Results from B-YOND Extension Study Reinforce Long-Term Clinical Profile of Alprolix for the Treatment of Hemophilia B

Biogen has announced new clinical data support the long-term safety and efficacy of Alprolix [Coagulation Factor IX (Recombinant), Fc Fusion Protein] in people with severe hemophilia B treated for up to 2 years. Participants in the Phase III, open-label extension study, B-YOND, maintained low bleeding rates with 1–2 week prophylaxis regimens, according to data from an interim analysis. Investigators presented these interim results for the first time at the 67th Annual Meeting for the National Hemophilia Foundation (NHF) in Dallas.

B-YOND is a multi-year study for people with severe hemophilia B who completed the Phase III pivotal B-LONG or Kids B-LONG studies. In this interim analysis, the median time on ALPROLIX during B-YOND was 27.6 months for adults and adolescents (n=93), and 47.7 weeks for children under age 12 (n=23). The study’s primary endpoint is inhibitor development, and no inhibitors have been reported to-date. There were three prophylactic dosing options for adult, adolescent, and pediatric participants in the B-YOND trial – weekly, individualized, and modified prophylaxis. An episodic treatment arm was also available for adult and adolescent patients.

“We believe B-YOND will play an important role in helping us understand this therapy’s clinical profile over the long term,” said Amy Shapiro, co-founder and medical director of the Indiana Hemophilia and Thrombosis Center. “Study participants receiving prophylactic treatment with intervals of 1–2 weeks between infusions continue to experience low bleeding rates during this ongoing extension study.”