In the phase 3 Study to Evaluate the Efficacy and Safety of PF-07055480 / Giroctocogene Fitelparvovec Gene Therapy in Moderately Severe to Severe Hemophilia A Adults (AFFINE) study on giroctocogene fitelparvovec, deep vein thrombosis was observed in a patient with high FVIII levels after dosing. This evidence concerns the gene F8 and hemophilia A.