Inclusion Criteria:

- Adults with Acute Myeloid Leukaemia in first relapse (except Acute Promyelocytic
Leukaemia (APL) who are deemed ineligible for intensive chemotherapy on the grounds
of age or co-morbidities

- Patients must have achieved a previous morphological CR as defined by Cheson criteria
after treatment with myelosuppressive chemotherapy

- Patients are able to receive treatment as out-patient

- Adequate renal and hepatic function as defined in the Protocol

- Patients have given written informed consent

- ECOG performance status less than or equal to 2

Exclusion Criteria:

- Patients with greater than class III NYHA cardiac impairment

- Blastic transformation of Chronic Myeloid Leukaemia

- Prior allogeneic/autologous haematopoietic stem cell transplant

- Pregnant or lactating women

- Adults of reproductive potential not willing to use appropriate, effective,
contraception during the trial and for specified amount of time afterwards

- Patients who have received prior histone deacetylase inhibitor (HDACi) treatment as
anti-tumour therapy. (Patients who have received HDACi treatment for other
indications e.g valproic acid for epilepsy may enrol after a 30-day washout period)

- Previous anti-tumour therapies, including prior experimental agents or approved
anti-tumour small molecules and biologics, within 30 days before the start of
protocol treatment

- Patients who have received prior treatment with demethylating agents such as
5-azacitidine or decitabine

- Patients with contraindications to receiving azacitidine or vorinostat such as
hypersensitivity, patients unable to have a subcutaneous injection or swallow oral
capsules

- Active symptomatic fungal, bacterial, and/or viral infection including known active
HIV or known viral (A, B, or C) hepatitis

- Any co-morbidity that could limit compliance with the trial