Elrexfio Improves Progression-Free Survival in Multiple Myeloma Phase 3 Trial

Pfizer announced positive topline results from the phase 3 MagnetisMM-5 trial evaluating Elrexfio (elranatamab) in adults with relapsed or refractory multiple myeloma, showing the treatment helped patients live longer without their disease worsening compared with standard treatment.

How did Elrexfio improve progression-free survival in multiple myeloma?

Results from the MagnetisMM-5 study showed that Elrexfio significantly improved progression-free survival, which means patients lived longer without their cancer growing or spreading, compared with Darzalex (daratumumab) plus Pomalyst (pomalidomide) and dexamethasone.

The improvement was both statistically significant and clinically meaningful, meaning the results were unlikely due to chance and were large enough to matter for patients. The findings were confirmed through an independent review.

At the time of the interim analysis, most patients receiving Elrexfio had not experienced disease progression. The treatment also exceeded the pre-set goal for effectiveness, showing strong early benefit.

Researchers are continuing to follow patients to understand whether Elrexfio can also help people live longer overall, which is another key goal of the study.

These findings suggest that using Elrexfio earlier in treatment may help patients better control their disease after it returns or stops responding to previous therapies.

What is the MagnetisMM-5 trial and who participated?

MagnetisMM-5 is an open-label, multicenter, randomized phase 3 clinical trial designed to compare Elrexfio with standard treatment in patients with relapsed or refractory multiple myeloma.

The study included 497 patients across 26 countries. All participants had previously received at least one treatment, including Revlimid (lenalidomide) and a proteasome inhibitor.

Patients in the Elrexfio group received injections under the skin. Treatment began with two smaller “step-up” doses to help reduce side effects, followed by a regular weekly dose of 76 mg.

If patients responded well to treatment, the dosing schedule could be reduced over time to every two weeks and then every four weeks, making treatment less frequent.

The main goal of the study is to measure progression-free survival. Researchers are also tracking overall survival as a key secondary goal.

What side effects should patients know about with Elrexfio?

The safety findings in this study were consistent with what has been seen in earlier research, and no new safety concerns were identified.

Elrexfio can cause serious side effects, including cytokine release syndrome, which is a reaction that can happen when the immune system becomes very active. Symptoms may include fever of 100.4°F (38°C) or higher, trouble breathing, chills, dizziness, fast heartbeat and headache.

Neurologic side effects can also occur and may include confusion, trouble staying awake, difficulty speaking or thinking, and problems with balance or movement.

Because of these risks, patients receive treatment using a step-up dosing schedule and are monitored in the hospital after early doses.

Other common side effects include tiredness, injection site reactions such as redness or pain, diarrhea, muscle and bone pain, decreased appetite, rash, cough, nausea and fever.

Infections, including upper respiratory infections and pneumonia, may occur and can be serious. Patients may also experience low white blood cell counts and liver problems, which require monitoring during treatment.

References

1. Pfizer Inc. Pfizer’s ELREXFIO significantly improves progression-free survival for double-class exposed patients with relapsed or refractory multiple myeloma. Press release. April 29, 2026.

For more news on cancer updates, research and education, don’t forget to subscribe to CURE®’s newsletters here.