Long-term results of high-dose imatinib in children and adolescents with chronic myeloid leukaemia in chronic phase: the Italian experience

Imatinib mesylate (IM) is used for the management of childhood chronic myeloid leukaemia (CML). The most effective dosage of IM and its long-term efficacy in children are not well defined. The purpose of this multicentre study is to report on the long-term results of high-dose IM (340mg/m(2)/d) in CML patients in chronic phase (CP-CML) aged <18years at diagnosis. A total of 47 CP-CML patients with a median age at diagnosis of 11years 9months were enrolled in nine Italian centres. Complete cytogenetic response was achieved in 915% of the evaluable patients at a median time of 6months. BCR-ABL1 International Scale01% (major molecular response; MMR) and 001% (molecular response; MR) at 12months were 666% and 33%, respectively. During follow-up, MMR and MR were achieved in 786% and 61% of children, respectively. IM was safely discontinued in 3 long-term treated children with a durable MR. Twelve patients (eight cytogenetic/molecular responders) underwent stem cell transplantation. The progression-free survival probabilities at 96months for responding patients who continued IM and for those transplanted were 60% and 50%, respectively. After a median follow-up of 52months (range 3-146), all patients are alive. High-dose IM is a long-term effective therapy in children and adolescents with CP-CML.