⁃ Cohort 1 (R/R AML):

⁃ \- Patients with AML who have failed first line induction chemotherapy (consisting of a minimum of two intensive chemotherapy cycles, e.g. 7+3 or HAM) or patients with AML who have relapsed after achieving complete remission (CR), CRi, or CRp, or patients who have failed up to one prior salvage therapy

⁃ Cohort 2 (frontline older AML):

⁃ \- Patients aged ≥65 years with previously untreated AML who are unfit for or decline standard induction therapy.

• Patients not eligible for intensive induction chemotherapy and/or allogeneic stem cell transplant.

• Age ≥18 years

• ECOG Performance Status ≤2

• Adequate organ function:

⁃ Total bilirubin ≤2 x ULN (≤3 × ULN if due to leukemic involvement or Gilbert's syndrome) AST and ALT ≤2.5 × ULN (≤5.0 × ULN if due to leukemic involvement) Serum creatinine ≤2 × ULN or glomerular filtration rate (GFR) ≥50 mL/h

• Adequate cardiac function: TTE with documented LVEF ≥50%

• At least 2 weeks OR at least 5 half-lives interval from prior treatment to time of initiation of study medication

• GvHD of grade ≤A on ≤10 mg prednisone without any additional immunosuppressive therapies (tacrolimus, ciclosporin, etc.)

• Written informed consent

• Negative pregnancy test and adequate methods of contraception for females of childbearing potential, adequate methods of contraception for males