The phase 2 MagnetisMM-3 trial that will test an investigational B-cell maturation antigen (BCMA) CD3-targeted bispecific antibody in patients with relapsed or refractory multiple myeloma has begun, according to a Pfizer press release.
The goal of the trial (ClinicalTrials.gov Identifier: NCT04649359) is to determine the safety and efficacy of subcutaneous elranatamab (PF-06863135) for the treatment of patients with relapsed or refractory multiple myeloma. Binding of elranatamab to CD3-expressing T-cells and BCMA-expressing multiple myeloma cells causes targeted T-cell-mediated cytotoxicity.
The study organizers estimate an enrollment of 150 participants divided into 2 cohorts: one cohort with and one without prior treatment with a BCMA-directed antibody drug conjugate or CAR T-cell therapy. Participants must be refractory to treatment with at least one proteasome inhibitor, one immunomodulatory drug, and one anti-CD38 antibody. The primary outcome measure of the study is objective response rate, which will be assessed approximately every 4 weeks for up to approximately 2 years.
Pfizer presented data from a phase 1 trial of elranatamab at the 62nd American Society of Hematology (ASH) Annual Meeting and Exposition, held virtually from December 4th through December 7th, 2020. Trial data showed that elranatamab had a manageable safety profile with high response rates in patients with relapsed or refractory multiple myeloma. Three patients on the trial had disease that relapsed on or progressed after prior BCMA-targeted therapy.
At the highest dose level given in the phase 1 trial, 83% of patients achieved a clinical response.
“Second and later relapses are unfortunately all too common in multiple myeloma and can be devastating to patients as remissions tend to be shorter and the disease may be more aggressive,” Alexander M. Lesokhin, MD, lead investigator and hematologic oncologist at Memorial Sloan Kettering Cancer Center, in New York City, said in a Pfizer press release. “Targeting BCMA is a promising area of innovation in multiple myeloma.”
The US Food and Drug Administration has granted elranatamab Fast Track Designation.