FDA Approves Elrexfio for Heavily Pretreated Relapsed/Refractory Multiple Myeloma

The Food and Drug Administration (FDA) approved Elrexfio (elranatamab-bcmm) to treat adults with relapsed or refractory multiple myeloma who previously received four or more lines of therapy.

These four lines of therapy include an immunomodulatory agent, a proteasome inhibitor and an anti-CD38 monoclonal antibody, according to a press release from Pfizer, the manufacturer of the therapy. In particular, Elrexfio is a BCMA-CD3-directed bispecific antibody immunotherapy that is delivered subcutaneously (beneath the skin) and aims to activate T-cells to kill myeloma cells.

“Elrexfio reflects our ongoing commitment to developing scientific breakthroughs that meaningfully improve outcomes for people with cancer,” Angela Hwang, chief commercial officer and president of global biopharmaceuticals business for Pfizer, said in the release. “Discovered at Pfizer, we advanced this therapy from a first-in-patient trial to approval in less than five years because we know that time is life for people living with multiple myeloma.”

This FDA approval was based on findings from the phase 2 MagnetisMM-3 trial, which assessed the efficacy of Elrexfio in 123 patients with heavily pretreated relapsed or refractory multiple myeloma. Of these patients in the trial, 97 received four or more lines of therapy before receiving Elrexfio, according to the release.

In those patients who received four or more lines of therapy, the overall response rate (percentage of patients with complete or partial response to therapy) was 58%, with an estimated 82% who maintained the response to treatment for at least nine months. The median time to first response to treatment was 1.2 months, according to the release.

“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,” according to the release.

Data from MagnetisMM-3 also included 63 patients who received at least four lines of therapy including a BCMA-directed therapy. After a median follow-up of 10.2 months, these patients demonstrated an overall response rate of 33%. In addition, 84% of patients from this group maintained a response to treatment for at least nine months.

Longer-term efficacy data were recently presented, which focused on 123 patients. After a median follow-up of 14.7 months, the objective response rate was 61%. Several outcomes had not yet been reached at follow-up including overall survival (the time from treatment assignment when a patient with cancer is alive), duration of response and progression-free survival (the time during and after treatment when a patient with cancer lives without disease worsening), meaning that the outcome did not occur in more than half of patients in the study.

In patients who responded to treatment, the probability of them maintaining response to treatment at 15 months was 72%, according to the release.

Some patients switched to every-other-week dosing at least six months before researchers assessed data. In these 50 patients, 80% improved or maintained their response to treatment, and 38% of patients achieved a complete response (disappearance of all signs of cancer from treatment) or better after this 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,” MagnetisMM clinical trial investigator Dr. Ajay Nooka, director of the multiple myeloma program at Winship Cancer Institute of Emory University, said in the release. “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.”

The label for Elrexfio contains warnings regarding cytokine release syndrome (which may occur after treatment with immunotherapy) and neurologic toxicity, according to the release. The most common side effects that occurred in at least 20% of patients treated with Elrexfio in the trial included fatigue, cytokine release syndrome, diarrhea, injection site reaction, musculoskeletal pain, upper respiratory tract infection, pneumonia, rash, decreased appetite, nausea, cough and fever.

The most common severe or life-threatening side effects related to laboratory abnormalities include decreases in white blood cells, neutrophils, lymphocytes, hemoglobin and platelets.

“Accessibility is key to unlocking the potential impact of new treatment options,” Jenny Ahlstrom, founder and chief executive officer of the HealthTree Foundation for Multiple Myeloma, said in the release. “Unfortunately, novel therapies for triple-class-exposed multiple myeloma can be out of reach for medically underserved populations. With the approval of Elrexfio, patients have a new off-the-shelf treatment option that can be delivered on an ongoing basis in community clinics, where the majority of patients with multiple myeloma receive their care.”

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