This Phase III clinical study will assess the impact of BMN 270 (compared to FVIII prophylaxis) on the number of bleeding episodes irrespective of exogenous FVIII replacement treatment in the efficacy evaluation period (EEP) (from Week 5 post-BMN 270 infusion (Study Day 33) or the end of FVIII prophylaxis plus the washout period (3 days for products of standard half-life or plasma-derived and 5 days for products of extended half-life), whichever is later, to last visit by the data cut-off for the 2-year analysis, hereafter referred to as "Post FVIII Prophylaxis to Last Visit"). The study will also assess the impact of BMN 270 (compared to FVIII prophylaxis) on: the number of bleeding episodes requiring exogenous FVIII treatment in "Post FVIII Prophylaxis to Last Visit", FVIII activity as measured by chromogenic sustrate assay at Week 104 following intravenous infusion of BMN 270, usage of exogenous FVIII replacement therapy in "Post FVIII Prophylaxis to Last Visit", health-related quality of life patient-reported outcomes at week 104 following intravenous infusion of BMN 270. The study will also evaluate the safety of the BMN 270.
A Phase 3 Open-Label, Single-Arm Study To Evaluate The Efficacy and Safety of BMN 270, an Adeno-Associated Virus Vector-Mediated Gene Transfer of Human Factor VIII in Hemophilia A Patients With Residual FVIII Levels ≤ 1 IU/dL Receiving Prophylactic FVIII Infusions