The study evaluates the efficacy and tolerability of an intensified induction and consolidation therapy. Thereafter patients receive individualised treatment stratified according to relapse risk with stem cell transplantation for patients with high and very high risk of relapse. Patients with standard risk receive further consolidation and reinduction chemotherapy. In parallel minimal residual disease (MRD) is evaluated. After six months and one year the decision on intensification or discontinuation of therapy is made based on the results of MRD evaluation.

Inclusion Criteria:

• Acute lymphoblastic leukemia (pro-B, common, pre-B, early T, thymic T, mature T)
• Age 15-65 yrs (*55-65 years if biologically younger according to general condition)
• Written informed consent

Exclusion Criteria:

• Severe comorbidity or leukemia associated complications
• Late relapse of pediatric ALL or ALL as second malignancy
• Cytostatic pre-treatment
• Pregnancy
• Severe psychiatric illness or other circumstances which may compromise cooperation of the patient
• Participation in other clinical trials interfering with the study therapy