Eltrombopag, the first orally administered TPO-RA to receive global clinical approval, has been authorized by both the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the treatment of chronic immune thrombocytopenia (ITP), hepatitis C virus (HCV)-associated thrombocytopenia, and newly diagnosed or refractory severe aplastic anemia (SAA). This evidence concerns the gene TPO and severe aplastic anemia.