Inclusion Criteria:

          1. Signed informed consent is obtained prior to conducting any study-specific screening
             procedures.

          2. Willing and able to understand the nature of this study and to comply with the study
             and follow-up procedures.

          3. Age and Disease: ≥ 18 years of age with refractory or relapsed AML

             Refractory AML: Patients who fail to achieve a complete remission (CR) after one line
             of AML directed therapy

             Relapsed AML: Patients who achieved a complete remission (CR) with one or more prior
             lines of AML directed therapy but then developed a relapse of AML.

             Note: Patients are eligible even if they have not received intensive induction
             chemotherapy but have been treated with other AML directed therapy like
             hypomethylating agents (azacitidine, decitabine).

          4. Eastern Cooperative Oncology Group (ECOG) performance status must be ≤2

          5. Peripheral white blood cell (WBC) count <30,000/µL. For cyto-reduction, hydroxyurea is
             allowed during screening and through Cycle 2, Day 3 to reduce WBC count to < 30,000
             µL.

          6. Adequate organ function as evidenced by the following laboratory findings:

               -  Total bilirubin ≤ 1.5 × upper limit of normal (ULN) or < 3 x ULN for patients
                  with Gilbert-Meulengracht Syndrome

               -  Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 × ULN

               -  Creatinine clearance > 60 mL/min

          7. QT-interval corrected according to Fridericia's formula (QTcF) < 450 ms on one
             electrocardiogram (ECG) at screening

        Exclusion Criteria:

        Patients meeting any of the following criteria are ineligible for study entry:

          1. Uncontrolled intercurrent illness including, but not limited to, symptomatic
             congestive heart failure, unstable angina pectoris, cardiac arrhythmias not well
             controlled with medication, myocardial infarction within the previous 6 months before
             registration, or psychiatric illness/social situations that would limit compliance
             with study requirements.

          2. Patients may not be receiving any other concurrent investigational agents, or have
             received any investigational agent within one week of registration.

          3. Since the teratogenic potential of this combination is currently unknown, females who
             are pregnant or lactating are excluded.

          4. History of any other malignancies within the preceding 12 months before registration
             with the exception of in-situ cancer, non-muscle invasive bladder cancer, prostate,
             basal or squamous cell skin cancer

          5. Life-threatening illnesses other than AML, uncontrolled medical conditions or organ
             system dysfunction that, in the Investigator's opinion, could compromise the patient's
             safety or put the study outcomes at risk

          6. Evidence of isolated extramedullary disease

          7. Acute Promyelocytic Leukemia or AML with active central nervous system (CNS)
             involvement

          8. Untreated severe (in the opinion of the treating investigator) infection

          9. Active and uncontrolled infection with HIV (viral load is detectable by PCR)

         10. Active infection with Hepatitis B virus (HbSAg positive or PCR with detectable viral
             load) or Hepatitis C virus (viral load detectable by PCR).

         11. Past Hematopoietic stem cell transplant (HSCT) with active graft vs host disease,
             immunosuppression other than low dose prednisone (5 mg), or calcineurin inhibitors
             within the 4 weeks before registration