Real-world clinical experience of extended half-life recombinant factor VIII Fc fusion protein (rFVIIIFc) in comparison to conventional factor products in patients with severe hemophilia A

Introduction: The recombinant factor FVIII Fc fusion protein (rFVIIIFc) is a first-in-class extended half-life FVIII product to treat patients with hemophilia A. The safety, efficacy and prolonged half-life of rFVIIIFc was demonstrated in the phase 3 studies A-LONG, Kids A-LONG and the extension study ASPIRE. Despite robust efficacy and safety data of rFVIIIFc therapy from clinical trials, evidence on the effectiveness of rFVIIIFc use in real-world remains scarce. Our analysis aimed at investigating the effectiveness of prophylactic rFVIIIFc treatment in routine clinical use in Germany. Material and Methods: Twenty-seven patients with severe hemophilia A, who switched from prophylaxis with conventional recombinant factor VIII (rFVIII) products to rFVIIIFc, were included. Annualized bleeding rates, factor consumption, number of injections and adherence to prophylaxis were compared. The retrospective period prior switching to rFVIIIFc was three years, while the mean follow-up period after switching to rFVIIIFc was 24.9 months. Results: Switching to rFVIIIFc led to a 33.7% reduction in mean annualized number of injections and a 18.3% reduction in mean annualized factor consumption while maintaining low bleeding rates. The mean annualized bleeding rate (ABR) was 2.5 and 1.7 for rFVIII and rFVIIIFc, respectively. The adherence improved from 87% to 94%. During the follow-up period eleven surgeries were performed; all with a hemostatic response rated as excellent. No FVIII inhibitor formation after switching to rFVIIIFc has been detected. Conclusion: Real-world treatment with rFVIIIFc was associated with substantial reductions in consumption and injection frequenies while maintaining low bleeding rates supporting safety and efficacy data from clinical trials.