PRIMARY OBJECTIVE:

      I. To evaluate the combined effect of blinatumomab and mini-hyper-CVD (low-intensity
      chemotherapy) on event-free survival.

      SECONDARY OBJECTIVES:

      I. Evaluating other clinical efficacy endpoints (minimal residual disease [MRD] negativity,
      duration of response, the overall response rate [complete response (CR) + CR with inadequate
      count recovery (CRi)]) of the regimen occurred any time during the treatment.

      II. Overall survival. III. Determining the safety of the combination regimen.

      OUTLINE:

      INDUCTION PHASE: Patients receive blinatumomab intravenously (IV) continuously on days 1-28
      and dexamethasone orally (PO) or IV over 30 minutes on days -3 to day 0 and 7-10. Patients
      also receive filgrastim subcutaneously (SC) on days 1-42 or pegfilgrastim SC on days 1 and
      25, cyclophosphamide IV over 3 hours twice daily (BID) on days -3 to -1, methotrexate
      intrathecally (IT) on day 2 and IV over 24 hours on day 22, cytarabine IT on day 7 and IV
      over 3 hours BID on days 23 and 24, and vincristine sulfate IV over 15 minutes on days 0 and
      7. At the discretion of the treating physician, patients may receive rituximab IV over 4-6
      hours on days -3, 0, 22 and 29, and leucovorin calcium IV over 15 minutes or PO 4 times daily
      (QID) for 8 doses.

      CONSOLIDATION PHASE: Patients receive blinatumomab IV continuously on days 1-28 and
      dexamethasone PO or IV over 30 minutes on days 1-4 and 11-14. Patients also receive
      cyclophosphamide IV over 3 hours BID on days 1-3, vincristine sulfate IV over 15 minutes on
      days 1 and 11, filgrastim SC on days 1-4 and 22-42 or pegfilgrastim SC on day 5 and 25,
      methotrexate IT on day 2 and IV over 24 hours on day 22, cytarabine IT on day 7 and IV over 3
      hours BID on days 23 and 24. At the discretion of the treating physician, patients may
      receive rituximab IV over 4-6 hours on days 1, 8, 22 and 29, and leucovorin calcium IV over
      15 minutes or PO QID for 8 doses. Treatment repeats every 42 days for up to 3 cycles in the
      absence of disease progression or unacceptable toxicity.

      MAINTENANCE PHASE: Patients receive prednisone PO and vincristine sulfate IV over 15 minutes
      on days 1-5 of cycles 5-9, 7-11 and 13-24, and mercaptopurine PO BID on days 1-28 of cycles
      1-5, 7-11, and 13-24. Patients also receive methotrexate PO once a week and blinatumomab IV
      continuously on days 1-28 of cycles 6 and 12. Cycles repeat every 28 days for up to 24 cycles
      (2 years) in the absence of disease progression or unacceptable toxicity.

      After completion of study treatment, patients are followed up at 30 days.