Higher Dose Imatinib for Children With De Novo Chronic Phase Chronic Myelogenous Leukemia: A Report From the Children's Oncology Group

Purpose. To determine the efficacy of imatinib in children with newly diagnosed chronic phase (CP) chronic myelogenous leukemia (CML). Methods. This was an open label, multi-center phase II clinical trial. Courses were defined as consecutive 28-day intervals. Oral imatinib was administered daily at 340 mg/m(2) without interruption in the absence of toxicity. Results. Fifty-one children received 978 28-day courses of imatinib. The most common toxicities encountered were hematologic. Forty-one patients (80%) achieved a complete hematologic response by the end of course 2. Nineteen children (38%) obtained a complete cytogenetic response (CCyR) at the end of course 3. Overall, 72% achieved CCyR at a median time of 5.6 months. The rate of complete molecular response (> 3 log reduction) was 27%. Progression-free and overall survival at 3 years were 72% +/- 6.4% and 92% +/- 3.9%, respectively. Conclusions. Daily oral imatinib at a dose of 340 mg/m(2) is well tolerated in children. In addition, imatinib therapy is effective in inducing a high percent of hematologic, cytogenetic and molecular responses, comparable to adults with CML. (This study was registered at ClinicalTrials.gov under identifier NCT00030394.) Pediatr Blood Cancer 2011;57:56-62. (C) 2011 Wiley-Liss, Inc.