VWF and Von Willebrand disease: During the studies with von Willebrand factor/Factor VIII-von Willebrand disease (SWIFTLY-VWD) trial [24], 4 children who received prophylaxis with the pdVWF/FVIII concentrate Voncento (CSL Behring) experienced a median of 23.5 nonsurgical BEs during 12 to 13 months of prophylaxis.