Regeneron Pharmaceuticals Inc. (NASDAQ: REGN) announced results from its Phase 1/2 LINKER-AL2 trial evaluating linvoseltamab in patients with second-line-plus systemic amyloid light chain amyloidosis, according to a company statement.

The study enrolled 20 patients who received linvoseltamab at doses of 80 mg or 240 mg subcutaneously. All patients achieved hematologic responses, with 100% of patients in the higher-dose group achieving complete response. In the lower-dose group, 71% achieved complete response and 100% achieved very good partial response or better.

The median time to hematologic complete response was 47 days, with involved free light chain normalization occurring by day 15 across all doses. Among patients with organ involvement, 73% showed improved renal function and 50% demonstrated improved cardiac function.

All patients experienced at least one treatment-emergent adverse event, with 65% experiencing grade 3 or higher events. The most common side effects were cytokine release syndrome in 50% of patients, neutropenia in 40%, and infusion-related reactions in 35%. Infections occurred in 85% of patients, with 25% experiencing grade 3 or higher infections.

Two deaths occurred during the study: one from sudden death in a patient with cardiac amyloidosis who had achieved complete response, and one from ventricular fibrillation within 24 hours of coronary artery stent placement, which investigators assessed as unrelated to treatment.

Systemic AL amyloidosis affects approximately 4,400 patients annually in the United States. The condition has no approved therapies for patients whose initial treatment fails. Linvoseltamab is currently approved for treating certain adults with relapsed or refractory multiple myeloma.

The Phase 2 portion of the trial with registrational intent continues. Results will be presented at the American Society of Clinical Oncology Annual Meeting.