Eltrombopag and the Bcl-extra-large (xL) Pathway in Idiopathic Thrombocytopenic Purpura (ITP)

Inclusion Criteria: * Subject has signed and dated a written informed consent * Male or female adults (≥18 years) diagnosed with either primary ITP according to the American Society for Hematology or British Committee for Standards in Haematology (ASH/BCSH) guidelines \[Blood, 1996; British Journal of Haematology, 2003\] for at least three months prior to study entry or with ITP secondary to Evans syndrome, systemic lupus erythematosus (SLE), or Common Variable Immunodeficiency (including hypogammaglobulinemia). * Subjects must have responded with a platelet count \> 30,000/µL to a previous ITP therapy including thrombopoietic agents. * Platelet count \< 30,000/µL * Female subjects of childbearing potential are practicing an acceptable method of contraception or are completely abstinent from intercourse. Exclusion Criteria: * Active infection * Previously treated with thrombopoietic agents IF either no response at a therapeutic dose (peak platelet count \< 50k) OR treatment with the agent within the past 4 weeks * Currently treated with concomitant ITP medication that has not been stable in dose for at least 2 weeks - only prednisone, azathioprin, and danazol are allowed. * Female subjects who are nursing or pregnant * Thrombosis of any kind within past 6 months or on blood thinners because of thrombosis. * Intravenous Immunoglobulin (IVIG), IV anti-D, bolus corticosteroids or vinca alkaloids within the past week * Other cytotoxic or immunosuppressive ITP therapy within th…