Study of First TIME Immunotolerance Induction in Severe Hemophilia A Patients With Inhibitor at High Risk of Failure: Comparison With FVIII Concentrates With or Without Von Willebrand Factor - RES.I.S.T. Naive

The presence of Factor VIII (FVIII) inhibitor prevents FVIII infusions from working properly and makes treatment of bleeding episodes very difficult. Having an inhibitor is a serious and life-threatening complication in patients with Hemophilia. The usual treatment of patients with FVIII inhibitors involves "immune tolerance induction" (ITI). Immune Tolerance means that the body can accept infused FVIII and that FVIII is again effective in controlling bleeds. ITI involves giving high doses of FVIII regularly until the inhibitor disappears. This treatment is not always effective. The inhibitor persists in about 1 in 5 patients who undergo ITI. There are 2 types of FVIII concentrates: FVIII concentrates derived from human plasma, which contain the von Willebrand factor, and concentrates of FVIII without VWF (recombinant or plasma derived). Both types of concentrates are commonly used to induce immune tolerance in patients with Hemophilia A. Retrospective studies in subjects with hemophilia and inhibitors at risk for failing ITI, have indicated a higher rate of success if patients were treated with von Willebrand containing factor VIII concentrates. It is not known whether the addition of Von Willebrand factor offers an advantage to achieving immune tolerance.