DEERFIELD (dpa-AFX) - Baxter International Inc. (BAX) presented additional data from the Phase III clinical trial of BAX 111, the first highly-purified recombinant von Willebrand Factor (rVWF) in clinical development as a treatment for patients with von Willebrand disease, the most common type of inherited bleeding disorder.
The trial met its primary efficacy endpoint defined by the number of patients who achieved treatment success for control of bleeding episodes.
All patients treated in the full analysis set (N=22) experienced a 100 percent treatment success rating based on a 4-point efficacy rating scale, comparing estimated number of infusions needed to treat the bleeding episodes to the actual number of infusions administered. Efficacy for all treated bleeds (N=192) was rated excellent (96.9%) or good (3.1%), including major bleeds (6 excellent and 1 good). The median number of infusions required to treat bleeding events in the trial was 1 and the majority of events (81.8%) were resolved with a single infusion.
The multi-center, open-label clinical trial was designed to assess the safety, efficacy and pharmacokinetics of BAX 111 among patients with severe von Willebrand disease aged 18 to 65 years. Bleeding events that occurred during the study were treated with rVWF (40-60 IU/kg; up to 80 IU/kg for major bleeds) initially together with rFVIII and subsequently alone if hemostatic FVIII levels were maintained. rVWF pharmacokinetic (PK) parameters were determined with and without rFVIII and repeated after 6 months for rVWF; these analyses found that rVWF PK was not affected by administration together with rFVIII.
The recombinant technology used to produce BAX 111 avoids certain protein maturation processes that typically occur with plasma fractionation. This preserves large functional units known as ultra large multimers, which have been shown to be efficient in clot formation and FVIII stabilization.
No patients developed inhibitors or binding antibodies to the treatment, and there were no reports of thrombotic events or severe allergic reactions. Eight adverse events (AEs) were considered causally related to BAX 111: six non-serious related AEs occurred in four patients, and two related serious AEs (chest discomfort and increased heart rate) occurred in one patient.
The data support the application Baxter submitted to the United States Food and Drug Administration (FDA) in late 2014 for approval of BAX 111. Both the European Commission and the FDA have granted orphan-drug designation for BAX 111.
Von Willebrand Disease (VWD) is an autosomal genetic disorder related to quantitative deficits and/or qualitative defects of VWF, the result of which is impaired hemostasis. It is the most common hereditary coagulation disorder, occurring in approximately one to two percent of the general population. Many people who have VWD may experience mild symptoms, but some patients can experience severe bleeding events similar to bleeding experienced by patients with hemophilia.
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