Inclusion Criteria:

- Diagnosis of AML according to WHO criteria.

- Untreated relapse or refractory disease after a minimum of one standard induction
therapy. Treatment of relapse with leukocyte-apheresis or up to 5 days with low dose
cytarabine or hydroxyurea is allowed.

- Refractory disease is defined as ≥5% blasts after the second cycle of induction
therapy or no reduction in marrow blasts at early treatment assessment (day +15)
after the first cycle of induction therapy.

- Relapse is defined as an increase in bone marrow blast count ≥5%, re-appearance
of blasts in the peripheral blood or extramedullary disease.

- Age above 40 years.

- Have adequate renal and hepatic functions as indicated by the following laboratory
values:

- Serum creatinine <=1.0 mg/dL; if serum creatinine >1.0 mg/dL, then the estimated
glomerular filtration rate (GFR) must be >60 mL/min/1.73 m2 (see reference
below*)

- Serum bilirubin <=1.5× upper limit of normal (ULN)

- Aspartate transaminase (AST)/alanine transaminase (ALT) <=2.5× ULN

- Alkaline phosphatase <=2.5× ULN

- Eligibility for intensive chemotherapy

- Patient needs to be capable to understand the clinical trial as an investigational
approach to bridge the time to potential allogeneic HCT, potential risks and benefits
of the study.

- Signed written informed consent.

- Female patients of childbearing potential must have a negative serum

- Male and female patients must use an effective contraceptive method during the study
and for a minimum of 6 months after study treatment.

Exclusion Criteria:

- For refractory disease, more than two prior induction chemotherapies or more than one
prior salvage chemotherapy containing high-dose cytarabine (cumulative dose of
cytarabine ≥ 5 g/m2).

- Second or higher relapse. Patients who received hypomethylating agents like
azacytidine or decitabine as a treatment of first relapse, respond and relapse later
on may be included.

- Acute promyelocytic leukemia with t(15;17)(q22;q12) molecular detection or
(PML/RARα).

- Central nervous system involvement (i.e. WBC ≥ 5/µL in cerebrospinal fluid with
blasts present on cytospin).

- Prior allogeneic HCT

- Autologous transplantation within 100 days prior to start of study treatment

- Use of investigational agents or anticancer therapy within 10 days before study entry
with the exception of hydroxyurea or low-dose cytarabine.

- Have any other severe concurrent disease, or have a history of serious organ
dysfunction or disease involving the heart, kidney, liver, or other organ system that
may place the patient at undue risk to undergo transplantation.

- Patients with known refractoriness to platelet support.

- Patients with a systemic fungal, bacterial, viral, or other infection not controlled
(defined as exhibiting ongoing signs/symptoms related to the infection and without
improvement, despite appropriate antibiotics or other treatment).

- Pregnant or lactating patients.

- Any significant concurrent disease, illness, or psychiatric disorder that would
compromise patient safety or compliance, interfere with consent, study participation,
follow up, or interpretation of study results.