Improved Early Event-Free Survival With Imatinib in Philadelphia Chromosome–Positive Acute Lymphoblastic Leukemia: A Children's Oncology Group Study

PURPOSE: Imatinib mesylate is a targeted agent that may be used against Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL), one of the highest risk pediatric ALL groups. PATIENTS AND METHODS: We evaluated whether imatinib (340 mg/m(2)/d) with an intensive chemotherapy regimen improved outcome in children ages 1 to 21 years with Ph+ ALL (N = 92) and compared toxicities to Ph- ALL patients (N = 65) given the same chemotherapy without imatinib. Exposure to imatinib was increased progressively in five patient cohorts that received imatinib from 42 (cohort 1; n = 7) to 280 continuous days (cohort 5; n = 50) before maintenance therapy. Patients with human leukocyte antigen (HLA) -identical…