The US Food and Drug Administration (FDA) granted accelerated approval to elranatamab-bcmm (ELREXFIO) for adults with relapsed or refractory multiple myeloma (MM) who have received at least four prior lines of therapy, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody.
The bispecific antibody received Breakthrough Therapy Designation from the FDA in November 2022. The FDA granted priority review to the Biologics License Application in February 2023.
The approval is based upon results from the single-arm phase II MagnetisMM-3 trial and continued approval is contingent upon verification of clinical benefit in confirmatory trials, according to a news release from Pfizer, the manufacturer of elranatamab-bcmm.
Data from cohort A of the phase II MagnetisMM-3 trial showed “meaningful responses” in patients with heavily pretreated relapsed or refractory MM who received elranatamab-bcmm—which targets BCMA and CD3—as their first BCMA-directed therapy, officials said. The overall response rate (ORR) was 58% in cohort A, which included patients who received four or more lines of therapy prior to elranatamab-bcmm. The median time to first response was 1.2 months. The ORR was 33% in cohort B, which included patients who received at least four prior lines of therapy, including a BCMA-directed therapy.
“This study also established ELREXFIO as the first BCMA-directed therapy in the [United States] with once-every-other-week dosing for responding patients after 24 weeks of weekly therapy, which means less time at the clinic and potentially greater long-term treatment tolerability,” officials said in the release.
MagnetisMM-5, a confirmatory trial that includes 854 patients with double-class exposed relapsed or refractory MM, was initiated in 2022 to collect further safety and efficacy data.
The label for elranatamab-bcmm contains a Boxed Warning for cytokine release syndrome (CRS) and neurologic toxicity, including immune effector cell-associated neurotoxicity syndrome (ICANS), in addition to warnings and precautions for infections, neutropenia, hepatotoxicity and embryo-fetal toxicity, officials said in the news release.
Due to the risk of CRS and neurotoxicity events such as ICANS, elranatamab-bcmm is available only through a restricted program called the ELREXFIO Risk Evaluation and Mitigation Strategy, officials said.