- For many patients with von Willebrand disease (VWD), the replacement therapy with von Willebrand factor (VWF)/factor VIII (FVIII) concentrates is the treatment of choice. To evaluate clinical efficacy, safety and tolerability of Wilate, an albumin-free VWF/FVIII concentrate with a ratio of the two haemostatic moieties of approximately 1 to 1, a prospective clinical programme has been designed. The dataset on the treatment and prevention of bleedings is derived from 44 patients (20 males and 24 females) of all VWD types. Thousand and ninety five bleeding episodes were treated with an overall efficacy rating of excellent or good in 96%. The median dose per treatment day was 26 IU FVIII:C per kg. Eighty-one per cent of bleeds were stopped within 1 or 2 days. Gastrointestinal (GI) bleeds needed higher doses (mean 44 IU kg(-1)) and longer treatment (mean 4 days). Efficacy and dosing data from eight children of 12 or less years of age did not differ significantly from the overall study population. Nineteen patients, including six children, were treated prophylactically for more than 3 months (mean 14.8, range 3-46) with a mean prophylactic dose of 27.4 IU kg(-1) and a mean frequency of 1.9 infusions per week. A drop of bleeding frequency from a mean of 4.5 to 1.4 bleeds per month was observed. The overall tolerability was very good. Adverse drug reactions were rare and were mild or moderate in their intensity. The large prospective clinical dataset shows that Wilate is efficacious and safe in the treatment and prevention of haemorrhages in all VWD types in both adult and paediatric patients.