In a multicenter international study consisting of 229 patients with VWD, 31 of whom had type 2 VWD, biological complete responses were demonstrated in 89%, defined by both VWF ristocetin cofactor (VWF:RCo; a marker of VWF binding to platelets) and FVIII:C > 50 U/dL, with 10% having partial response, defined by 3 fold increase and VWF:RCo or FVIII:C < 50 U/dL, and 1% with no response, defined by <3 fold increased and VWF:RCo or FVIII:C < 50 U/dL; there was a strong correlation found in patients with baseline VWF:Ag < 30 U/dL (Fisher’s exact = 0.001) [26]. This evidence concerns the gene VWF and von Willebrand disease (hereditary or acquired).