Nektar Therapeutics (NASDAQ: NKTR) reports Baxter International Inc. today announced positive results from its Phase 3 pivotal clinical trial of BAX 855, an investigational, extended half-life recombinant factor VIII (rFVIII) treatment for hemophilia A based on ADVATE [Antihemophilic Factor (Recombinant)], which met its primary endpoint in reducing annualized bleed rates (ABR) in the prophylaxis arm compared to the on-demand arm.
Top-line results from the prospective, global, multi-center Phase 3 study demonstrated that BAX 855 met its primary endpoint in the control and prevention of bleeding, routine prophylaxis and perioperative management for patients who were 12 years or older. Patients in a twice-weekly prophylaxis arm experienced a 95 percent reduction in median ABR as compared to those in the on-demand arm (1.9 vs. 41.5, respectively). BAX 855 was also effective in treating bleeding episodes, 96 percent of which were controlled with one or two infusions. The half-life of BAX 855 was 1.4 - 1.5 times that of ADVATE, 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 (three patients) product-related adverse event was headache.
"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, M.D., 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."
The multi-center, open-label study evaluated BAX 855 among 138 adolescent and adult patients with previously-treated hemophilia A. Patients received treatment twice weekly (45 IU/kg) or on-demand, and were followed for six months. The primary objective of the study was the reduction in ABR during the treatment period compared to on-demand treatment. The study also evaluated the safety and immunogenicity of the compound when administered on either prophylaxis or on-demand treatment regimens.
Baxter expects to submit a Biologics License Application (BLA) for BAX 855 to the U.S. Food and Drug Administration (FDA) before the end of 2014 and will present additional data in the coming months. In addition to an ongoing continuation study for patients who have completed the pivotal trial, the company is initiating a Phase 3, prospective, open-label, multi-center study to evaluate the safety and efficacy of BAX 855 among 60 previously treated patients under the age of 12 with severe hemophilia A. Consistent with guidelines published by the European Medicines Agency (EMA) that require a study in children less than 12 years of age prior to filing, Baxter expects to file a Marketing Authorization Application with the EMA upon the completion of the pediatric study.
BAX 855 is based on ADVATE, a full-length FVIII molecule with more than 10 years of real-world experience. Through a collaboration with Nektar Therapeutics (NASDAQ: NKTR), BAX 855 leverages proprietary PEGylation technology designed to extend the duration of activity of proteins in the body. This proprietary technology has been used for over 10 years in a number of approved medicines that treat chronic or serious conditions.
Nektar Therapeutics; Baxter International Inc.