Elrexfio receives FDA accelerated approval for relapsed or refractory multiple myeloma – Pfizer

Pfizer Inc. announced the FDA has granted accelerated approval to Elrexfio (elranatamab-bcmm) for the treatment of adult patients with relapsed or refractory multiple myeloma (RRMM) who have received at least four prior lines of therapy, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody.

Approval was based on the results of the single-arm Phase II MagnetisMM-3 trial, and continued approval for this indication is contingent upon verification of clinical benefit in a confirmatory trial(s). Elrexfio is a subcutaneously delivered B-cell maturation antigen (BCMA)-CD3-directed bispecific antibody (BsAb) immunotherapy that binds to BCMA on myeloma cells and CD3 on T-cells, bringing them together and activating the T-cells to kill myeloma cells.

The approval of Elrexfio is based on data from response rates and duration of response. Data from cohort A (n=123) of the Phase II MagnetisMM-3 study (NCT04649359) showed meaningful responses among heavily pretreated RRMM patients who received Elrexfio as their first BCMA-directed therapy. Among the patients in this study who received four or more lines of therapy prior to Elrexfio (n=97), the overall response rate was 58%, with an estimated 82% maintaining the response for at least nine months. The median time to first response was 1.2 months.

This study also established Elrexfio as the first BCMA-directed therapy in the U.S. 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. The label also includes data from MagnetisMM-3 cohort B (n=64). Among the 63 patients in this cohort who received at least four prior lines of therapy, including a BCMA-directed therapy (CAR-T or antibody-drug conjugate), the overall response rate was 33% after a median follow-up of 10.2 months, with an estimated 84% maintaining the response for at least nine months.

In longer-term efficacy data for cohort A (n=123) presented at the 2023 European Hematology Association meeting, the objective response rate was 61%, and median duration of response, overall survival, and progression-free survival had not yet been reached at 14.7 months median follow-up. For the responding patients, the probability of maintaining a response at 15 months was 72%. Among responding patients who switched to every-other-week dosing at least six months prior to the data cut-off date (n=50), 80% maintained or improved their response after the switch, with 38% attaining a complete response or better after the switch.

Most multiple myeloma patients will experience relapse or resistance of their disease to treatment, often facing increased symptom burden and lowering their chance of surviving longer with each attempted line of therapy,” said MagnetisMM clinical trial investigator Ajay Nooka, MD, MPH, Director of the Multiple Myeloma Program at Winship Cancer Institute of Emory University. “By offering durable clinical response with an established safety profile and the convenience of subcutaneous administration, Elrexfio provides a much-needed new option for heavily pre-treated multiple myeloma patients who are struggling with relapsed myeloma.”