Treatment of bleeding episodes with recombinant factor VIII Fc fusion protein in A‐LONG study subjects with severe haemophilia A

Introduction The Phase 3 A‐ LONG study demonstrated the safety and efficacy of rFVIIIF c for the control and prevention of bleeding episodes in severe haemophilia A. Aim To describe the treatment of bleeding episodes with rFVIIIF c in the A‐ LONG study. Methods A‐ LONG subjects (<1 IU dL −1 endogenous FVIII ) were treated with individualized prophylaxis (Arm 1), weekly prophylaxis (Arm 2) or episodic treatment (Arm 3). Information recorded for each bleeding episode included type, location and dose to treat the episode. Results During A‐ LONG , 757 bleeding episodes occurred during the efficacy period; the majority [456 (60%)] occurred in Arm 3 (episodic treatment). Of 93 subjects in the prophylaxis arms who entered the study with target joints, 43 (60%) in Arm 1 and 11 (52%) in Arm 2 did not experience a target joint bleed. Overall, 98% of bleeding episodes (and 98% of bleeds involving a target joint) resolved with one or two infusions; the median dose per infusion to treat a bleed was 27 IU kg −1 (27 IU kg −1 for target joints). Using population pharmacokinetic simulations, FVIII activity levels were predicted to be below the upper limit of normal (150 IU dL −1 ) in most patients in the event that rFVIIIF c is used to treat a bleeding episode in close proximity to a prophylactic dose. Conclusions These findings demonstrate the efficacy of rFVIIIF c for the treatment of acute bleeding episodes in subjects with severe haemophilia A, regardless of treatment regimen.