Pfizer’s Elrexfio Meets Phase 3 Endpoint in Earlier-Line Myeloma Study

Pfizer announced Oct. 27 that Elrexfio met the primary endpoint in a Phase 3 trial of relapsed or refractory multiple myeloma after at least one prior treatment line, earlier than its current U.S. indication.

MagnetisMM-32 enrolled 523 adults across 26 countries in a randomized, open-label study. Participants had received lenalidomide and an anti-CD38 therapy, including drugs such as daratumumab or isatuximab. Progression-free survival, assessed by blinded independent central review, was the primary endpoint.

At a prespecified interim efficacy analysis, the study met that endpoint. More than 75% of patients given Elrexfio had not experienced disease progression or death. Estimated progression-free survival was 68% at 18 months; median progression-free survival had not been reached.

Elrexfio lowered the risk of progression or death relative to one of three regimens selected by investigators: elotuzumab, pomalidomide and dexamethasone; pomalidomide, bortezomib and dexamethasone; or carfilzomib and dexamethasone.

Grade 3 or higher infections occurred in 27.5% of Elrexfio patients, compared with 18.1% among those receiving the comparison regimens. The grade 5 infection rates were 0.8% for Elrexfio and 1.6% for the investigator-selected regimens. Overall-survival data remain immature, and follow-up will continue.

For U.S. adults whose myeloma has relapsed or resisted treatment, Elrexfio is indicated after at least four treatment lines, including drugs from the proteasome-inhibitor, immunomodulatory-agent and anti-CD38-antibody classes. Pfizer plans to submit the results to health authorities worldwide and present detailed findings at a future medical meeting.