Inclusion criteria

          1. AML patients who have either: (a) relapsed or are refractory to standard therapies
             (the patient may have been treated with standard therapy prior to the diagnosis of AML
             e.g. for MDS), OR (b) diagnosis of AML (bone marrow blasts ≥ 20%), who are previously
             untreated for AML, and are not suitable for intensive induction therapy, as defined
             below (for AZD2811 monotherapy and HMA combination patients only i.e. inclusion
             criteria 1(b) may only be used to enrol a patient into Groups 1 and 2; previously
             untreated AML patients may not enrol into Group 3 UNLESS they fulfil inclusion
             criteria 1(a) above).

             Patients are unsuitable for intensive induction therapy if they are:

               -  75 years or

                    -  75 years of age with clinically significant cardiac or pulmonary dysfunction
                       unrelated to leukaemia, as reflected by at least 1 of the following
                       criteria: Left ventricular ejection fraction (LVEF) ≤50% Diffusing capacity
                       of the lungs for carbon monoxide (DLCO) ≤65% of expected Forced expiratory
                       volume 1(FEV1) ≤65% of expected Chronic stable angina

             any significant co-morbidities which in the opinion of the treating physician makes
             the patient unsuitable for intensive induction therapy. This must be documented by the
             study monitor.

          2. AML patients who are unlikely to demonstrate rapid progression such that they would be
             unable to complete the first cycle of therapy.

          3. Provision of signed and dated, written informed consent prior to any study-specific
             procedures, sampling and analyses.

          4. Aged at least 18 years

          5. Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-2.

          6. Prior treatment with hydroxyurea (up to 24 hours before study treatment) is allowed

          7. Adequate organ system function as outlined below:

             PT/PTT ≤1.5 x upper limit of normal (ULN) Total bilirubin ≤1.5 x ULN. Patients with
             documented Gilbert's Syndrome (unconjugated hyperbilirubinemia) who have serum
             bilirubin ≤3 x the ULN may be enrolled, unless there is evidence of hemolytic anemia
             Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ˂2.5 x ULN if no
             liver involvement or ≤5 times the ULN with liver involvement Creatinine ≤1.5 x ULN, OR
             calculated or measured creatinine clearance ≥50 mL/min as calculated by the
             Cockcroft-Gault method, OR 24-hour measured urine creatinine clearance ≥50 mL/min.

             Patients enrolled in the venetoclax combination part with a CLcr <80 mL/min (and ≥ 45
             mL/min) as calculated by Cockcroft-Gault should be able to have more intensive
             prophylaxis and monitoring (according to institutional standard) to reduce the risk of
             TLS when initiating treatment with venetoclax.

          8. Females should be using adequate contraception, should not be breast feeding and must
             have a negative serum pregnancy test prior to start of dosing if of child-bearing
             potential or must have evidence of non-child-bearing potential by fulfilling one of
             the following criteria at screening: a) Post-menopausal defined as aged more than 50
             years and amenorrhoeic for at least 12 months following cessation of all exogenous
             hormonal treatments, b) have documentation of irreversible surgical sterilisation by
             hysterectomy, bilateral oophorectomy or bilateral salpingectomy but not tubal
             ligation.

        9 Sexually active male patients should be willing to use barrier contraception i.e.,
        condoms. Female partners of male patients should also use a highly effective form of
        contraception if they are of childbearing potential, unless the male patient is abstaining
        from sexual intercourse.

        Exclusion criteria

          1. Treatment with any of the following:

             Any investigational agents, experimental antibody or antibody drug conjugates, or
             study drugs from a previous clinical study within 3-4 weeks of said prior
             investigational agent(s) with regard to the first dose of study treatment on this CSP

             Any other chemotherapy (except hydroxyurea), immunotherapy or anticancer agents within
             2 weeks of the first dose of study treatment

             Any haematopoietic growth factors (e.g., filgrastim [G-CSF] or sargramostim [GM-CSF])
             within 7 days of the first dose of AZD2811 monotherapy or with combination agent(s) or
             pegylated G-CSF (pegfilgrastim) or darbepoetin within 14 days of the first dose of
             study treatment

             Prescription or non-prescription drugs or other products known to be strong
             inhibitors/inducers of CYP3A that cannot be discontinued prior to Day 1 of dosing and
             withheld throughout the study until 2 weeks after the last dose of study drug. Washout
             periods should be a minimum of 5 half-lives depending on the medication.

             Patients who have undergone allogeneic stem cell transplant within 12 months are
             excluded. If allogeneic transplant was >12 months ago, then they are not excluded as
             long as they are off all immunosuppression and have no signs or symptoms of active
             graft versus host disease.

             Major surgery (excluding placement of vascular access) within 4 weeks of the first
             dose of study treatment

          2. With the exception of alopecia, any unresolved toxicities from prior therapy greater
             than CTCAE Grade 1 at the time of starting study treatment .

          3. Presence of, or history of leptomeningeal disease.

          4. As judged by the Investigator, any evidence of: severe or uncontrolled systemic
             diseases (e.g., severe hepatic impairment, interstitial lung disease [bilateral,
             diffuse, parenchymal lung disease]) or other malignancy (like advanced malignant
             hepatic tumours); current unstable or uncompensated respiratory or cardiac conditions;
             or uncontrolled hypertension; history of, or active, bleeding diatheses (e.g.,
             haemophilia or von Willebrand disease); patients with inflammatory bowel disease
             (e.g., Crohn or colitis ulcerosa); uncontrolled active systemic fungal, bacterial,
             viral, or other infection (defined as exhibiting ongoing signs/symptoms related to the
             infection and without improvement, despite appropriate antibiotics or other
             treatment); or IV anti-infective treatment within 2 weeks before first dose of study
             treatment unless either clear evidence would indicate that despite the clinical
             symptoms no infection took place, or just a single dose of IV antibiotics was
             administered followed by oral treatment thereafter.

          5. Any of the following cardiac criteria: a) Congestive heart failure (CHF) per New York
             Heart Association (NYHA) classification > Class II, b) Cardiac ventricular arrhythmias
             requiring anti-arrhythmic therapy, c) Unstable angina or new-onset angina, d) QTcF
             interval >450 ms (for male subjects) or >470 ms (for female subjects) on screening
             ECG.

          6. Active non-infectious skin disease (including rash, dermatitis, or psoriasis, but
             excluding stable plaque psoriasis from the definition of active disease). Patients
             with a rash that is biopsy-proven leukaemia or with pressure ulcers are not excluded.
             Patients with petechiae from thrombocytopenia or patients with drug related rashes
             that are improving are not excluded..

          7. Patients with a known hypersensitivity to azacitidine or mannitol (HMA combination
             patients only).

          8. History of hypersensitivity to active or inactive excipients (e.g., PEG) of any drug
             in the study or drugs with a similar chemical structure or class to those investigated
             in the study.

          9. Known history of infection with human immunodeficiency virus (HIV)

         10. Serologic status reflecting active hepatitis B or C infection:

               1. Subjects who are anti-HBc positive and who are surface antigen negative will need
                  to have a negative PCR result before enrolment. Those who are hepatitis B surface
                  antigen positive or hepatitis B polymerase chain reaction (PCR) positive will be
                  excluded.

               2. Subjects who are hepatitis C antibody positive will need to have a negative PCR
                  result before enrolment. Those who are hepatitis C PCR positive will be excluded.

        Additional exclusion criteria - venetoclax combination

          1. Adults with previously untreated diagnosis of AML (bone marrow blasts ≥ 20%), UNLESS
             they fulfil inclusion criterion 1(a) above.

          2. WBC count > 25,000 cells/mm3 (25 x 109/L); use of leukapheresis or hydroxyurea before
             venetoclax initiation is allowed to achieve this entry criterion (leukapheresis or
             hydroxyurea must be stopped at least 48 hours before the initiation of venetoclax).

          3. AML with known active central nervous system involvement.

          4. Chronic respiratory disease that requires continuous oxygen use.

          5. Previous venetoclax exposure that ended due to venetoclax toxicity.

          6. Use of moderate CYP3A inhibitor/inducers and P-gP inhibitors, with the exception of
             fluconazole and isavuconazole, that cannot be discontinued prior to Day 1 of dosing.
             Washout periods should be a minimum of 5 half-lives depending on the medication unless
             agreed upon with the Sponsor.

          7. Patient consumed grapefruit, grapefruit products, Seville oranges (including
             marmalades containing Seville oranges) or star fruit within 3 days before the
             initiation of venetoclax.