Prophylaxis with rFIXFc Reduces the Frequency and Delays Time to First Spontaneous Bleed Event in Previously Untreated Patients with Hemophilia B: A Post Hoc Analysis of the PUPs B-LONG Trial

Introduction: Hemophilia B is a bleeding disorder characterized by coagulation factor IX (FIX) deficiency and is associated with symptoms of prolonged bleeding upon trauma and spontaneous bleed events. The current standard of care for people with hemophilia B is prophylactic FIX replacement therapy for the prevention of bleed events (Goodeve et al. J Thromb Haemost. 2015; Saini et al. Haemophilia. 2015; Castaman. Expert Rev Hematol. 2018). The aim of this study is to present a descriptive post hoc analysis of spontaneous bleed events in the context of treatment regimen (eg, prophylaxis [PPX] versus on-demand [OD]) in previously untreated participants (PUPs) with hemophilia B treated with extended half-life recombinant factor IX Fc fusion protein (rFIXFc, Alprolix) from the PUPs B-LONG study.