Inclusion Criteria:

Phase l:

- Patients with cytopathologically confirmed diagnosis of AML according to WHO
criteria, excluding acute promyelocytic leukemia who are eligible for Vidaza
treatment

- ECOG performance status greater less than or equal to 2

Phase ll:

- Adult patients (age ≥ 18 years) who are candidates for treatment with 5-Aza and
present with one of the following:

- intermediate-2 or high-risk myelodysplastic syndromes according to the
International Prognostic Scoring System (IPSS). OR

- AML with multilineage dysplasia and maximum of 30% blasts (former RAEB-T
according to FAB) OR

- chronic myelomonocytic leukemia (CMML)

- Patients must have the following laboratory values unless elevations are considered
due to MDS or leukemia: AST/SGOT and/or ALT/SGPT ≤ 2.5 x ULN; serum creatinine ≤ 1.5
x ULN; serum bilirubin (total and direct) ≤ 2 x ULN; electrolyte panel within normal
ranges (WNL) for the institution.

Exclusion Criteria:

Phase l:

- Prior treatment with deacetylase inhibitors

- Concurrent therapy with any other investigational agent

Phase ll:

- Planned hematopoietic stem-cell transplantation (HSCT)

- Patients with therapy-related MDS

- Patients with therapy-related AML and/or relapsed/refractory AML

- Patients with impaired cardiac function including any of the following:

- Complete left bundle branch block or use of a permanent cardiac pacemaker,
congenital long QT syndrome, history or presence of ventricular tachyarrhythmia,
clinically significant resting bradycardia (<50 beats per minute), QTcF > 460 ms
on screening ECG, or right bundle branch block + left anterior hemiblock
(bifascicular block)

- Presence of unstable atrial fibrillation (ventricular response rate >100 bpm).
Patients with stable atrial fibrillation are eligible provided they do not meet
the other cardiac exclusion criteria

- Previous history of angina pectoris or acute MI within 6 months

- Screening LVEF <45% by echocardiography or MUGA

- Other clinically significant heart disease (e.g. uncontrolled hypertension or
history of poor compliance with an antihypertensive regimen).

- Any of concurrent severe and/or uncontrolled medical conditions which could
compromise participation in the study. For example:

- Uncontrolled diabetes

- Active or uncontrolled infection

- Uncontrolled hypothyroidism

- Acute or chronic liver or renal disease

- Patient has evidence of clinically significant mucosal or internal bleeding

Other protocol-defined inclusion/exclusion criteria may apply