Elizabeth Aronson Walks Through the Data Supporting Elranatamab Approval in Multiple Myeloma

Elranatamab (Elrexfio) a BCMA-CD3-directed bispecific antibody immunotherapy that is delivered subcutaneously, was granted accelerated approval on August 14, 2023, to treat patients with relapsed or refractory multiple myeloma (RRMM) who have already undergone 4 prior lines of treatment, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody.

Of note, the new agent is the first off-the-shelf, or ready-to-use, fixed-dose subcutaneous BCMA-directed agent approved for this population that has an every-other-week dosing schedule following 24 weeks of weekly treatment.

In an interview with Oncology Nursing News®, Elizabeth Aronson, MSN, FNP-BCN, OCN, who is a clinical nurse practitioner specializing in bone marrow transplant and immune effector cell therapies at Mount Sinai Hospital, walked through the clinical trial data supporting the approval and underscored what stood out to her about the current evidence.

The approval was supported by data from the phase 2 MagnetisMM-3 trial (NCT04649359). This single-arm trial demonstrated that patients with heavily treated RRMM (n = 97) achieved a 58% overall response rate (ORR) with treatment. Further, 82% of responders maintained a response for at least 9 months.

Additionally, long-term efficacy data presented at the 2023 European Hematology Association meeting, showcased a 61% ORR and a median duration of response, overall survival, and prepgression-free survival that had not yet been reached at 14.7 months. Investigators estimated that for the remaining patients, the probability of maintaining a response at 15 months of follow-up was 72%.

According to Aronson, MagnetisMM-3 trial is a unique trial because it allowed patients who were heavily pretreated to enroll. She explained that over 90% of patients who enrolled on the trial were triple-class refractory, meaning that they had already undergone standard-of-care drugs and yet their multiple myeloma had continued to progress. Further, she noted that many studies evaluating BCMA-directed agents do not enroll patients who have already undergone BCMA-directed therapy. However, MagnetisMM-3 did enroll patients who BCMA-targeted therapy refractory, making it different.

Finally, Aronson noted that the toxicity profile with elranatamab was comparable to other bispecific antibodies and CAR T-cell therapies approved for patients with RRMM. In the trial, most patients who developed cytokine release syndrome (CRS), and neurotoxicity had low grade reactions and the toxicities were managed with acetaminophen and tocilizumab (Actemra) supportive care, she said, noting that patients were not requiring intensive care unit admission to manage CRS.

Reference

Pfizer’s ELREXFIO™ receives U.S. FDA accelerated approval for relapsed or refractory multiple myeloma. Pfizer. Press release. August 14, 2023. Accessed September 25, 2023. https://www.pfizer.com/news/press-release/press-release-detail/pfizers-elrexfiotm-receives-us-fda-accelerated-approval