• Disease Free Survival : time from randomization to relapse, death in complete remission (CR), second malignancies
  

• To Determine the safety and feasibility of Imatinib added to chemotherapy,
  
• To Evaluate the long-term clinical outcome (EFS, survival) in both groups,
  
• To Assess the antileukemic potential of Imatinib by analyzing the pattern by arm of the molecular response on the basis of 5 measurements of minimal residual disease (MRD) taken at 5 time points between S4 and S22,
  
• To evaluate the role of molecular response as surrogate for DFS.
  

Recent advances in treatment have increased the cure of childhood ALL to 75% or better. However, attempts to improve results for resistant subtypes of ALL, such as Ph+ ALL, have been largely unsuccessful. Imatinib, an inhibitor of protein-tyrosine kinases, is currently being tested in several phase I, II and III trials covering most Chronic Myeloid Leukemia patient populations and patients with overtly relapsed or refractory Ph+ALL. Pediatric patients with Ph+ALL will be stratified as Good-risk and Poor-risk, according to their initial prednisone and chemotherapy responses and the achievement of the complete remission at day 28. The Good-risk patients will be randomized to receive or not Imatinib whereas all Poor-risk patients will receive Imatinib, added to intensive, post-induction BFM-type chemotherapy. The endpoint will be the evaluation on the long-term clinical outcome, in particular on the Disease Free Survival (DFS).