Inclusion Criteria:

REGISTRATION ELIGIBILITY CRITERIA (STEP 1)

• Newly diagnosed patients with CD-22 positive B-cell acute lymphoblastic leukemia (WHO criteria) are eligible.
• Patients with Burkitt type ALL are NOT eligible.
• Patients who have BCR-ABL fusion transcript determined by fluorescence in situ hybridization (FISH) or real time-polymerase chain reaction (RT-PCR) or t(9;22)(q34;q11) by cytogenetics are not eligible and should be considered for enrollment on studies that incorporate imatinib during induction; please note: flow cytometry is to be performed at the local reference lab and must include assessment of CD20 and CD22 positivity, as well as CD29 and CD22 anti-positivity.
• No prior therapy except for limited treatment (< 7 days) with corticosteroids or hydroxyurea and a single dose of intrathecal cytarabine.
• No prior therapy for acute leukemia except emergency therapy (corticosteroids or hydroxyurea) for blast cell crisis, superior vena cava syndrome, or renal failure due to leukemic infiltration of the kidneys; when indicated, leukapheresis or exchange transfusion is recommended to reduce the WBC.
• Single-dose intrathecal cytarabine is allowed prior to registration or prior to initiation of systematic therapy for patient convenience; systemic chemotherapy must begin within 72 hours of this intrathecal therapy.
• Patients receiving prior steroid therapy are eligible for study; the dose and duration of previous steroid therapy should be carefully documented on case report forms.
• Not pregnant and not nursing; for women of childbearing potential only, a negative urine or serum pregnancy test done =< 7 days prior to registration is required.
• Eastern Cooperative Oncology Group (ECOG) performance status 0-2 - Patients with down syndrome are excluded from this study.
• Aspartate aminotransferase (AST), alanine aminotransferase (ALT) =< 3 x upper limit of normal (ULN), unless suspected leukemic involvement of the liver.
• Direct bilirubin =< 3 x upper limit of normal (ULN), unless suspected leukemic involvement of the liver.
• Calculated (calc.) creatinine clearance >= 50 mL/min by Cockcroft-Gault.

RANDOMIZATION ELIGIBILITY CRITERIA (STEP 2) 

• Completion of remission induction therapy.
• Patients with M2 marrow or better are eligible; patients with M3 or M4 marrow (greater than 25% lymphoblasts) will not be eligible to be randomized:
  • Rating: M0, M1; Blast Cells (%): 0-5.0;
  • Rating: M2; Blast Cells (%): 5.1-25.0;
  • Rating: M3; Blast Cells (%): > 25-50;
  • Rating: M4; Blast Cells (%): > 50.0; 
  • The term "blast cell" includes any cell that cannot be classified as a more mature normal element, and includes "leukemic cells," pathologic lymphocytes, and stem cells.
• No ascites, effusions or significant edema.
• Absolute neutrophil count (ANC) >= 1,000/mm^3.
• Platelet count >= 100,000/mm^3.
• Total bilirubin =< 1.5 x upper limit of normal (ULN), except for patients with known Gilbert's syndrome.
• Aspartate aminotransferase (AST) =< 8 x upper limit of normal (ULN).
• Completion of first 12 weeks (12+ weeks) of maintenance therapy (Course V).
• Patient has at least 24 weeks (24+ weeks) remaining before end of maintenance therapy (Course V).
• Patient is in complete continuous first remission at entry into A041501-HO1.
• Patient is receiving oral anti-metabolite chemotherapy during the maintenance phase of therapy; treatment plan must call for the following doses of antimetabolites: 6MP 75 mg/m2/day orally; methotrexate (MTX) 20 mg/m2/week orally (modification of 6 MP or MTX dosing based on laboratory or clinical parameters is acceptable).
• Patient is able and willing to use the Medication Event Monitoring System (MEMS) TrackCap (e.g. not using a pillbox).