Eltrombopag: the emerging evidence of its therapeutic value in thrombocytopenia

Abstract

Idiopathic (immune) thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by low platelet counts and bleeding episodes. Current therapy options are associated with unwanted side effects, and although patients initially respond to treatment the platelet count is not sustained in many individuals. There is a need for safe and well-tolerated treatments that provide a sustained platelet response. This review summarizes the emerging evidence for the potential use of eltrombopag in the treatment of ITP in adults. Eltrombopag is a nonpeptide, small molecular weight thrombopoietin receptor agonist that is orally administered. It mimics the activity of thrombopoietin, a cytokine that promotes growth and production of platelets, primarily inducing proliferation and differentiation of megakaryocytes from bone marrow progenitor cells. Eltrombopag is still in the early stages of development but initial phase I and phase II results are promising. Potential advantages of eltrombopag may include a sustained platelet response and a good tolerability profile. Its once-daily oral dosing regimen would also be an advantage over many of the existing therapies. It is expected that patients who have failed first-line therapy with corticosteroids and wish to avoid the need for a splenectomy, and patients with chronic refractory ITP, may benefit from eltrombopag treatment.