Evaluation and documentation on the ITI success rate in prospective and retrospective HA (hemophilia A) patients with newly developed or already existing FVIII- inhibitors, including patients with risk factors associated with a poor ITI prognosis, and those with prior ITI failure.
The efficacy of ITI, the primary endpoint of this observation, is defined according to the following criteria (The measure is a composite).: Inhibitor titre <0.6 BU, Incremental recovery of FVIII in the normal range,Half-life of FVIII > 7 hours. The efficacy of ITI, the primary endpoint of this observation, is defined according to the following criteria (The measure is a composite):
Inhibitor titre <0.6 BU (at least 2 consecutive determinations)
Incremental recovery of FVIII in the normal range (> 80% of normal) with samples taken prior to and 15 or 30 minutes after FVIII treatment.
Half-life of FVIII > 7 hours (blood samples for FVIII determination should be taken prior to and 15 or 30 minutes, 1, 2, 4, 8 and either 12 or 24 hours after FVIII treatment.

Complete Success:All three criteria above met.
Partial Success:Two of the three criteria above met.
Partial Response:One of the three criteria above met.
Partial Failure of ITI-treatment:Inhibitor still present, but titre has decreased to <5 BU.
Complete Failure of ITI-treatment:None of the above mentioned criteria met, and the inhibitor titre is still ≥5 BU.