Inclusion Criteria:

          1. Patients aged ≥ 18 years

          2. Patients with cytologically confirmed and documented de novo, secondary or
             therapy-related AML as defined by World Health Organization 2016 classification
             (Arber, 2016) excluding acute promyelocytic leukaemia (APL, French American-British M3
             classification) with: relapsed or refractory disease and without established
             alternative therapy, or secondary to MyeloDysplastic Syndrome and without established
             alternative therapy or, newly diagnosed AML, not previously treated for AML and who
             are not candidate for intensive chemotherapy due to age or comorbidities.

          3. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2.

          4. Adequate haematological, renal and hepatic functions based on the last assessment
             performed within 7 days prior to the first Investigational Medicinal Product
             administration.

        Exclusion Criteria:

          1. Previous myeloproliferative syndrome (MPS).

          2. Patients previously treated with any Mcl-1 inhibitor.

          3. Patients who have not recovered from toxicity of previous anticancer therapy,
             including Grade ≥ 2 toxicity (except alopecia of any grade) according to the National
             Cancer Institute Common Terminology Criteria for Adverse Event (NCI CTCAE) version
             5.0, prior to the first IMP administration.

          4. Severe or uncontrolled active acute or chronic infection.

          5. Uncontrolled hepatitis B or C infection.

          6. Known carriers of HIV antibodies, history of significant liver disease, active acute
             or chronic pancreatitis, active central nervous system disease.

          7. Troponin > ULN (Upper Limit of reference range) or Troponin T > ULN if Troponin I
             cannot be assessed.

          8. Clinically significant cardiac dysfunction (including New York Heart Association class
             ≥II heart failure, Left Ventricular Ejection Fraction (LVEF) < 50% as assessed by
             echocardiography (ECHO) or Multi-Gated Acquisition (MUGA) scan).

          9. QT prolongation defined as QTc (QT interval corrected for heart rate) interval
             (corrected with Fridericia's formula) > 450 ms for males and > 470 ms for females,
             obtained from triplicate 12-lead ECG.

         10. Any factors that increase the risk of QTc prolongation or risk of arrhythmic events
             such as heart failure, hypokalaemia, congenital long QT syndrome, family history of
             long QT syndrome or unexplained sudden death under 40 years of age.

         11. Uncontrolled arterial hypertension (systolic blood pressure (SBP) > 150 mmHg or
             diastolic blood pressure (DBP) > 95 mmHg).