Eltrombopag for the treatment of immune thrombocytopenia.

Chronic immune thrombocytopenia (ITP) is an autoimmune disorder characterized by a low platelet count that has persisted for more than 12 months. Patients with severe, symptomatic disease may have significant morbidity and require treatment. Historically, the underlying cause of ITP was believed to be accelerated platelet destruction by antiplatelet antibodies. Treatment options were therefore focused on reducing platelet autoantibody production or inhibiting macrophage-mediated platelet destruction. These treatments are not always effective or, at best, only have a transient effect and treatment-related adverse events often preclude their long-term use. Recently, impaired platelet production was observed in many ITP patients. Therefore, growth factor or growth factor analogs that stimulate megakaryopoiesis may be useful in ITP treatment. This article presents data on the pharmacology, clinical efficacy, safety profile and future roles of eltrombopag, an orally bioavailable, low-molecular-weight, synthetic nonpeptide thrombopoietin receptor agonist, in the treatment of ITP.