Conditions: Severe Hemophilia A
Keywords: Hemophilia Prophylaxis Recombinant factor VIII
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 4
Healthy volunteers: no

Brief summary:
The purpose of this pilot R34 trial is to determine the feasibility of a large single dose Phase III study of hemophilia adult prophylaxis comparing once weekly with thrice-weekly recombinant factor VIII. Efficacy will measured by bleeding frequency, factor usage, joint range of motion, cost, quality-of-life, F.VIII level, and inter-dose hypocoagulability by thrombin generation. Safety will be measured by inhibitor formation and bleeding events unresponsive to up to two rescue doses.

Detailed description:
The purpose of this 52-week pilot R34 randomized, open-label, non-inferiority, cross-over study is to determine the feasibility of a large single dose Phase III study of hemophilia adult prophylaxis. The primary efficacy endpoint will be bleeding frequency. Secondary endpoints will include factor usage, joint range of motion, cost, quality-of-life, and inter-dose hypocoagulability by thrombin generation time and F.VIII activity will also be determined. Safety will be measured by the frequency of bleeding unresponsive to up to two rescue treatments. Inhibitor formation by anti-F.VIII Bethesda assay, and clinical frequency of thrombosis and allergic reactions will also be assessed. Subject acceptance and adherence to the treatment interventions will be determined; and web-based data entry of case report forms, digital range-of-motion images, and quality-of-life instrument will be implemented. The relation of bleeding frequency to relative inter-dose hypocoagulability, will be assessed by inter-dose thrombin generation time (TGT), endogenous thrombin potential (ETP), and factor VIII levels. Optimal blood sample collection and shipping methods will be determined. For all tests, we will estimate and determine completeness and congruency, in order to determine adjustments or revisions required before initiating a large phase III Randomized clinical trial. All testing will be exploratory, so that we may determine if the test, approach are realistic, and to estimate standard deviations for future power analyses.

Arms:
arm 1: The intervention for Arm A is 40 IU/kg recombinant factor VIII (rFVIII) by once-weekly intravenous injection for 26 weeks.

Cross-over will occur at 26 weeks after a 72 hour washout period, after which 40 IU/kg recombinant factor VIII (rFVIII) will be given thrice-weekly by intravenous injection until week 52, with up to two rescue doses per week for bleeds. arm 2: The intervention for Arm B is 40 IU/kg recombinant factor VIII (rFVIII) by thrice-weekly intravenous injection for 26 weeks.

Cross-over will occur at 26 weeks after a 72 hour washout period, after which 40 IU/kg recombinant factor VIII (rFVIII) will be given once-weekly by intravenous injection until week 52, with up to two rescue doses per week for bleeds

Interventions: intervention 1: rF.VIII
Intervention descriptions: intervention 1: 40 IU/kg recombinant factor VIII will be given once-weekly or thrice-weekly by intravenous injection for 26 weeks. At 26 weeks after a 72 hour washout period, 40 IU/kg recombinant factor VIII will be given thrice-weekly or once-weekly, respectively, by intravenous injection until week 52, with up to two rescue doses per week for bleeds

Protocol document: