Inclusion Criteria:

- Patients with cytopathologically confirmed diagnosis of AML according to WHO
criteria, excluding acute promyelocytic leukemia.

- First relapsed AML

- Primary refractory AML defined as failure to respond to initial induction
chemotherapy (no CR) or recurrence within 6 months of initial CR.

- Age more than 18 years

- ECOG performance status < 2

Exclusion Criteria:

- Prior treatment with deacetylase inhibitor

- Concurrent therapy with any other investigational agent

- Patients who have received cumulative doses (or its equivalent to other
anthracyclines) of more than 360 mg/m2 of doxorubicin will be excluded from the
study.

- Clinical symptoms suggesting CNS leukemia

- LVEF below 45% Other protocol-defined inclusion/exclusion criteria may apply