Long Term Safety and Efficacy of Recombinant Factor IX Fc Fusion Protein (rFIXFc) Prophylaxis in Children with Hemophilia B: Interim Results of the B-Yond Extension Study

Abstract

Introduction: The phase 3 Kids B-LONG study (NCT01440946) demonstrated the safety, efficacy, and pharmacokinetics of prophylactic recombinant factor IX Fc fusion protein (rFIXFc) for the prevention and treatment of bleeding episodes in children with severe hemophilia B. The ongoing rFIXFc extension study B-YOND (NCT01425723) is evaluating long-term safety and efficacy of rFIXFc in children and adults with hemophilia B. The safety and efficacy data for pediatric subjects from the second B-YOND interim data cut (11 Sep 2015) are reported here. Methods: The Kids B-LONG study enrolled males aged Results: At the time of the second B-YOND interim data cut, 27 subjects had completed Kids B-LONG and enrolled in B-YOND ( Conclusion: These data confirm the long-term safety of rFIXFc with maintenance of low ABRs and extended-interval prophylaxis in children with hemophilia B. This research was funded by Biogen and Sobi. Biogen and Sobi reviewed and provided feedback on the abstract. The authors had full editorial control of the abstract and provided their final approval of all content. Disclosures Ducore:Octapharama: Membership on an entity9s Board of Directors or advisory committees; Baxalta (Shire): Membership on an entity9s Board of Directors or advisory committees; LFB: Membership on an entity9s Board of Directors or advisory committees; Bayer: Membership on an entity9s Board of Directors or advisory committees; Pfizer: Membership on an entity9s Board of Directors or advisory committees; CSL Behring: Membership on an entity9s Board of Directors or advisory committees; Biogen: Membership on an entity9s Board of Directors or advisory committees. Fischer:Baxter: Consultancy, Research Funding, Speakers Bureau; NovoNordisk: Consultancy, Research Funding, Speakers Bureau; Octapharma: Speakers Bureau; Biogen: Consultancy; Biotest: Consultancy, Speakers Bureau; Baxalta/Baxter: Consultancy, Research Funding, Speakers Bureau; Wyeth: Research Funding; Pfizer: Consultancy, Research Funding, Speakers Bureau; CSL Behring: Consultancy, Speakers Bureau; Bayer: Consultancy, Research Funding, Speakers Bureau; Freeline: Consultancy. Kulkarni:Kedrion: Membership on an entity9s Board of Directors or advisory committees; BPL: Membership on an entity9s Board of Directors or advisory committees; Biogen: Research Funding, Speakers Bureau; Pfizer: Membership on an entity9s Board of Directors or advisory committees; Novo Nordisk: Membership on an entity9s Board of Directors or advisory committees, Research Funding; Bayer: Membership on an entity9s Board of Directors or advisory committees, Research Funding; Baxter: Membership on an entity9s Board of Directors or advisory committees, Research Funding. Nolan:Sobi: Research Funding; Biogen: Research Funding. Perry:Biogen: Consultancy, Honoraria; Novo Nordisk: Consultancy, Membership on an entity9s Board of Directors or advisory committees. Yuan:Biogen: Employment, Equity Ownership. Ramirez-Santiago:Biogen: Employment, Equity Ownership. Ferrante:Sobi: Employment. Lethagen:Sobi: Employment.