Posted: Thursday, November 2, 2023
Elranatamab—a humanized B-cell maturation antigen (BCMA)-CD3 bispecific antibody—continues to show potential as an effective, relatively safe agent for heavily pretreated patients with multiple myeloma, according to Alexander M. Lesokhin, MD, of Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York, and colleagues, in describing the results of their research in Nature Medicine. Specifically, they reported on the 123-patient cohort A of the ongoing phase II MagnetisMM-3 trial.
MagnetisMM-3 includes patients with relapsed or refractory disease who received subcutaneous elranatamab once weekly after two step-up priming doses. Then, after six cycles, persistent responders switched to once-every-2-weeks dosing. Cohort A comprises patients without prior BCMA-directed therapy.
In cohort A, 50 responders switched to biweekly dosing, and 40 (80%) improved or maintained their response for 6 or more months. The primary endpoint of confirmed objective response rate by blinded independent central review was met: 61% (75 of 123 patients), with 35% having a complete response or better.
With a median follow-up of 14.7 months, three secondary endpoints—median duration of response, progression-free survival, and overall survival—have not been reached, noted the team. “[The] 15-month rates were 71.5%, 50.9%, and 56.7%, respectively,” they added.
With biweekly dosing, grade 3 or 4 adverse events decreased from 58.6% to 46.6%, indicating this strategy may improve long-term safety without compromising efficacy. Common adverse events (any grade; grade 3 or 4) included infections (69.9%; 39.8%), cytokine-release syndrome (57.7%; 0%), anemia (48.8%; 37.4%), and neutropenia (48.8%; 48.8%).
Of note, elranatamab is “a readily accessible, off-the-shelf therapy, which provides an option for patients unable to access chimeric antigen receptor T-cell therapy,” the researchers pointed out. “These results support [its] continued development as monotherapy and its further investigation in combination with standard or new therapies.”
Disclosure: The study authors’ disclosure information can be found at nature.com.