Study to Evaluate the Efficacy and Safety of PF-07055480 / Giroctocogene Fitelparvovec Gene Therapy in Moderately Severe to Severe Hemophilia A Adults

C3731003 is a pivotal Phase 3 study to evaluate the clinical efficacy and safety of a single IV infusion of PF-07055480 / giroctocogene fitelparvovec (Recombinant AAV2/6 Human Factor VIII Gene Therapy) in adult male participants with moderately severe or severe hemophilia A (FVIII:C≤1%) for the study duration of 5 years. The study will enroll eligible participants who have been followed on routine prophylaxis with FVIII products in the Lead-In study C0371004.

Main inclusion Criteria * Males who have been followed on routine Factor VIII prophylaxis therapy during the lead-in study (C0371004) and have \> = 150 documented exposure days to a Factor VIII protein product * Moderately severe to severe hemophilia A (Factor VIII activity \< =1%) * Suspension of FVIII prophylaxis therapy post study drug infusion Main exclusion Criteria * Anti-AAV6 neutralizing antibodies * History of inhibitor to Factor VIII * Laboratory values at screening visit that are abnormal or outside acceptable study limits * Significant and/or unstable liver disease, biliary disease, significant liver fibrosis * Conditions associated with increased thromboembolic risk such as inherited or acquired thrombophilia, or a history of thrombotic events * Planned surgical procedure requiring Factor VIII surgical prophylactic factor treatment 12 months from screening visit * Active hepatitis B or C * Serological evidence of human immunodeficiency virus HIV-1 or HIV-2 with Cluster of Differentiation 4 positive (CD4+) cell count ≤200 mm3 and/or viral load \>20 copies/mL