QUESTIONS AND OBJECTIVES OF ALL-MB-2008 STUDY

1. Whether the early PEG-asparaginase in induction will lead to the earlier achievement of remission, improvement of days 8 and 15 responses leading to an earlier reconstitution of bone marrow and immunocompetence, decrease of severe infections and early mortality rate?
2. Whether the use of PEG-asparaginase in induction will allow to avoid the anthracyclines in standard risk group patients and to reduce treatment myelotoxicity?
3. Whether the administration of 9 doses of PEG-asparaginase 1,000 U/m2 instead of 18 doses of E.coli L-asparaginase 5,000 U/m2 in standard risk patients will improve treatment outcome?
4. Whether the administrations of high dose methotrexate (2 g/m2 in 24 hours) during 1-st consolidation in intermediate risk patients will result in decrease of central nervous system relapse incidence and improvement of event-free and overall survival? Whether the increase of 6-mercaptopurine starting dose up to 50 mg/m2 in 1-st consolidation phase (instead of 25 mg/m2) will decrease in relapse risk, but would not be accompanied with enhanced toxicity?
5. Is it possible to completely avoid the cranial irradiation in intermediate risk patients? In some subgroup of intermediate risk patients? Is it enough to control neuroleukemia in these patients to introduce additional TIT in the consolidation phase of treatment? How will change the possible late effects in these patients according to the third arm of randomization?
6. Will the new risk group stratification to improve overall and event-free survival?

Inclusion Criteria:

1. Age at diagnosis at 1 to 18 years.
2. The start of induction therapy within a time interval of study recruitment phase.
3. The diagnosis of ALL is to be proved by the morphological, cytochemical, and immunological analysis of tumor cells in bone marrow.
4. Informed consent of the parents (guardians) of the patient to be treated in one of the clinics included in this multicenter study.

Exclusion Criteria:

1. ALL is a second malignant tumor;
2. The disease is a relapse of previously misdiagnosed and, therefore, inadequately treated ALL;
3. There is severe concomitant disease, which significantly impedes chemotherapy protocol (such as multiple malformations, heart diseases, metabolic disorders, etc.);
4. There is a lack of important basic data needed for the exact adherence to the cytostatic therapy according to a specific protocol of chemotherapy (differential diagnosis of acute lymphoblastic/myeloid leukemia is not possible, stratification according to risk group is not possible);
5. The patient was treated before for a long time with cytotoxic drugs;
6. There were deviations in the treatment not covered by the protocol and/or not due to side effects of treatment and/or complications of the disease