Inclusion Criteria:

• Patients must have a diagnosis of one of the following:

  • relapsed or refractory AML or ALL that has failed to respond to standard therapy, has progressed despite standard therapy
  • relapsed or refractory Myelodysplastic Syndromes
  • previously untreated AML or Myelodysplastic Syndromes in patients > 60 years of age who refused or are not candidates for induction chemotherapy
• Patients with relapsed or refractory CML that has failed to respond to Imatinib therapy or standard therapy, has progressed despite standard therapy, or for which no standard therapy exists
• ECOG performance status of 0, 1, or 2
• Age ≥ 18 years
• Patients or their legal representative must be able to read, understand, and sign a written informed consent (approved by the IRB/EC) prior to study entry

Exclusion Criteria:

• Patients with a history of another cancer other than basal cell carcinoma or cervical intraepithelial neoplasia
• Pregnant or lactating women
• Patients and their partners, if either are of childbearing potential, not using adequate birth control measures throughout the study and for 90 days following the last dose of study medication
• Patients with known meningeal metastasis(es)
• Patients with active or uncontrolled infections, or with a fever >38.5 C
• Patients with serious illnesses, medical conditions, or other medical history, which would be likely to interfere with a patient's participation in the study
• Patients who have been treated with any investigational drug or anti-cancer therapy within 30 days of study start.