US-based Baxter International has completed patient enrolment in its Phase III clinical trial of BAX 855, an investigational extended half-life, recombinant factor VIII (rFVIII) treatment for haemophilia A.
The trial is aimed at evaluating the efficacy of BAX 855 in reducing annualised bleed rates (ABR) in both prophylaxis and on-demand treatment schedules, and will also assess the safety and pharmacokinetic profile of the compound.
Baxter BioScience business vice-president of global research and development Anders Ullman said the BAX 855 development programme is a priority for the company as they assess the potential to provide an efficacious and safe treatment with an extended half-life for patients with hemophilia.
"We are focused first and foremost on strategies to address optimal efficacy and minimise patients' bleeding episodes, while at the same time delivering on the convenience of less frequent dosing for this population with severe disease," Ullman said.
Around 146 adult patients with previously-treated severe haemophilia A are being treated with BAX 855 in the Phase II/III multi-centre, open-label study known as PROLONG-ATE.
In PROLONG-ATE patients will be given treatment twice weekly (45 IU/kg) and are followed for six months.
The primary endpoint of the trial is the annualised bleed rate (ABR) during the treatment period. It is also assessing the safety and immunogenicity of the compound when administered on either prophylaxis and on-demand treatment regimens, while other outcome measures include number of infusions needed to treat bleeding episodes, time intervals between these episodes, pharmacokinetics and patient reported outcomes.
As part of the ongoing trial, no inhibitors or safety issues have been reported in the study to date.
Baxter intends to complete the trial and submit a regulatory approval late in 2014, based upon the study results.
The company is also starting a continuation study for all patients who complete the Phase II/III trial, and expects to commence a study of BAX 855 among paediatric patients in 2014.
According to the company, the treatment protocol is based on the results of a Phase I trial of BAX 855, evaluating its safety, tolerability and pharmacokinetics.
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 with ADVATE in the Phase I study.
In addition, 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.
BAX 855 was designed based on the full-length ADVATE [antihaemophilic factor (recombinant) plasma/albumin-free method] molecule, was modified with PEGylation technology to extend its duration of activity in the body.
ADVATE is indicated for the control and prevention of bleeding episodes as well as for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adults and children (0-16 years) with haemophilia A.