Successful treatment of urgent bleeding in von Willebrand disease with factor VIII/VWF concentrate (Humate-P): use of the ristocetin cofactor assay (VWF:RCo) to measure potency and to guide therapy.

This prospective, open-label, non-randomized study evaluated the safety and efficacy of factor VIII (FVIII)/von Willebrand Factor (VWF) concentrate (Humate-P) using treatment regimens based on VWF:ristocetin cofactor (VWF:RCo) activity in patients with von Willebrand Disease (VWD) in (i) urgent bleeding episodes, or (ii) in patients undergoing urgent and necessary surgery. This article summarizes the results of treatment for the 33 patients with 53 urgent bleeding events. The median loading dose of FVIII/VWF concentrate was 67.0 international units per kilogram (IU kg(-1)) VWF:RCo (range 25.7-143.2 IU kg(-1)), and the median daily maintenance dose per infusion was 74.0 IU kg(-1) (range 16.4-182.9 IU kg(-1)) for a median duration of 2 days (range 1-34 days). The overall efficacy (achievement of haemostasis) of FVIII/VWF concentrate was rated as excellent/good for 98% of the urgent bleeding events. No unexpected treatment-related adverse events or serious drug-related adverse events (AEs) were observed. This study supports the safety and efficacy of Humate-P administered in doses calculated in VWF:RCo units for the treatment of urgent bleeding episodes in patients with VWD.