Baxter International, Inc. recently announced positive results from its Phase 3 clinical trial of BAX 855, an experimental extended half-life recombinant factor VIII (rFVIII) therapy for the treatment of hemophilia A. The multicenter, international trial included 138 adolescents and adults with severe hemophilia A, who had been previously treated.

Patients were placed in two groups: one received twice weekly prophylactic treatment and the other treated on-demand. Both groups  were monitored for six months. The primary objective of the study was a reduction in annualized bleed rates (ABR) during the treatment period compared to on-demand treatment. Results demonstrated that BAX 855 met its primary endpoint in the control and prevention of bleeding, routine prophylaxis for patients who were 12 years or older. Patients in the prophylaxis arm experienced a 95% reduction in median ABR, compared to those in the on-demand arm (1.9 vs. 41.5, respectively). BAX 855 was also effective in treating bleeding episodes, 96% of which were controlled with one or two infusions.

BAX 855 uses Nektar Therapeutic’s pegylation technology to extend the duration of the clotting protein’s activity in the body. The half-life of BAX 855 was 1.4-1.5 times that of Baxter’s other rFVIII therapy ADVATE, which was consistent with the findings from the Phase 1 study. No patients developed inhibitors to BAX 855 and no treatment-related serious adverse events, including hypersensitivity, were reported. The most common product-related adverse event was a headache, experienced by three subjects.

“The positive results of the BAX 855 study reflect our ongoing, long-term commitment to drive innovation and expand treatment options for patients with hemophilia,” said John Orloff, MD, vice president and global head of research and development for Baxter BioScience. “We look forward to advancing the BAX 855 program to U.S. regulatory submission by the end of this year.”

Source: Baxter press release dated August 21, 2014