Fitusiran: First Approval.

Haemophilia A and B are inherited bleeding disorders caused by mutations in clotting factors. Small interfering RNA therapies may be utilised to restore coagulation by preventing the synthesis of antithrombin. Fitusiran (QFITLIA™) is a small interfering RNA therapy that targets antithrombin, which is being developed by Sanofi for the prophylactic management of haemophilia A and B with or without inhibitors. Fitusiran has the potential to be administered less frequently than other prophylactic treatments for haemophilia. This article summarizes the milestones in the development of fitusiran leading to this first approval for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and paediatric patients aged 12 years and older with haemophilia A or B with or without factor VIII or IX inhibitors.