Eltrombopag for the treatment of chronic immune thrombocytopenia

Author(s): Stavroula Tsiara, Nichola Cooper

Immune thrombocytopenic purpura (ITP) is an immune-mediated platelet disorder. Although early studies suggest that the main feature is antiplatelet antibody production and increased platelet clearance, more recent evidence implies that defective platelet production and suppressed maturation and differentiation of megakaryocytes also occurs. In this context, second-generation thrombopoietic agents, romiplostim and eltrombopag, have been developed for patients with chronic resistant/relapsing ITP. Eltrombopag has shown safety and efficacy in three double-blind randomized placebo-controlled multicenter studies. In these studies, a dose-dependent platelet increase to over 50 × 109 /l was achieved in 58–60% of the patients. Bleeding episodes were significantly less in patients receiving eltrombopag relative to placebo. Platelet counts returned to baseline within 2 weeks of discontinuation of eltrombopag. Adverse events were mild and similar in eltrombopag- and placebo-treated groups. Transaminases increased, and withdrawal thrombocytopenia and bleeding occurred in a minority of patients. Although not statistically significant, some parameters of quality of life estimation improved following eltrombopag treatment. These findings suggest that eltrombopag may allow patients with chronic resistant ITP to achieve safe platelet count, alleviate bleeding symptoms and improve ability to perform daily activities. Although significant toxicity was not observed in these patients, and lifestyles have been significantly improved, the potential need for long-term treatment and the cost of therapy are the main controversies for the widespread use of this therapeutic option.