PRIMARY OBJECTIVES:

      I. To determine the complete remission (CR) rate and progression-free survival following
      treatment with hyperfractionated cyclophosphamide, vincristine sulfate, doxorubicin
      hydrochloride, and dexamethasone (hyper-CVAD) in combination with nelarabine in previously
      untreated patients with T-cell acute lymphoblastic leukemia (ALL) and T-cell lymphoblastic
      lymphoma.

      II. To determine the safety and overall survival of previously untreated patients with T-cell
      ALL and T-cell lymphoblastic lymphoma.

      III. To determine the safety and efficacy of adding pegaspargase to the regimen.

      IV. To determine the safety and efficacy of adding venetoclax to the regimen.

      OUTLINE:

      COURSES 1, 3, 5, and 7 (hyper-CVAD): Patients receive cyclophosphamide intravenously (IV)
      over 3 hours twice daily (BID) on day 1-3, doxorubicin IV over 24 hours on day 4, vincristine
      IV over 15-30 minutes on days 4 and 11, and dexamethasone IV or orally (PO) once daily (QD)
      on days 1-4 and 11-14.

      COURSES 2, 4, 6, and 8 (methotrexate/cytarabine): Patients receive methotrexate IV over 24
      hours on day 1 and cytarabine IV over 2 hours BID on days 2 and 3.

      Patients also receive venetoclax PO QD on days 1-14 of each course. Courses of hyper-CVAD and
      methotrexate/cytarabine repeat every 21 days in the absence of disease progression or
      unacceptable toxicity.

      Patients also receive nelarabine IV over 2 hours once daily (QD) for 5 days and pegaspargase
      IV over 2 hours on day 5 after completion of course 4 and after the completion of course 5 in
      the absence of disease progression or unacceptable toxicity.

      MAINTENANCE COURSES 1-5, 8-17, and 20-30 (mercaptopurine, vincristine, methotrexate, and
      prednisone [POMP]): Patients receive mercaptopurine PO thrice daily (TID), methotrexate PO
      once weekly, vincristine sulfate IV on day 1, prednisone PO QD on days 1-5, and venetoclax PO
      QD on days 1-7. Courses repeat every 28 days in the absence of disease progression or
      unacceptable toxicity.

      INTENSIFICATION COURSES 6 and 7: Patients receive nelarabine IV QD over 2 hours on days 1-5
      and pegaspargase IV over 2 hours on day 5. Patients also receive venetoclax PO QD on days
      1-14. Courses repeat every 21-35 days in the absence of disease progression or unacceptable
      toxicity.

      INTENSIFICATION COURSES 18 and 19: Patients receive methotrexate IV over 2 hours on day 1,
      pegaspargase IV over 2 hours on day 2, and venetoclax PO QD on days 1-14 in the absence of
      disease progression or unacceptable toxicity.

      POMP maintenance therapy continues for 30 months in the absence of disease progression or
      unacceptable toxicity.

      After completion of study treatment, patients are followed up every 3-6 months.