Adjunctive Effects of Eltrombopag on Immunosuppressive Therapy for Childhood Aplastic Anemia

Eltrombopag is used with first-line immunosuppressive therapy for adult aplastic anemia, although its practical utility in childhood remains unclear. We retrospectively analyzed the outcomes of pediatric patients who received eltrombopag in Japan. Of the 27 eligible patients, 23 (85%) were previously treated, and 15 (56%) had severe or very-severe disease. Seventeen (63%) received eltrombopag with or after rabbit anti-thymocyte globulin plus cyclosporin-A. Within the first year of eltrombopag therapy, 12 patients showed a good or partial response, 15 showed no response, and 8 non-responders successfully underwent hematopoietic cell transplantation. Within the first 3 months after eltrombopag therapy, all but one of the transfusion-dependent responders became transfusion-independent. At 12 months, 6 of 12 responders were disease-free off-treatment. The one-year overall response rate was higher for severe or very-severe than non-severe cases (p = 0.006). Multivariable analysis showed that very-severe disease at the start of eltrombopag therapy was a predictor of being disease-free off-treatment (p = 0.03). No cytogenetic abnormalities developed, but myelofibrosis occurred 4 months after eltrombopag therapy in one non-responder with very-severe disease. The first 3 months' response to adjunctive eltrombopag may guide to the safe and effective use for the cure of disease, although prospective trials are needed to determine its long-term effects.