Immune tolerance induction rescue with turoctocog-alfa in a poor risk haemophilia A inhibitor young child: the history of a success.

The development of alloantibodies against the replacement of Factor VIII (FVIII) is the major complication in haemophilia A treatment. The gold standard to eradicate inhibitors is the immune tolerance induction (ITI), but in some cases it fails requiring another immune tolerance, defined ITI rescue (ITI-R), using a different concentrate, even though it is still debated. We report a successful case of a poor risk (titre of inhibitor at start of ITI>10BU/ml, peak titre on ITI>200BU/ml, >2 years since the inhibitor diagnosis) haemophilia A child treated with a high-dose regimen (200UI/kg/day) turoctocog-alfa after a failed first-line ITI with octocog-alfa lasting 29 months. At 22 months of ITI-R, the inhibitor titre was undetectable, the FVIII recovery was 74%, of the expected level and the FVIII half-life more than 7h. A complete successful ITI-R was then achieved with turoctocog-alfa.