The study evaluates the efficacy and tolerability of a dose-reduced chemotherapy for the treatment of elderly patients with acute lymphoblastic leukemia. In patients with expression of CD20 on leukemic cells the efficacy and tolerability of additional application of Rituximab together with chemotherapy is evaluated.

Inclusion Criteria:

• Diagnosis of acute lymphoblastic leukemia (pro B, pre B, c-ALL or T-ALL), proved by morphology and immunophenotyping
• Age > 55 yrs (no upper age limit)
• Written informed consent

Exclusion Criteria:

• Severe leukemia associated complications, not controllable before therapy onset e.g.
• life threatening infections as sepsis, pneumonia, hypoxia, shock, life threatening bleeding)
• Severe comorbidity e.g.
• decompensated renal failure if not caused by leukemia with Creatinine > 2x ULN
• heart failure (NYHA II/IV), instable Angina, significant coronary stenosis
• hepatic insufficiency e.g. liver cirrhosis or chronic active hepatitis with bilirubin > 1,5 x ULN and/or ASA, ALA, AP > 2,5 ULN
• decompensated metabolic disturbances (e.g. not controllable diabetes)
• severe obstructive or restrictive pulmonary disease with hypoxaemia
• Severe psychiatric illness or other circumstances which may compromise cooperation of the patient
• Active second neoplasia
• HIV infection
• Severely reduced general condition
• Cytostatic pre-treatment of ALL
• Chemotherapy treatment of any other malignancy during the last 5 years
• Participation in other clinical trials interfering with the study therapy