluation and Mitigation Strategies (REMS). U.S. Food and Drug Administration.

Elrexfio (elranatamab) Prescribing Information. Pfizer Laboratories Div Pfizer Inc.