100% Efficacy in Pivotal Trial of Recombinant von Willebrand Factor Used to Treat Severe von Willebrand Disease

The efficacy of Baxter International’s investigational recombinant von Willebrand factor (rVWF) was rated “excellent” (96.9%) or “good” (3.1%) for treatment of 192 bleeding events in 22 patients with severe von Willebrand disease who were enrolled in a Phase 3 clinical trial. This multi-center, open-label trial was designed to assess the safety, efficacy and pharmacokinetics of this highly purified rVWF (BAX 111) among patients aged 18 years to 65 years.

On-study bleeding events were treated with 40-60 IU/kg of BAX 111; major bleeds were treated with up to 80 IU/kg. Initial bleeds were treated together with recombinant factor VIII, and subsequently alone if hemostatic factor VIII levels were maintained. The median number of infusions required to treat bleeding events was one, and most events (81.8%) were resolved with a single infusion. No patients developed inhibitors or binding antibodies. There were six nonserious adverse events (AEs) considered causally related to the product; two related serious AEs (chest discomfort and increased heart rate) occurred in one patient.

The investigators concluded that the trial met its primary efficacy endpoint, defined by the number of patients who achieved treatment success for control of bleeding episodes. Baxter submitted a biologics license application to the U.S. Food and Drug Administration for approval of BAX 111 in late 2014.