Pfizer and Sangamo’s Gene Therapy Shows Superiority Over Prophylaxis in Hemophilia A Study

1. Positive Results: Pfizer announced positive topline results from the Phase 3 AFFINE study of giroctocogene fitelparvovec, an investigational gene therapy for hemophilia A, demonstrating superiority over routine Factor VIII (FVIII) replacement prophylaxis treatment.
2. Primary Endpoint: The study met its primary endpoint of non-inferiority and superiority in total annualized bleeding rate (ABR) from Week 12 through at least 15 months post-infusion compared to prophylaxis.
3. Statistical Significance: The therapy showed a statistically significant reduction in mean total ABR compared to the pre-infusion period (1.24 vs 4.73; one-sided p-value=0.0040).
4. Key Secondary Endpoints: The study also met key secondary endpoints, including 84% of participants maintaining FVIII activity >5% at 15 months post-infusion (one-sided p-value=0.0086) and a statistically significant reduction in treated ABR.
5. Gene Therapy Potential: The results demonstrate the transformative potential of giroctocogene fitelparvovec as a one-time gene therapy for people with hemophilia A, providing superior bleed protection and relieving the treatment burden.
6. Collaboration: Giroctocogene fitelparvovec is codeveloped by Sangamo Therapeutics and licensed to Pfizer.
7. Hemophilia A: Hemophilia A is an inherited, rare bleeding disorder that affects approximately 25 in every 100,000 male births worldwide, with 55-75% of males having a moderate to severe form of the disease.