Pegylated Recombinant Factor VIII Appears Safe and Efficacious as Prophylactic and On-Demand Hemophilia A Therapy

Baxalta’s BAX 855, a pegylated full-length recombinant factor VIII (rFVIII) based on the licensed rFVIII product Advate, was designed to increase half-life and potentially reduce the frequency of prophylactic infusions while maintaining hemostatic efficacy. This pivotal study assessed pharmacokinetic (PK) parameters of BAX 855, the annualized bleeding rate (ABR) with prophylaxis and on-demand treatment, and efficacy.

PK data from this pivotal study in previously treated patients with severe hemophilia A confirmed that the mean half-life and mean residence time of BAX 855 compared with Advate were 1.4- to 1.5-fold higher. Subjects in the twice-weekly prophylaxis arm experienced a 95 percent reduction in median ABR versus those assigned to the on-demand arm (1.9 versus 41.5, respectively). BAX 855 was efficacious for the treatment of bleeding episodes, with 95.9 percent of bleeding episodes controlled with one or two infusions, and 95.9 percent treatments having “excellent” or “good” efficacy ratings.

No FVIII inhibitory antibodies or safety signals were identified. The authors concluded that BAX 855 was safe and efficacious for on-demand treatment and prophylaxis administered twice weekly in patients with hemophilia A.