On March 28, 2025, the U.S. Food and Drug Administration (FDA) approved Qfitlia (fitusiran) for routine prophylaxis in adult and pediatric patients, aged 12 and older, with hemophilia A or B. This treatment is applicable to those with or without factor inhibitors, marking a significant step in managing hemophilia.
"Today’s approval of Qfitlia is significant for patients with hemophilia because it can be administered less frequently than other existing options," stated Tanya Wroblewski, M.D., deputy director of the Division of Non-Malignant Hematology in the FDA’s Center for Drug Evaluation and Research. "This new treatment option highlights our continued efforts to improve the lives of patients with hemophilia."
Hemophilia A and B are genetic disorders characterized by the dysfunction or deficiency of coagulation factor VIII (FVIII) or IX (FIX). These disorders impair proper blood clotting, leading to extended bleeding after injury or surgery and potentially life-threatening spontaneous bleeding episodes.
Qfitlia, unlike traditional treatments, does not replace the missing clotting factor but decreases the levels of a protein called antithrombin, resulting in increased thrombin, necessary for clotting. Administered subcutaneously, Qfitlia is injected every two months with dosage adjustments based on the FDA-approved INNOVANCE Antithrombin diagnostic test by Siemens Healthcare Diagnostics GmbH.
In clinical trials with 177 male patients, Qfitlia demonstrated significant efficacy. With an antithrombin-based dosing, participants with inhibitors experienced a 73% reduction in annualized bleeding rate, while those without inhibitors saw a 71% reduction, compared to their on-demand treatments.
Qfitlia carries a boxed warning regarding risks of thrombotic events and gallbladder disease, among other warnings, including liver toxicity. Common side effects include viral and bacterial infections as well as cold-like symptoms.
The FDA has recognized Qfitlia with Orphan Drug and Fast Track designations, approving it for use by Sanofi.
