Study never opened.

This pilot study will investigate the use of thromboelastograph (TEG) to determine the primary bypassing agent for the management of bleeding in children and adults severe hemophilia A patients with inhibitors.

The study will evaluate the TEG profile for each of the available bypassing agents (FEIBA and rFVIIa) in each participating patient, which will then determine which agent provides the most robust clot formation as measured by the TEG. This study will consist of screening visit and 2-4 pharmacokinetic studies to determine the "best" bypassing agent based on the TEG results. Patients will then be assigned that bypassing agent and dose for the treatment of their bleeding episodes (Prophylaxis or On-demand). Each patient will be then followed for a period of 6 months to monitor short-term safety of those patients whose bypassing agent was modified.

Currently, there are no laboratory assays that can assess the pharmaceutical activity of the available agents known collectively as bypassing agents, which negatively impacts the treating physician's ability to manage these patients, leaving decisions on the dosing regimen to trial and error. Both agents, FEIBA and recombinant activated factor VII (rFVIIa), are approved for the treatment of bleeding in inhibitor patients with recommended dosing regimens that are based on clinical trials. However, a significant amount of "experimenting" with other dosing regimens is used by physicians and patients.

The goal of this project is to demonstrate that TEG is an excellent biomarker for predicting, managing and individualizing the treatment with FEIBA and rFVIIa of this rare and difficult to treat patient population.

Inclusion Criteria:

1. Males, 4-60 years old, inclusive on Prophylaxis or On-Demand treatment
2. Diagnosis of Hemophilia with active titer inhibitors (> 0.6 BU)
3. Willing to alter their treatment regimen per study protocol

Exclusion Criteria:

1. Bleeding disorder(s) other than hemophilia A with inhibitors
2. Thrombocytopenia (platelet count <100,000K/µL)
3. Any concurrent clinically significant major disease that, in the opinion of the investigator, would make the subject unsuitable for enrollment
4. Participation within the past 30 days in a clinical study involving investigational drugs
5. Planned major surgery within 30 days prior to screening or during the study period