FDA Expands Approval of Pfizer’s HYMPAVZI for Additional Hemophilia A and B Patient Groups
Tuesday, June 09, 2026
Pfizer has received approval from the U.S. Food and Drug Administration (FDA) for an expanded indication of HYMPAVZI® (marstacimab-hncq), extending its use to patients aged 12 years and older with hemophilia A or B who have inhibitors, as well as children aged 6 to 11 years with or without inhibitors.
HYMPAVZI is now approved in the United States as a routine prophylactic treatment to prevent or reduce bleeding episodes in adults and children aged six years and older with hemophilia A or B, regardless of inhibitor status. The treatment is administered once weekly by subcutaneous injection and does not require routine treatment-related laboratory monitoring.
Hemophilia is usually diagnosed during childhood and affects more than 800,000 people worldwide. The condition impairs the blood’s ability to clot properly, increasing the risk of bleeding episodes that can lead to joint damage over time. Patients who develop inhibitors to factor replacement therapies often face additional treatment challenges, as these antibodies can reduce the effectiveness of standard therapies.
The expanded approval was supported by data from the Phase 3 BASIS trial, which evaluated HYMPAVZI in adolescents and adults aged 12 years and older with hemophilia A or B and inhibitors. The study showed a 93% reduction in mean treated annualised bleeding rate (ABR) compared with on-demand intravenous treatment using bypassing agents.
Additional support came from interim results of the Phase 3 BASIS KIDS trial involving children aged 6 to 17 years with hemophilia A or B, with or without inhibitors. The findings showed low treated bleeding rates in children receiving HYMPAVZI, including those with inhibitors and those previously treated with routine prophylaxis or on-demand therapies.
The most commonly reported adverse reactions in adults and children aged six years and older included injection-site reactions, headache, fever, joint pain, diarrhoea, itching and rash. The prescribing information also includes warnings regarding thromboembolic events, hypersensitivity reactions, embryofetal toxicity and certain laboratory abnormalities.
The application was reviewed under the FDA’s Priority Review programme, which is intended for medicines that may offer significant improvements over existing treatment options. HYMPAVZI also received Breakthrough Therapy Designation for routine prophylaxis in younger paediatric patients with hemophilia B, with and without inhibitors.
The approval expands treatment options for patients with hemophilia and supports Pfizer’s ongoing efforts to develop therapies that improve disease management and quality of life.
Source: businesswire.com/
