Evaluating imatinib treatment in children and adolescents with chronic myeloid leukemia

The study evaluated the effectiveness and safety of imatinib (Gleevec) in treating children and adolescents with chronic myeloid leukemia (CML). The main finding was that imatinib was effective against CML and safe in this patient population.

Imatinib deactivates a cancerous enzyme called BCR-ABL1. Lately, imatinib has improved survival in adult patients with CML. CML is relatively rare in children and adolescents. They are generally treated by following adult guidelines. However, few studies established the safety and effectiveness of imatinib in pediatric patients.

The study included 21 patients aged 18 years or younger with newly diagnosed CML. All patients were treated with imatinib. 19 had chronic phase (CML-CP) and 2 had blast phase (CML-BP). Patients were followed up for 33.8 months on average.

Complete hematologic response (CHR) refers to the absence of immature leukemic cells in the blood. Among patients with CML-CP, CHR was achieved by 89.5% by 3 months and 94.7% by the end of follow-up. 1 patient with CML-BP had CHR in 3 months.

Complete cytogenetic response (CCyR) occurs when no bone-marrow cells are left with BCR-ABL1. In patients with CML-CP, CCyR rates reached 47.4% at 6 months, 73.7% at 12 months, and 80.3% at 24 months. 1 patient with CML-BP experienced CCyR in 3 months.

Major molecular response (MMR) means when 1 in 1000 blood cells have BCR-ABL1. The chances of experiencing MMR were 42.1% at 12 months and 76.3% at 24 months in this group. 1 patient in CML-BP group was left with 10% cells carrying BCR-ABL1 by 3 months.

Overall 95.2% of patients were estimated to survive for 2 years. No patient with CML-CP faced advanced phase leukemia. All patients in this group were estimated to survive with or without leukemia’s progression for 2 years. None of them had to stop therapy due to side effects to imatinib. 

The authors concluded that imatinib was safe and effective to treat CML in children and adolescents. 

This study was conducted on very few patients in one hospital in China. It also lacked a control group for comparing the effects of IM. Further studies on larger populations are needed.