Pfizer Reports Phase 3 AFFINE Results for Gene Therapy in Hemophilia A

Pfizer today announced results from the Phase 3 AFFINE trial evaluating giroctocogene fitelparvovec, an adeno-associated virus (AAV) gene therapy, in adults with moderate-to-severe hemophilia A. The trial met its primary endpoint, demonstrating a statistically significant reduction in the annualized bleeding rate compared to prior prophylaxis. At 15 months, 84% of participants had no treated bleeds. Giroctocogene fitelparvovec delivers a functional copy of the factor VIII gene to liver cells, enabling endogenous factor VIII production. These results support gene therapy as a potential one-time treatment for hemophilia A.