Successful immune tolerance treatment with monoclonal or recombinant factor VIII concentrates in high responding inhibitor patients

Very high purity factor VIII (FVIII) concentrates (plasma-derived or produc ed by recombinant-DNA technology) were used to achieve immune tolerance in five patients with high-responding inhibitors to FVIII, The mean time requi red for inhibitor disappearance was 5 months. Four out of five patients sho wed normalisation of the half-life of infused FVIII after 8-18 months of tr eatment with 100 IU FVIII/kg body weight administered once daily. Highly pu rified FVIII products thus appear to be suitable for achieving immune toler ance without negative effects on endogenous von Willebrand factor levels an d activity.