Once-A-Day Prophylaxis for Youth and Young Adults With Severe Hemophilia A

Pilot Study of Once-A-Day Prophylaxis for Youth and Young Adults With Severe Hemophilia A

The primary objective of this study is to test the feasibility of a large-scale clinical trial of once-daily prophylaxis. The secondary objectives are to collect clinical efficacy outcomes so that we can better plan a large-scale study; we will estimate the effect size and variability of effect and resource utilization of once-daily prophylaxis to allow us to set a sample size for a definitive trial.

Hemophilia is an important and costly disorder; if left untreated, it may have serious consequences. The greatest impact of hemophilia occurs from recurrent bleeding into joints. The consequences of joint bleeding include pain associated with acute bleeding and later chronic arthropathy. Half of affected children with severe hemophilia have joint damage; joint damage is more frequent with increased bleeding. The prevention and treatment of bleeding is very expensive and therefore finding a cost-effective treatment is of high priority.

Worldwide, two major treatment strategies have been used to prevent arthropathy - on demand therapy and factor prophylaxis. The goal of prophylaxis is to convert the severe to the moderate phenotype by providing circulating factor activity of greater than 1%. Patients with greater than 1% circulating factor VIII activity rarely have spontaneous hemarthroses. Therefore, the goal of providing circulating factor at this level is to eliminate spontaneous hemarthroses. The term primary prophylaxis suggests using preventative factor VIII replacement from a very early age. The term secondary prophylaxis is used to describe the application of prophylaxis at a later disease stage. In this study, secondary prophylaxis will be used.

Once-daily prophylaxis is a novel application of hemophilia factor prophylaxis for youth and young adults. Before embarking on a costly definitive trial we feel that it is necessary to demonstrate that subjects will be willing to enroll and will be compliant with the therapy. Moreover, we need to establish an estimate of the effect of once-daily prophylaxis on bleeding rates, quality of life, and joint damage progression in order to design a definitive trial.

Inclusion Criteria:

• Severe hemophilia A (<1% factor VIII)
• Age 12 to 24 years inclusive
• Male
• No current factor VIII inhibitor (an inhibitor will be defined as ≥ 0.6 Bethesda Units) within the past year
• Able to participate in a home infusion program with adequate peripheral venous access as assessed ny the treating investigator

Exclusion Criteria:

• Important co-morbidities (Acquired Immunodeficiency Syndrome or symptomatic HIV infection, symptomatic hepatitis B or C infection)
• Other concomitant acquired or congenital bleeding disorder (e.g. von Willebrand's Disease)
• Receiving factor VIII replacement through central venous catheter