Alphanate in Immune Tolerance Induction Therapy

Male participants \<12 years of age with an inhibitor titer \>0.6 to \<10 Bethesda Units (BU) will be screened before the planned start of ITI treatment. Participants continuing to meet the entrance criteria will enter the ITI Treatment Phase and receive daily doses of alphanate 100 IU/kg/day for up to 33 months, with a one-time option to increase to a dosing regimen of 200 IU/kg/day at any time after 90 days of ITI treatment. Participants will continue to receive their daily alphanate dose for up to 33 months until the titer is negative (\<0.6 BU) on 2 consecutive assessments and treatment success is confirmed by FVIII:C pharmacokinetic assessments, at which time they will enter the 12-month Prophylactic Phase. In addition, participants who have achieved partial immune tolerance at the completion of 33 months of ITI treatment will enter the 12-month Prophylactic Phase. Participants who do not achieve partial immune tolerance at the completion of 33 months of ITI treatment will be discontinued as treatment failures. The Prophylactic Phase begins with an 8-week taper period for participants tolerized with 100 IU/kg/day or with a 12-week taper period for participants tolerized with 200 IU/kg/day to bring the dose down in a step-wise manner to a prophylactic dose of alphanate 50 IU/kg every other day or 3 times per week, at the investigator's discretion. During the Prophylactic Phase, participants will be monitored monthly for the first 4 months and then every 2 months for the remaining 8 months to assess sustainability of immune tolerance. Due to limited enrollment, this study was early terminated.