Baxter's long-acting haemophilia A therapy BAX 855 meets main goal of Phase III study

Baxter announced top-line Phase III results Thursday demonstrating that its experimental haemophilia A therapy BAX 855, which is a longer-acting recombinant factor VIII product based on Advate (anti-haemophilic factor recombinant, plasma/albumin-free method, rFVIII), significantly reduced annualised bleeding rates when used as a preventative measure, versus on an as-needed basis. John Orloff, global head of R&D for Baxter BioScience, said the company intends to advance "the BAX 855 programme to US regulatory submission by the end of this year."

The study involved 138 adolescents and adults previously treated for haemophilia A who received infusions of BAX 855, either twice-weekly as prophylaxis or on-demand, and were followed for six months. In addition to the primary endpoint comparing annualised bleeding rates between the prophylactic and on-demand groups, the study also evaluated the safety and immunogenicity of the compound for both treatment strategies.

Results illustrated that the prophylaxis arm achieved a median annualised bleeding rate of 1.9, versus 41.5 in the on-demand group. The company also noted that BAX 855 effectively treated bleeding episodes, with 96 percent of such episodes controlled with one or two infusions. Meanwhile, Baxter noted that the therapy's half-life was 1.4- to 1.5-fold longer than that of Advate, consistent with early-stage study results. The company added that no patients developed inhibitors to BAX 855, nor had any reported treatment-related serious adverse effects, such as hypersensitivity. Additional data from the trial will be presented in the coming months.

Baxter indicated that besides an ongoing continuation study for patients who completed the pivotal trial, it is initiating a Phase III study of the therapy in 60 patients under 12 who have severe haemophilia A, with a European regulatory application planned following completion of the paediatric study. The drugmaker noted that BAX 855 features Nektar Therapeutics' proprietary PEGylation technology, which is designed to lengthen the duration of protein activity within the body.

In July, the drugmaker lifted the guidance for its haemophilia franchise, which generated 6-percent higher sales during the second quarter at $904 million.

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