Is there a role for eltrombopag drug levels in paediatric immune thrombocytopenia management?

Paediatric immune thrombocytopenia treatment was revolutionized with the advent of the thrombopoietin mimetics romiplostim and eltrombopag. For eltrombopag, dosing recommendations have been based on patients' ages (with dose reductions for those with hepatic impairment and for some of East Asian ethnicity) and titrated based on platelet counts and adverse drug reactions. However, it is clear that identical eltrombopag dosing for paediatric patients can result in variable side effects and platelet counts, raising the question as to whether variable eltrombopag plasma concentrations are responsible for these differing drug responses. Commentary on: Dong et al. Exploratory study on the individualized application of eltrombopag in paediatric immune thrombocytopenia guided by therapeutic drug monitoring. Br J Haematol 2024; 205:1930-1937.