Additional Relevant Details
In the 6e13 vg/kg cohort, the data showed continued and substantial reductions in bleeding requiring Factor VIII infusions with a 97% reduction in mean Annualized Bleed Rate (ABR), with no spontaneous bleeds and elimination of all bleeds in target joints in the second year. 71% and 86% of participants had zero bleeds requiring Factor VIII infusions in years 1 and 2 respectively compared to 14%, who had zero bleeds requiring Factor VIII infusions for a year at baseline. There was a 96% reduction in mean FVIII usage through week 104. Quality of life as measured by the six-domain Haemo-QoL-A instrument rapidly improved across all domains by up to 17.3 points in mean over baseline through the second year. This is well above the 5.2 point increase considered to be the minimal clinically important difference.The 4e13 vg/kg cohort also showed a substantial reduction in bleeding requiring Factor VIII infusions with a 92% reduction in ABR. 83% of participants had zero bleeds requiring Factor VIII infusions following treatment for a year compared to 17%, who had zero bleeds requiring Factor VIII infusions for a year at baseline. Mean Factor VIII usage decreased by 98%. Consistent with the reduction in ABR and FVIII usage, quality of life showed mean improvement by 3.8 to 6.3 points.For the 6e13 vg/kg cohort, mean Factor VIII activity levels from week 20 through 104 have been consistently within the normal or near normal range and no participant was above the upper limit of normal at week 104, expressed as a percentage of normal factor activity in blood. At 104 weeks post-infusion, mean Factor VIII activity level of the 6e13 vg/kg cohort is within the normal range at 59%, and the median is near normal at 46%. For the 4e13 vg/kg cohort, mean Factor VIII activity levels from week 20 through 52 have been consistently within the mild range, expressed as a percentage of normal factor activity in blood. At 52 weeks post-infusion, mean and median Factor VIII activity levels of the 4e13 vg/kg cohort are 32%.