Study organization and leadership is provided by a Steering Committee composed of experts in the field of coagulation disorders.  Safety and data oversight is provided by Professor Christine Lee, Emeritus Professor of Haemophilia in the University of London, and an honorary consultant hematologist at the Oxford Haemophilia Centre, UK; and Professor John Hutter, Professor Emeritus of Pediatrics at the University of Arizona, Tucson, AZ, USA.  The VIP study has been approved by the Hemophilia and Thrombosis Research Society (HTRS), the American Thrombosis and Hemostasis Network (ATHN), and is officially recognized by the Von Willebrand Factor Scientific and Standardization Committee (SSC) of the International Society on Thrombosis and Haemostasis (ISTH).  It is registered at www.ClinicalTrials.gov.