Clinical Analysis Of Imatinib Treatment In Children With Chronic Myeloid Leukemia

Objective: To evaluate the efficacy and tolerability of imatinib in children with chronic myeloid leukemia(CML),and to investigate the prognostic measurement value to early molecular response(EMR)in pediatric CML in chronic phase(CML-CP).Methods: 1.Between May 2014 to February 2018,twenty-one children(less than 18-year-old)with newly diagnosed CML and treated with imatinib in our hospital were enrolled in this study.The disease was staged according to the European LeukemiaNet(ELN)criteria and imatinib dose was determined according to the disease stage.Cumulative responses and survival probabilities were estimated according to the Kaplan-Meier method.2.Eighteen patients(less than 18-year-old)with newly diagnosed CML-CP and treated with imatinib more than 12 months in our hospital were enrolled in this study.The group were divided according to the 10%cutoff of 3-month BCR-ABL1 transcript level.Cumulative responses and survival probabilities were estimated by the Kaplan-Meier method and compared by log-rank test.Results: 1.The estimated complete hematologic response(CHR)rate of CML-CP was 89.5% at 3 months;complete cytogenetic response(CCyR)rates increased with time,reaching 47.4%,73.7%,and 80.3% at 6 months,12 months,and 24 months,respectively;cumulative major molecular response(MMR)rates were 42.1% and 76.3% at 12 months and 24 months,respectively.2.With a median follow-up times of 30.8 months(range,3.2 – 58.6months),the estimated overall survival(OS)rate of CML was 95.2%,95%CI(99.3%,70.7%)at 54 months.None of CML-CP patients progress to advanced phase(AP)and blast crisis(BC).The OS and progression-free survival(PFS)of CML-CP cohort was 100 % at 54 months,while the estimated event-free survival(EFS)was 67.4%,95% CI(83.9%,41.2%)at54 months.3.None of the patients in this group had treatment-related death or discontinuance of imatinib,and only one patient experienced grade III-IV non-hematological adverse effects.Overall,anemia was the most common adverse effect.Hematologic adverse effects were mainly anemia and neutropenia.The most common non-hematological adverse effect was gastrointestinal,and 56.3% of children showed a decrease in bone density.4.Children with BCR-ABL1 IS>10% after imatinib commencement for 3 months had a higher white blood cell count compared with those with BCR-ABL1 IS?10%(t = 2.65,P = 0.017).5.Children with BCR-ABL1 IS?10% at 3 months had higher cumulative incidence of CCyR and MMR at 12 months compared with those with BCR-ABL1 IS>10% : 100% vs.50%(P = 0.002),60% vs.25%(P = 0.046),respectively.6.With a median follow-up times of 20.4 months(range,7-58.6months),children with BCR-ABL1 IS?10% at 3 months was associated with superior event-free survival(EFS)at 48 months compared with those with BCR-ABL1 IS>10%(88.9% vs.37.5%,P=0.019).Conclusion: 1.Imatinib is effective in the treatment of pediatric CML and the adverse effects can be tolerated.2.The 10% cutoff of BCR-ABL1 transcript level at 3 months after starting imatinib may predict the prognosis of pediatric CML.