Inclusion Criteria:

          -  Patients with Philadelphia (Ph)+ acute myeloid leukemia (AML) or myeloid accelerated
             phase (AP)-chronic myelogenous leukemia (CML) or blast phase (BP)-CML (either t[9;22]
             and/or BCR-ABL1 positive by fluorescent in situ hybridization or polymerase chain
             reaction). Both untreated and relapsed/refractory patients are eligible

          -  Performance status =< 3 (Eastern Cooperative Oncology Group [ECOG] scale)

          -  Total serum bilirubin =< 2 x upper limit of normal (ULN), unless due to Gilbert's
             syndrome, hemolysis or the underlying leukemia approved by the principal investigator
             (PI)

          -  Alanine aminotransferase (ALT) =< 1.5 x ULN, unless due to the underlying leukemia
             approved by the PI

          -  Aspartate aminotransferase (AST) =< 1.5 x ULN unless due to the underlying leukemia
             approved by the PI

          -  Creatinine clearance >= 30 mL/min

          -  Serum lipase =< 1.5 x ULN

          -  Amylase =< 1.5 x ULN

          -  Ability to swallow

          -  Signed informed consent

        Exclusion Criteria:

          -  Active serious infection not controlled by oral or intravenous antibiotics (e.g.
             persistent fever or lack of improvement despite antimicrobial treatment)

          -  History of acute pancreatitis within 6 months of study or history of chronic
             pancreatitis

          -  Uncontrolled hypertriglyceridemia (triglycerides > 450 mg/dL)

          -  Active secondary malignancy that in the investigator's opinion will shorten survival
             to less than 1 year

          -  Active grade III-V cardiac failure as defined by the New York Heart Association
             criteria

          -  Clinically significant, uncontrolled, or active cardiovascular disease, specifically
             including, but not restricted to:

               -  Myocardial infarction (MI), stroke, revascularization, unstable angina or
                  transient ischemic attack within 6 months

               -  Left ventricular ejection fraction (LVEF) less than lower limit of normal per
                  local institutional standards prior to enrollment

               -  Diagnosed or suspected congenital long QT syndrome

               -  Clinically significant atrial or ventricular arrhythmias (such as uncontrolled,
                  clinically significant atrial fibrillation, ventricular tachycardia, ventricular
                  fibrillation, or torsades de pointes) as determined by the treating physician

               -  Prolonged corrected QT (QTc) interval on pre-entry electrocardiogram (> 480 msec)
                  unless corrected after electrolyte replacement

               -  History of venous thromboembolism including deep venous thrombosis or pulmonary
                  embolism within the past 3 months, excluding line-associated deep venous
                  thrombosis (DVT) of the upper extremity

               -  Uncontrolled hypertension (diastolic blood pressure > 100 mmHg; systolic > 150
                  mmHg)

          -  Consumed grapefruit, grapefruit products, Seville oranges, or star fruit within 3 days
             prior to starting venetoclax

          -  Treatment with any investigational antileukemic agents or chemotherapy agents in the
             last 7 days before study entry, unless full recovery from side effects has occurred or
             patient has rapidly progressive disease judged to be life-threatening by the
             investigator. Prior recent treatment with corticosteroids, hydroxyurea, or a Food and
             Drug Administration (FDA)-approved BCR-ABL tyrosine kinase inhibitor (TKI) is
             permitted

          -  Pregnant and lactating women will not be eligible; women of childbearing potential
             should have a negative pregnancy test prior to entering on the study and be willing to
             practice methods of contraception throughout the study period. Women do not have
             childbearing potential if they have had a hysterectomy or are postmenopausal without
             menses for 12 months. In addition, men enrolled on this study should understand the
             risks to any sexual partner of childbearing potential and should practice an effective
             method of birth control