Inclusion Criteria:

          -  Patients with a diagnosis of relapsed or refractory AML (or biphenotypic or bilineage
             leukemia including a myeloid component). Patients with isolated extramedullary AML are
             eligible

          -  Age >= 18 years

          -  Eastern Cooperative Oncology Group (ECOG) performance status =< 2

          -  Creatinine < 2 unless related to the disease

          -  Direct bilirubin < 2 x upper limit of normal (ULN) unless increase is due to Gilbert's
             disease or leukemic involvement

          -  Aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) < 3 x ULN
             unless considered due to leukemic involvement

          -  In the absence of rapidly proliferative disease, the interval from prior treatment to
             time of initiation will be at least 7 days for cytotoxic or non-cytotoxic
             (immunotherapy) agents. Oral hydroxyurea and/or cytarabine (up to 2 g/m^2) for
             patients with rapidly proliferative disease is allowed before the start of study
             therapy, as needed, for clinical benefit and after discussion with the principal
             investigator (PI). Concurrent therapy for central nervous system (CNS) prophylaxis or
             continuation of therapy for controlled CNS disease is permitted

          -  Male subjects must agree to refrain from unprotected sex and sperm donation from
             initial study drug administration until 90 days after the last dose of study drug

          -  Willing and able to provide informed consent

        Exclusion Criteria:

          -  Patients with t(15;17) karyotypic abnormality or acute promyelocytic leukemia
             (French-American-British [FAB] class M3-AML)

          -  Patients with active graft-versus-host-disease (GVHD) status post stem cell transplant
             (patients without active GVHD on chronic suppressive immunosuppression and/or
             phototherapy for chronic skin GVHD are permitted after discussion with the PI)

          -  Patients with any severe gastrointestinal or metabolic condition which could interfere
             with the absorption of oral study medications as determined by the investigator

          -  Patients with symptomatic CNS leukemia or patients with poorly controlled CNS leukemia

          -  Active and uncontrolled comorbidities including active uncontrolled infection,
             uncontrolled hypertension despite adequate medical therapy, active and uncontrolled
             congestive heart failure New York Heart Association (NYHA) class III/IV, clinically
             significant and uncontrolled arrhythmia as judged by the treating physician

          -  Known active hepatitis B (HBV) or hepatitis C (HCV) infection or known human
             immunodeficiency virus (HIV) infection

          -  Subject has a white blood cell count > 10 x 10^9/L. (Note: Hydroxyurea is permitted to
             meet this criterion)

          -  Any other medical, psychological, or social condition that may interfere with study
             participation or compliance, or compromise patient safety in the opinion of the
             investigator

          -  Nursing women, women of childbearing potential (WOCBP) with positive urine or serum
             pregnancy test, or women of childbearing potential who are not willing to maintain
             adequate contraception

               -  Appropriate highly effective method(s) of contraception include oral or
                  injectable hormonal birth control, intrauterine device (IUD), and double barrier
                  methods (for example a condom in combination with a spermicide)