Eltrombopag as First-line Treatment for Thrombocytopenia among Pediatric Patients after Allogeneic Hematopoietic Stem Cell Transplantation.

OBJECTIVE The purpose of this study is to examine the safety and efficacy of eltrombopag as first-line treatment for thrombocytopenia among pediatric patients after HSCT. METHODS Forty-three childhood patients with thrombocytopenia after HSCT who received eltrombopag were retrospectively analyzed. RESULT Eltrombopag was began at the median of 27 days after HSCT and lasted for 24 days. Thirty-five children responded to eltrombopag therapy, and the cumulative platelet recovery rate was 88.9%. Obviously, the cumulative incidence of PLT recovery was lower (83.9% vs 100%; P=0.035) in patients with decreased numbers of megakaryocytes before starting eltrombopag than in those with normal. Factors associated with a significantly elevated response to eltrobopag from univariate analysis were donor tpye. Results from the multiple regression analysis found that weight (HR=0.7, 95%CI 0.5-0.9, P=0.022), platelet engraftment time (HR=1.0, 95%CI 1.0-1.0,P=0.012) and BM megakaryocytes (HR=8.0, 95%CI 1.5-43.3, P=0.016) before starting eltrombopag were the independent risk factors. Based on Youden's index algorithm in the ROC curve, the optimal cut-off value of the Maintenance dose of eltrombopag in predicting nonresponders was 4mg/kg, The AUC was 0.923 with sensitivity of 97.8%, specificity of 87.9%, PPV of 72.3%, and NPV of 92%. None of the pediatric patients stoped using eltrombopag due to side effect or intolerability. CONCLUSION Eltrombopag is effective and safe in pediatric patients with thrombocytopenia after HSCT. The number of megakaryocytes in bone marrow before eltrombopag treatment may serve as a predictor of the response to eltrombopag. We recommend that the maintenance dose of eltrombopag should not exceed 4mg/kg per day.