Immune tolerance induction in 31 children with haemophilia A: is ITI less successful in African Americans?

Inhibitor development continues to be a major problem in the treatment of haemophilia. Immune tolerance induction (ITI) continues to be the most effective approach to managing this complication. This study reviews the practice and outcome of ITI at a single centre over a 17-year period. All 31 inhibitor patients have haemophilia A. Two patients with haemophilia A underwent two trials of ITI and a third patient underwent three trials of ITI for a total of 35 courses of ITI in these 31 patients. Most patients had high responding inhibitors, 22 of 31. Seventy-one percent of haemophilia patients achieved tolerance. Courses of ITI in African American (AA) patients with haemophilia A were much less likely to achieve tolerance compared with non-AAs, 57.9% and 92% (P = 0.04) respectively. Most trials of ITI were carried out with recombinant products (25 of 35). While ITI continues to be an effective therapy for patients with inhibitors, it is less effective in AA patients, and patients with higher inhibitor titres. In this refractory group of patients, new approaches are needed.