EHA2021: Targeting BCMA in Early-Phase Study in Resistant Myeloma
Posted: Thursday, June 24, 2021
Elranatamab, a monoclonal antibody targeting B-cell maturation antigen (BCMA), was reported to have an acceptable safety profile and a wide therapeutic index when treating patients with relapsed or refractory multiple myeloma. Caitlin Costello, MD, of the University of California San Diego, presented this phase I study results on behalf of her colleagues at the European Hematology Association Virtual Congress (EHA2021; Abstract S192).
“These results demonstrate the safety and efficacy of elranatamab in this relapsed/refractory population, confirm the feasibility and potential of BCMA-directed immunotherapy for malignant plasma cell disorders, and support ongoing development of elranatamab for patients with multiple myeloma,” concluded the authors.
A total of 30 patients with multiple myeloma who had relapsed or became refractory to prior treatment were included in the study. Patients received single-agent elranatamab subcutaneously at doses of 80 (n = 6), 130 (n = 4), 215 (n = 4), 360 (n = 4), 600 (n = 6), and 1,000 (n = 6) μg/kg every week.
The overall response rate for patients receiving doses higher than 215 μg/kg was 75% (n = 15/20), including 6 patients with a partial response, 3 with a very good partial response, 1 with a complete response, and 5 with a stringent complete response. It took a median of 22 days for patients to achieve a response. Of note, three of the four patients who had received previous BCMA-directed therapy achieved a response.
The most common treatment-emergent any-grade adverse events were lymphopenia (80%), cytokine-release syndrome (73%), anemia (57%), injection-site reaction (53%), thrombocytopenia (53%), and neutropenia (40%). Cytokine-release syndrome typically occurred with the first dose of elranatamab, and T-cell proliferation increased in the peripheral blood. No patients experienced dose-limiting toxicities, the investigators reported. The recommended phase II dose based on these findings is 1,000 μg/kg weekly.
Disclosure: For full disclosures of the study authors, visit library.ehaweb.org.