Eltrombopag in immune thrombocytopenia: efficacy review and update on drug safety

Immune thrombocytopenia (ITP) is an autoimmune disorder that induces a decrease in the number of circulating platelets due to spleen destruction and inability of megakaryocytes to restore normal counts. Immunosuppressive therapy with glucocorticoid drugs constitutes the first line of treatment. However, lack of response to these agents is not uncommon, and the management of refractory patients is a matter of controversy. In fact, day-to-day clinical practice shows that, in spite of the current guidelines, splenectomy, which is currently considered a suitable second-choice therapy, is being replaced by treatment with thrombopoietin receptor agonists. These boost platelet production by megakaryocytes. The use of one of these, namely eltrombopag, has been permitted for ITP patients refractory to first-line drugs or splenectomy, for the last 10 years. This review summarizes the experience reported using eltrombopag in ITP, paying attention to efficacy and safety. Results from clinical trials will be discussed, and studies performed in the course of daily clinical practice will also be reviewed, as these are useful to assess the potential of the drug in real-world settings. The management of adverse events and the use of eltrombopag in particular situations will also be covered. The experience reported so far permits us to suggest that eltrombopag efficiently induces recovery of platelet counts. Furthermore, recent papers have demonstrated that a sustained response after discontinuation, initially thought to be problematic, may be possible in a nonnegligible number of cases. The safety profile is satisfactory, although patients presenting with thromboembolism risk factors should be treated with caution until the eltrombopag-associated prothrombotic risk is fully established. In summary, although larger studies are still needed to clarify some issues, eltrombopag may be a useful alternative tool for ITP patients refractory to conventional medical management or splenectomy.