Rituximab as an adjuvant therapy to immune tolerance in a haemophilia A boy with high inhibitor titre.

We report a haemophilia A boy with high inhibitor titre (170 BU) who experienced five life-threatening bleeding episodes during a one-year period from 9 to 21 months. At the age of 22 months, he received rituximab (375 mg m(-2) per dose) at one- and three-week intervals, three courses each and alternative daily treatment with factor VIII concentrate at doses of 100 units kg(-1) for 24 weeks and 50 units kg(-1) for the following 28 weeks. Although the pretreatment inhibitor level of 4.5 BU showed an anamnestic response reaching the maximum level of 200 BU at the 9th week of treatment, it gradually declined to 30 BU at the 22nd week and was constantly maintained at 25-30 BU for the following 30 weeks. Only three bleeding episodes of two haematomas and one haemarthrosis were found during the one-year treatment period. No opportunistic infection occured during this period.