Continuous infusion therapy with very high purity von Willebrand factor concentrate in patients with severe von Willebrand disease

Five patients with severe (type III) von Willebrand disease received, by continuous infusion, a solvent-detergent treated von Willebrand factor high purity concentrate to control haemostasis. The clinical indications for treatment included prophylaxis prior to orthopaedic, abdominal and tympanic membrane surgery, and treatment of epistaxis and trauma-related bleeding. Plasma vWf antigen and activity were normalized sooner than factor VIII:C levels after initial bolus followed by infusion of the concentrate. Haemostasis was established in all five patients. The degree of shortening of the bleeding time correlated with concentrate infusion rate and, therefore, with administered dose of high molecular weight multimers. Concentrate clearance decreased over time with continued infusion. The product was shown to be stable and sterile at 24 h after reconstitution with no evidence of neoantigen expression. This report illustrates the effectiveness of high purity vWf concentrate administered by continuous infusion and shows that high-molecular-weight multimers are required to shorten the bleeding time to within the normal range.