Baxter International Inc. has completed enrollment in its phase III clinical trial of BAX 855, an investigational extended half-life, recombinant factor VIII (rFVIII) treatment for haemophilia A. The ongoing trial is aimed at assessing the efficacy of the compound in reducing annualized bleed rates (ABR) in both prophylaxis and on-demand treatment schedules, and will also evaluate its safety and pharmacokinetic profile.

BAX 855 was designed based on the full-length ADVATE [Antihemophilic Factor (Recombinant) Plasma/Albumin-Free Method] molecule, a product with 10 years of real-world experience. The BAX 855 molecule was modified with PEGylation technology designed to extend its duration of activity in the body.

"The BAX 855 development programme is a priority for Baxter as we evaluate the potential to provide an efficacious and safe treatment with an extended half-life for patients with hemophilia," said Anders Ullman, MD, Ph.D., vice president of global research and development in Baxter's BioScience business. "We are focused first and foremost on strategies to address optimal efficacy and minimize patients' bleeding episodes, while at the same time delivering on the convenience of less frequent dosing for this population with severe disease."

The phase II/III multi-centre, open-label study called PROLONG-ATE is evaluating BAX 855 among 146 adult patients with previously-treated severe haemophilia A. Patients participating in PROLONG-ATE receive treatment twice weekly (45 IU/kg) and are followed for six months. The primary endpoint of the study is the annualized bleed rate (ABR) during the treatment period. The study is also evaluating the safety and immunogenicity of the compound when administered on either prophylaxis and on-demand treatment regimens. Other outcome measures include number of infusions needed to treat bleeding episodes, time intervals between these episodes, pharmacokinetics and patient reported outcomes. To date, no inhibitors or safety issues have been reported in the study.

Based upon the results of the study, the company expects to complete the trial and file for regulatory approval late in 2014. Baxter is also initiating a continuation study for all patients who complete the pivotal phase II/III study, and expects to initiate a study of BAX 855 among pediatric patients in 2014.

The treatment protocol is based on the results of a phase I trial of BAX 855, assessing its safety, tolerability and pharmacokinetics. That trial found that the half-life (measuring the duration of activity of the drug in the body) of the investigational compound was approximately 1.5-fold higher compared to ADVATE. An extended half-life was achieved in all patients in the study using BAX 855, no patients developed inhibitors to either the base molecule, BAX 855 or to PEG, and no patients had allergic reactions. No treatment-related or serious adverse events were reported, and no patients withdrew from the study due to adverse events.

BAX 855 is built from the same native FVIII protein used in the production of ADVATE, and employs proprietary PEGylation technology from Nektar Therapeutics designed to extend the duration of activity of proteins. PEGylation technology has been widely used in various approved treatments.

ADVATE [Antihemophilic Factor (Recombinant) Plasma/Albumin-Free Method] is indicated for the control and prevention of bleeding episodes in adults and children (0-16 years) with haemophilia A. ADVATE is also indicated for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adults and children (0-16 years) with haemophilia A. ADVATE is not indicated for the treatment of von Willebrand disease.

ADVATE has a demonstrated efficacy profile and a low rate of inhibitor development. ADVATE is a full-length (derived from the complete FVIII gene) recombinant FVIII product that is processed without any blood-based additives. Because no blood-derived components are added at any stage of the manufacturing process, the potential risk of transmitting pathogens that may be carried in blood-based additives is eliminated. There have been no confirmed reports of transmission of HIV, HBV or HCV with rFVIII treatments.

ADVATE is approved in 60 countries worldwide including the United States, Canada, 27 countries in the European Union, Argentina, Australia, Brazil, Chile, China, Colombia, Croatia, Ecuador, Hong Kong, Iceland, Iraq, Japan, Kuwait, Macau, Malaysia, Mexico, New Zealand, Norway, Panama, Puerto Rico, Serbia, Singapore, South Korea, Suriname, Switzerland, Taiwan, Tunisia, Turkey, Ukraine, Uruguay, and Venezuela.

Baxter International Inc., through its subsidiaries, develops, manufactures and markets products that save and sustain the lives of people with hemophilia, immune disorders, cancer, infectious diseases, kidney disease, trauma and other chronic and acute medical conditions.