Regeneron announces data from Phase 2 trial of linvoseltamab

Regeneron Pharmaceuticals announced initial data from a pivotal Phase 2 expansion cohort evaluating investigational linvoseltamab at the 200 mg dose recommended for further development in patients with heavily pre-treated, relapsed/refractory multiple myeloma. The results were part of a broader presentation of new and updated data from a Phase 1/2 trial and were shared at the 64th American Society of Hematology Annual Meeting and Exposition in New Orleans, LA. Linvoseltamab is an investigational bispecific antibody designed to bridge B-cell maturation antigen on multiple myeloma cells with CD3-expressing T cells to facilitate local T-cell activation and cancer-cell killing. As presented at ASH, out of 252 patients treated in the Phase 1/2 trial, 81% of patients were triple-refractory to existing therapeutic options, including an immunomodulatory drug, a proteasome inhibitor and an anti-CD38 antibody. Additionally, 37% had bone marrow plasma cells greater than or equal to50%, and the median soluble BCMA was 0.43 mg/L, representing a patient population with a higher disease burden than those enrolled in similar trials. Of the 87 patients in the 200 mg cohort, 58 were evaluated for efficacy. With a median follow-up of 3 months efficacy results were as follows: 64% objective response rate, with 45% achieving a very good partial response or better, as determined by an independent review committee. Based on earlier results, responses may increase with longer follow-up. Median time to response was less than1 month. 79% probability of maintaining a response at 6 months, per Kaplan-Meier estimates. Among the 87 patients treated in the 200 mg cohort assessed for safety, adverse events occurred in 95% of patients, with 66% being greater than or equal toGrade 3. The most common AEs occurring in greater than or equal to20% of patients were cytokine release syndrome, fatigue, anemia, diarrhea, cough, headache and neutropenia. Discontinuations due to an AE occurred in 6% of patients. When CRS occurred, in 32 out of 87 patients, 23 of those patients experienced Grade 1, 8 experienced Grade 2, there was 1 transient Grade 3 case, and none were greater than or equal toGrade 4. Among the overall patient population across different dose levels, the median time to first CRS onset was 11 hours and all cases resolved, with a median time to resolution of 15 hours. Deaths due to AEs in the overall population were reported in 14 patients, including sepsis/bacterial infection, COVID-19 or other causes. None of the deaths were considered related to treatment per the treating physician.