A Study of Venetoclax in Combination With Navitoclax and Chemotherapy in Subjects With Relapsed/Refractory Acute Lymphoblastic Leukemia or Relapsed/Refractory Lymphoblastic Lymphoma

Inclusion Criteria:

- Must have relapsed or refractory acute lymphoblastic leukemia (ALL) or relapsed or
refractory lymphoblastic lymphoma (LL). Refractory is defined as persistent disease
after at least 2 courses of chemotherapy.

- Participants with ALL with Philadelphia chromosome or with an ABL class
targetable fusion are eligible.

- Participants with LL must have radiographic evidence of disease

- Must weigh greater than or equal to 20 kg.

- Must be able to swallow pills.

- Must have adequate hepatic and kidney function.

- Must have adequate performance status:

- Participants less than or equal to 16 years of age: Lansky greater than or equal
to 50

- Participants greater than 16 years of age: Karnofsky greater than or equal to 50
or Eastern Cooperative Oncology Group (ECOG) less than 3.

Exclusion Criteria:

- Participant has central nervous system (CNS) disease with cranial involvement that
requires radiation.

- Participants who are less than 100 days post-transplant, or greater than 100 days
post-transplant with active graft versus host disease (GVHD), or are still continuing
post-transplant immunosuppressant therapy within 7 days prior to the first dose of
study drug.

- Participants who have received any of the following prior to the first dose of study
drug:

- Inotuzumab within 30 days and must have ALT, AST and bilirubin < ULN.

- A biologic agent (i.e., monoclonal antibodies) for anti-neoplastic intent within
30 days

- CAR-T infusion or other cellular therapy within 30 days

- Any anti-cancer therapy including blinatumomab, chemotherapy, radiation therapy
targeted small molecule agents or investigational agents within 14 days, or 5
half-lives, whichever is shorter

- Exception: Philadelphia Chromosome (Ph)+ ALL subjects on TKIs at Screening
may enroll and remain on Tyrosine Kinase Inhibitor (TKI) therapy to control
disease

- Steroid therapy for anti-neoplastic intent within 5 days

- Hydroxyurea that is ongoing (hydroxyurea is permitted up to the first dose)

- A strong or moderate CYP3A inhibitor or inducer within 7 days

- Aspirin within 7 days, or 5 half-lives, whichever is longer

- An excluded antiplatelet/anticoagulant drug or a herbal supplement that affects
platelet function within 7 days, or 5 half-lives, whichever is longer

- Participants with malabsorption syndrome or any other condition that precludes enteral
administration.