Pfizer’s Elrexfio has taken another step on its path to potential commercial momentum: The drugmaker just announced another phase 3 win for the bispecific antibody, this time as a treatment for patients with relapsed or refractory multiple myeloma (RRMM) whose disease has progressed after first-line treatment.
The topline readout, announced Tuesday, came by way of Pfizer’s MagnetisMM-32 trial, one of multiple ongoing phase 3 trials evaluating Elrexfio as an earlier-line option for RRMM.
According to Pfizer, patients who took Elrexfio after at least one prior line of treatment had a significantly lower risk of disease progression or death compared to an investigator's choice regimen of BMS and AbbVie's Empliciti (elotuzumab) with Bristol's Pomalyst (pomalidomide), Pomalyst with Takeda's Velcade (bortezomib), or Amgen's Kyprolis (carfilzomib), all paired with the steroid dexamethasone.
Patients enrolled in Pfizer's study had previously tried at least one previous line of treatment with anti-CD38 therapy, a category that includes J&J’s Darzalex or Sanofi’s Sarclisa, with Revlimid.
The interim results hit the trial’s primary endpoint of improved progression-free survival (PFS) compared to the three prominent standard of care regimens for RRMM. Pfizer hailed the standard of care control arm as one of the broadest in a BCMA bispecific antibody to date.
At the time of the analysis, more than 75% of patients in the Elrexfio arm had not experienced disease progression or death from any cause, an outcome Pfizer called “significant and clinically meaningful.” Eighteen-month progression-free survival was estimated at 68%, and median PFS has not yet been reached. The drugmaker is still waiting for data on its secondary endpoint—overall survival—to mature for analysis.
Elrexfio's safety profile in the study was consistent with previous trials. Infections rated grade 3 or higher occurred in 27.5% of patients on Elrexfio vs 18.1% of patients on standard regimens. Grade 5 infections were logged in 0.8% of Elrexfio patients versus 1.6% in the control group. Pfizer said prophylactic infection treatment from the beginning of the study helped mitigate infection risk.
Analysts at Citi noted that Elrexfio’s efficacy was right “in line” with its first-in-class competitor and market leader Tecvayli from J&J, which demonstrated a 68.9% PFS at 18-months in a similar study. And in safety, Elrexfio’s 27.5% infection rate was below Tecvayli’s 41.6%, though cross-trial safety comparisons are unreliable. Neither study has reached median PFS yet.
“These findings further strengthen the rationale for moving BCMA-directed therapy earlier in the treatment journey and underscore Elrexfio's potential to help redefine outcomes for patients,” Pfizer's chief oncology officer, Jeff Legos, said in a statement.
Legos added that while earlier-line CD38 and lenalidomide regimens have transformed the multiple myeloma treatment landscape, a growing number of patients have few options when their disease progresses on these therapies. Elrexfio stands to fill that gap.
“The MagnetisMM-32 results are particularly compelling given the rigorous and clinically relevant benchmark of three established standard-of-care regimens,” added C. Ola Landgren, chief of the Myeloma Division and director of the Sylvester Myeloma Institute at the University of Miami Miller School of Medicine.
The topline success for MagnetisMM-32 follows a similar interim victory for Pfizer’s MagnetisMM-5 phase 3, which read out in April. In the 497-patient trial, Elrexfio monotherapy significantly improved PFS in patients who had received at least one prior treatment, including frontline lenalidomide and a proteasome inhibitor (PI). The trial was seen as a significant win for “double-class exposed” patients whose disease is relapsed or refractory.
Pfizer said it plans to submit the latest data to global regulators as evidence for Elrexfio’s value further up the treatment line.
In the first half of 2026, Elrexfio’s sales hit $169 million, a 17% increase over $145 million earned in the first half of 2025. Citi analysts said the earlier-line label expansions in RRMM represent a $1.32 billion opportunity for the drug by 2032.
The FDA initially signed off on Elrexfio in 2023, approving the drug as a later-line treatment for multiple myeloma patients who had tried at least four prior lines of therapy.