Pfizer Inc. announced its investigational cancer immunotherapy, elranatamab, received Breakthrough Therapy Designation from the US Food and Drug Administration (FDA) for the treatment of people with relapsed or refractory multiple myeloma (RRMM). Elranatamab is a B-cell maturation antigen (BCMA)-CD3-targeted bispecific antibody (BsAb).
“The FDA’s Breakthrough Designation recognizes the potential of elranatamab as an innovative medicine for people with multiple myeloma whose disease has relapsed or is refractory to existing treatments, which at present leaves very few avenues for staving off this currently incurable cancer,” said Chris Boshoff, M.D., Ph.D., chief development officer, oncology and rare disease, Pfizer Global Product Development. “This marks Pfizer’s twelfth FDA Breakthrough Therapy Designation in Oncology, a testament to our relentless commitment to developing transformational cancer medicines in areas of high unmet need. We look forward to working with the FDA to accelerate the development of this therapy.”
The FDA’s Breakthrough Therapy Designation is intended to expedite the development and review of a medicine that is intended to treat a serious or life-threatening disease and preliminary clinical evidence indicates the drug may demonstrate substantial improvement over existing therapies.
BsAbs are a novel form of cancer immunotherapy that bind to and engage two different targets at once. One arm binds directly to specific antigens on cancer cells and the other arm binds to T-cells, bringing both cell types together. Elranatamab is designed to bind to BCMA, which is highly expressed on the surface of multiple myeloma (MM) cells, and the CD3 receptor found on the surface of T-cells, bridging them together and activating the T-cells to kill the myeloma cells. The binding affinity of elranatamab for BCMA and CD3 has been engineered to elicit potent T-cell mediated anti-myeloma activity. Elranatamab is administered subcutaneously, which offers more convenience over intravenous administration, and may mitigate the risk of potential adverse events, such as cytokine release syndrome (CRS).
The Breakthrough Therapy Designation is based on six-month follow-up data from cohort A (n=123) of MagnetisMM-3, an open-label, multicenter, single arm, phase 2 study evaluating the safety and efficacy of elranatamab monotherapy in patients with RRMM. Patients received subcutaneous (SC) elranatamab 76 mg weekly (QW) with a 2-step-up priming dose regimen administered during the first week. The study showed elranatamab demonstrated a manageable safety profile, and at a median follow-up of 6.8 months, patients achieved an overall response rate (ORR) of 61.0%. Among responders, there was 90.4% probability of maintaining a response =6 months. The most common treatment-emergent adverse event (TEAE) regardless of causality was CRS (57.9%), with the majority of events reported being either Grade 1 (43.2%) or Grade 2 (14.2%). Updated data from MagnetisMM-3 will be presented at the 64th American Society of Hematology Annual Meeting and Exposition 2022 (ASH 2022), taking place December 10-13, 2022, in New Orleans.
MagnetisMM-3 is part of the robust MagnetisMM clinical research program, which has registration-intent trials planned or ongoing that explore elranatamab both as monotherapy and in combination with standard or novel therapies, spanning multiple patient populations from newly diagnosed multiple myeloma (NDMM), double-class exposed disease and RRMM.
In addition to the Breakthrough Therapy Designation, elranatamab has been granted Orphan Drug Designation by the FDA and the European Medicines Agency (EMA) for the treatment of MM. The FDA and EMA have granted elranatamab Fast Track Designation and the PRIME scheme, respectively, for the treatment of patients with RRMM. The UK Medicines and Healthcare Products Regulatory Agency (MHRA) has also granted elranatamab Innovative Medicine Designation and the Innovation Passport, for the treatment of MM.
MM is a blood cancer that affects plasma cells made in the bone marrow. Healthy plasma cells make antibodies that help the body fight infection. According to the latest figures available, there are over 34,000 new cases of MM diagnosed annually in the US and 176,000 globally. Despite treatment advances, MM remains incurable. The median overall survival is just over five years, and most patients receive four or more lines of therapy