RATIONALE: Drugs used in chemotherapy work in different ways to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Giving more than one drug (combination chemotherapy) together with steroid therapy may kill more cancer cells.

PURPOSE: This clinical trial is studying the side effects of combination chemotherapy in treating young adult patients with acute lymphoblastic leukemia.

OBJECTIVES:

• To determine the feasibility of combination chemotherapy in young adult patients with acute lymphoid leukemia.
• To determine the complete response rate at the end of induction therapy in these patients.
• To determine the overall survival of patients treated with these regimens.
• To determine the disease-free survival of patients treated with these regimens.
• To determine the event-free survival of patients treated with these regimens.
• To determine toxicity of these regimens.
• To determine compliance related to dose intensity.

OUTLINE:

• Steroids prephase therapy: All patients receive steroids (i.e., prednisone or methylprednisolone) and methotrexate.

• Induction therapy (induction Ia followed by Ib): Patients receive induction Ia comprising vincristine, daunorubicin hydrochloride, asparaginase, and prednisone. They then receive induction Ib comprising cyclophosphamide, mercaptopurine, and cytarabine. Patients who achieve hematological remission proceed to consolidation therapy.

• Consolidation therapy: Patients receive consolidation therapy according to risk group.

  • Standard-risk patients: Patients receive high-dose methotrexate and mercaptopurine.

  • High-risk patients: Patients receive consolidation therapy in 3 steps.

    • Step 1: Patients receive dexamethasone, vincristine, methotrexate, cytarabine, and asparaginase.
    • Step 2: Patients receive dexamethasone, vindesine, methotrexate, ifosfamide, asparaginase, and daunorubicin hydrochloride.
    • Step 3: Patients receive dexamethasone, cytarabine, and asparaginase. After completion of consolidation therapy, patients proceed to reinduction therapy.

• Reinduction therapy (reinduction IIa followed by IIb): Patients receive reinduction IIa comprising vincristine, doxorubicin hydrochloride, asparaginase, and dexamethasone. Patients then receive reinduction IIb comprising cyclophosphamide, thioguanine, and cytarabine.

DISEASE CHARACTERISTICS:

• Diagnosis of acute lymphoid leukemia, meeting any of the following criteria:

  • Non-mature B-cell disease
  • Non-Philadelphia chromosome positive disease
  • T -cell or B-cell phenotype

PATIENT CHARACTERISTICS:

• Not specified

PRIOR CONCURRENT THERAPY:

• Prior pretreatment with antiblastic chemotherapy allowed