Inclusion Criteria:

• Patients who have a diagnosis of acute myeloid leukemia that is relapsed or refractory to a least 1 prior treatment for leukemia, or patients with chronic myeloid leukemia (CML) who are in myeloid blast crisis which have failed at least 1 previous tyrosine kinase inhibitor (TK1). A baseline bone marrow assessment is required less than or equal to 96 hours prior to the first dose of study drug.
• Must have discontinued all previous therapies for cancer, including chemotherapy, radiotherapy, immunotherapy, cancer related hormone therapy, or other investigational therapy for at least 21 days for myelosuppressive agents (such as cytarabine, daunorubicin, and gemtuzumab ozogamicin) or 14 days for non-myelosuppressive agents prior to receiving study drug, and recovered from the acute effects of therapy (such as neurotoxicity, diarrhea, and mucositis) except for residual myelosuppression and alopecia. Hydroxyurea is permitted to control the peripheral blast cell count, but must be stopped at least 24 hours before study drug administration. administration.
• Must have adequate organ function.
• Females must have a negative pregnancy test. Male and female patients must agree to use a reliable method of birth control during and for 6 months following the last dose of study drug.
• Patients must be at least 18 years old.

Exclusion Criteria:

• Have received treatment within the last 30 days with a drug that has not received regulatory approval for any indication within 14 or 21 days of the initial dose of study drug for a non-myelosuppressive or myelosuppressive agent, respectively.
• Patients with acute promyelocytic leukemia (APML).
• Major surgery within 4 weeks of study enrollment.
• Patients with serious pre-existing medical conditions (at the discretion of the investigator). Because of the known cardiac toxicity of anthra- cyclines, patients with pre-existing ejection fraction (EF) less than or equal to 45% should not participate in this study. No patient should exceed the maximum exposure of anthracycline doses (for example, idarubicin greater than 120mg/m2).
• Patients with a second malignancy that could affect the interpretation of the results.
• Patients with leukemic involvement of the CNS by spinal fluid cytology or imaging.
• Patients with known coagulopathy or bleeding disorder, other than leukemia related thrombocytopenia. Patients with severe of life threatening bleeding refractory to platelet transfusions are also excluded.
• Concomitant anticoagulant therapy (with the exception of heparinized saline to maintain the patency of central venous catheters).
• Women who are pregnant or breast feeding.
• Patients with a known hypersensitivity to oligonucleotides, idarubicin, and/or cytarabine.