Inclusion Criteria:

          -  To be considered eligible for enrollment into this study, all of the following
             inclusion criteria must be met during the screening period:

          -  Documented AML by peripheral blood and bone marrow analyses meeting WHO criteria,
             excluding patients with acute promyelocytic leukemia (APL)

          -  Patients with AML refractory to primary induction chemotherapy, relapsed disease, or
             age ≥ 60 and not appropriate for standard cytotoxic therapy due to age, performance
             status, and/or adverse risk factors according to the treating physician

          -  Age ≥ 18 years

          -  Karnofsky performance status ≥ 50% or ECOG performance status 0-2

          -  Life expectancy ≥ 6 weeks

          -  Able to understand the investigational nature of this study and to provide written
             consent to participate in it

          -  Signed written IRB-approved Informed Consent document

          -  Adequate hepatic and renal function:

               -  serum bilirubin ≤ 1.5 X institutional ULN OR serum direct bilirubin ≤ 2 X
                  institutional ULN

               -  serum ALT and AST ≤ 2.5 X institutional ULN

               -  serum alkaline phosphatase < 5 X institutional ULN

               -  serum creatinine ≤ 2.0 mg/dL

               -  corrected calcium level ≥ institutional LLN

          -  Negative pregnancy test in women of child-bearing potential

          -  Women and men of child-producing potential must agree to use effective contraceptive
             methods during the study period (including post-treatment observation period)

        Exclusion Criteria:

          -  A patient will be considered not eligible for enrollment into this study if any of the
             following criteria are met during the screening period:

          -  Evidence of leukemic meningitis or other CNS involvement by leukemia

          -  Uncontrolled or poorly controlled hypertension (systolic BP ≥ 160 mmHg or diastolic BP
             ≥ 100 mmHg) Note: an isolated reading that is not sustained will be permitted.

          -  Evidence of NYHA Class III or IV cardiac disease, or presence of unstable
             life-threatening arrhythmia, or history of myocardial infarction during the past 6
             months

          -  Active bacterial, fungal, or viral infection requiring systemic treatment

          -  Known infection with HIV

          -  History or major surgery within 4 weeks before the first dose of study treatment, or
             not recovered from prior surgery

          -  Exposure to any other investigational agent at any time within 4 weeks before the
             first dose of study treatment

          -  Exposure to any other anti-leukemic therapy (except hydroxyurea, see Section 5.5.1)
             within 2 weeks before the first dose of study treatment

          -  Pregnant or lactating female

          -  Unwilling or unable to comply with the requirements of the study protocol