Response to imatinib mesylate in childhood chronic myeloid leukemia in chronic phase: In pursuit of perfection

Abstract

Abstract Introduction: Childhood chronic myeloid leukemia (CML) accounts for less than 3% of all childhood leukemias, hence, data on imatinib (IM) in adult CML patients has been largely extrapolated to children. We have analyzed our data to add to the existing literature. Aims: Primary objective is to assess the progression-free survival (PFS). Secondary objective are cytogenetic response, overall survival (OS), and toxicities. Settings and Design: This is a retrospective analysis from the case records from a single institution. Materials and Methods: Institutional ethics committee approval was obtained. All the children diagnosed CML in chronic phase (CML-CP) aged less than 18 years registered between 2000 and 2009 were enrolled. All the patients were started on IM at 260 mg/m 2 . Statistical Analysis: Kaplan-Meier curves were used to calculate the PFS and OS. Results: There were 64 children with median age of 13 years (range, 1-18) with male predominance (male:female (M: F) - 1.85:1). Sixty-one patients (95.4%) achieved complete hematological response (CHR) at median of 8 weeks. Thirty-seven (57.8%) patients had evaluation of cytogenetic response and were subjects for outcome analysis. The median time to best cytogenetic response evaluation was 13 months (range, 4-52). Twenty-nine patients (78.3%) achieved complete cytogenetic response (CCyR). At a median follow-up of 36 months (range 5-75), 21 (56.8%) remained progression free and 35 (94.5%) are alive. Adverse events were tolerable. Conclusions: PFS at a median follow-up of 36 months is 56.8% and OS 94.5%.