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 produced by recombinant-DNA technology) were used to achieve immune tolerance in five patients with high-responding inhibitors to FVIII. The mean time required for inhibitor disappearance was 5 months. Four out of five patients showed normalisation of the half-life of infused FVIII after 8-18 months of treatment with 100 IU FVIII/kg body weight administered once daily. Highly purified FVIII products thus appear to be suitable for achieving immune tolerance without negative effects on endogenous von Willebrand factor levels and activity.