The U.S. Food and Drug Administration (FDA) has granted priority review to the Biologics License Application (BLA) for elranatamab for the treatment of patients with relapsed/refractory multiple myeloma (MM).
The new FDA decision follows its granting of Breakthrough Therapy Designation to elranatamab in November 2022, and its Orphan Drug Designation for the treatment of MM.
The BLA for elranatamab, an investigational B-cell maturation antigen (BCMA) CD3-targeted bispecific antibody, is primarily based on data from cohort A (BCMA-naïve; n=123) of MagnetisMM-3, an ongoing, open-label, multicenter, single-arm, phase II study designed to evaluate the safety and efficacy of elranatamab monotherapy in patients with relapsed/refractory MM. The data were presented at the 64th American Society of Hematology Annual Meeting and Exposition in December 2022.
Patients enrolled in MagnetisMM-3 represent a heavily pretreated population, who previously received at least three classes of therapies, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody.
With a median follow up of 10.4 months, patients who received elranatamab as their first BCMA-targeted therapy achieved an objective response rate of 61%, with an 84% probability of maintaining the response at nine months.
The MagnetisMM-3 results also suggest elranatamab has a manageable safety profile. The two-step-up priming dose regimen (12/32 mg) helped mitigate the rate and severity of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) among the 119 patients in cohort A who were treated with this priming regimen. All cases of CRS were grade 1 or 2 and the majority occurred after the first (43% of patients) or second (24% of patients) dose, with only 6% of patients experiencing CRS after the third dose and fewer than 1% experiencing CRS after the fourth dose. Observed cases of ICANS (3%) were neither common nor severe, with only ICANS grade 1/2 occurring. No fatal neurotoxicity events were observed.
Elranatamab is designed to bind to BCMA and CD3 receptors found on the surface of T cells, bridging them together and activating the T cells to kill the myeloma cells.
Source: Pfizer press release, February 2023