A Study to Assess the Safety and Efficacy of Eltrombopag in Japanese Subjects With Refractory, Moderate or More Severe Aplastic Anemia

This was a non-randomized, open-label, phase II study to assess the efficacy and safety of eltrombopag in Japanese moderate or more severe aplastic anemia (AA) subjects with a platelet count \<30,000/microliter who were refractory to anti-thymocyte globulin (ATG)-based immunosuppressive therapy (IST), who have relapsed after ATG-based IST, or who are ineligible for ATG-based IST. Eltrombopag was expected to improve trilineage blood cells and decrease transfusion frequency based on the result from the previous study in patients with severe AA. This study used the hematologic response rate, defined as the proportion of subjects showing improvement in at least one of the three blood cell lineages or a decrease in blood transfusion volume, as the primary endpoint. A total of 36 subjects were screened and 21 were enrolled in the study. Treatment with eltrombopag started at 25 milligram (mg)/day and increased by 25 mg/day every 2 weeks according to the platelet count up to 100 mg/day. Response assessment was performed at 3 months after starting the study treatment (Week 13). Subjects in whom the treatment was assessed as effective continued with the study treatment. Subjects in whom the treatment was assessed as effective (when meeting any of the response criteria) at 6 months after starting the study treatment (Week 26) might enter the extension phase and continue the treatment with eltrombopag. The primary endpoint was the hematologic response rate at Week26.