Front-Line Tyrosine Kinase Inhibitors in Pediatric Chronic Myeloid Leukemia: A Study on Efficacy and Safety

SIMPLE SUMMARY: Tyrosine kinase inhibitors (TKIs) have significantly improved treatment outcomes in pediatric patients with chronic myeloid leukemia (CML). However, there is insufficient evidence suggesting the superiority of one TKI over another in terms of treatment response and long-term adverse events (AEs). We aimed to assess the efficacy and safety profiles of front-line TKIs among pediatric patients. The complete cytogenetic response rates were excellent for both imatinib and dasatinib at 12 months. However, patients treated with dasatinib exhibited significantly faster and higher cumulative rates of early, major, and deep molecular responses. Although both TKIs were well tolerated, a notable decline in height was observed with both TKIs, with a greater decrease observed in the dasatinib group during the last year of observation. Our findings confirm the efficacy of both TKIs; however, the long-term AEs associated with their use should be evaluated in a large cohort of pediatric patients. ABSTRACT: We conducted a retrospective study on 51 pediatric patients with newly diagnosed chronic myeloid leukemia chronic phase or accelerated phase. The patients were classified into the IMA group (N = 33), treated with imatinib, and the DSA group (N = 18), treated with dasatinib, as front-line tyrosine kinase inhibitors (TKIs). At 12 months, the rates of complete cytogenetic response were similar between the IMA group (92.3%) and DSA group (100%) (p = 0.305). However, the rate of early molecular response was higher in the DSA group than in the IMA group (100.0% vs. 80.0%, p = 0.043). By 12 and 24 months, the DSA group showed faster and higher cumulative rates of both major (DSA group: 72.2% and 100%, respectively; IMA group: 41.2% and 68.7%, respectively; p = 0.002) and deep molecular responses (DSA group: 26.0% and 43.6%, respectively; IMA group: 13.8% and 17.5%, respectively; p = 0.004). Both TKIs were well tolerated. Although the height standard deviation scores decreased in both groups, the height decline was greater in the DSA group between one and two years from the start of TKI therapy. In this study, dasatinib achieved faster and higher molecular responses with an acceptable safety profile. Further follow-up is necessary to assess the long-term outcomes of TKI treatment in children.