RO7297089, a bispecific tetravalent antibody targeting BCMA and CD16a in patients with relapsed or refractory multiple myeloma, showed modest activity at doses up to 1080 mg and no dose-limiting toxicities in a first-in-humans Phase 1 trial reported at the American Society of Hematology Annual Meeting & Exposition in December.

Results were reported for 21 patients who were treated at five dose levels ranging from 60 mg to 1080 mg. Patients, whose median age was 63, had received a median of eight prior lines of therapy. Prior exposure to CAR-T cells, T-cell engaging bispecific antibodies, and therapies targeting BCMA was permitted.

Responses were evaluable in 18 patients. One patient in the 1080 mg cohort experienced a partial response based on International Myeloma Working Group criteria. Ten patients experienced stable disease at dose levels ranging from 60 mg to 1080 mg. One patient who started at 60 mg and escalated to 1080 mg had been on treatment with stable disease for 9.5 months as of the clinical cut-off date.

Reported adverse events of grade 3 or greater included anemia (9 patients) and decreased platelet count (5 patients). Disease progression was the most common reason for discontinuation of the study treatment (12 patients). Four patients died of disease progression during the adverse event follow-up period.

• Plesner T, Harrison SJ, Quach H, et al. A Phase I Study of RO7297089, a B Cell Maturation Antigen (BCMA)-CD16a Bispecific Antibody in Patients with Relapsed/Refractory Multiple Myeloma (RRMM). Abstract 2755. Presented at the 63rd American Society of Hematology Annual Meeting & Exposition, 2021 December 12.

Tags: transplantation, Cellular therapy, BiTEs, Research, Transplant, cell therapy, RRMM, Phase 1 trial, humans trial, antibody, BCMACD