Key Inclusion Criteria:

          -  Part A: Patients with relapsed or refractory AML, or newly-diagnosed AML secondary to
             MPN

          -  Part B: Patients with AML secondary to MPN or JAK2 mutation positive AML; patients may
             have been treated with 0 to 2 prior lines of therapy for their AML

          -  Adequate hepatic and renal function

          -  Appropriate prior treatment with an FLT3 or IDH1/2 inhibitor where applicable

        Key Exclusion Criteria:

          -  Patients who are TP53 mutation positive

          -  Prior treatment with an MDM2 antagonist therapy

          -  Patients treated with ≥ 18 g/m2 of cytarabine within the prior 90 days are not
             eligible to be treated with cytarabine on this study (but may be treated with
             decitabine)

          -  Patients previously treated with decitabine are not eligible to receive decitabine on
             this study (but may be treated with cytarabine)

          -  Patients who have received an allogeneic HSCT within 90 days of enrollment or are
             eligible for an allogeneic HSCT and have a donor (unless transplant is refused)

          -  Active graft-versus-host disease requiring active therapy or who have received
             immunosuppressive therapy for graft-versus-host disease within 1 month prior

          -  Patients with known CNS involvement with AML, acute promyelocytic leukemia (APL), or a
             history of bleeding diathesis

          -  Patients who have had major surgery within 28 days prior

          -  Women who are pregnant or breastfeeding