HYMPAVZI: Once-weekly hemophilia treatment cuts bleeds by 93% in patients with inhibitors
SHERIDAN, WYOMING – December 10, 2025 – For many people living with hemophilia, treatment is already demanding—regular infusions, constant planning, and the worry of a bleed that can disrupt everything. But for those who develop “inhibitors,” standard therapies may stop working, turning daily life into a much more dangerous balancing act. New Phase 3 data from Pfizer now suggest that the once-weekly treatment HYMPAVZI® (marstacimab) could offer these patients a very different outlook.
When hemophilia treatments suddenly stop working
Hemophilia A and B are rare genetic bleeding disorders where the blood can’t clot properly. For decades, the usual approach has been factor replacement therapy, giving patients the clotting factor their bodies are missing.