Hereditary/Acquired Bleeding Disorders

This international, multicenter, randomized open-label study was presented as a late-breaking abstract at the 63rd Annual Meeting of the American Society of Hematology (ASH). Investigators evaluated fitusiran efficacy and safety in males 12 years of age and older with severe hemophilia A or B without inhibitors, previously receiving on-demand (OD) treatment. Patients were randomized 2:1 to receive prophylaxis with 80 mg fitusiran subcutaneously or OD factor concentrates for treatment of bleeding episodes over a 9-month treatment period. The primary endpoint was annualized bleeding rate (ABR) in the efficacy period (Day 29 following the first dose of fitusiran up to Day 246). Secondary endpoints included annualized spontaneous bleeding rate (AsBR) and annualized joint bleeding rate (AJBR) in the efficacy period and health-related quality of life (HRQoL) improvement. A total of 80 patients were randomized to fitusiran (62 with hemophilia A, 18 with hemophilia B) and 40 (31 with hemophilia A, 9 with hemophilia B) were randomized to OD treatment. At ASH, the investigators reported that all key primary and secondary endpoints were met and serious treatment-related adverse events with fitusiran were consistent with previously identified risks. "Once-monthly 80 mg SC fitusiran prophylaxis," they concluded, "demonstrated a significant reduction in ABR, AsBR and AJBR (all ~90%) in people with severe hemophilia A or B without inhibitors compared with OD treatment. This reduction in bleeding was associated with a meaningful improvement in HRQoL."