Terminated by Sponsor

The purpose of this study is to evaluate the efficacy and safety of decitabine when used before chemotherapy to treat leukemia in pediatric patients. The study will also evaluate the ways decitabine is affected or changed when used in the human body.

Inclusion Criteria:

1. Males and females, age 1 to16 years, inclusive
2. Females of childbearing potential must have a negative serum beta human chorionic gonadotropin (β-hCG) at Visit 1 (Screening) and a negative urine pregnancy test prior to starting study drugs (Visit 2). Female subjects of childbearing potential must agree to be abstinent or to use a highly effective method of contraception (eg, condom + spermicide, condom + diaphragm with spermicide, intrauterine devise (IUD), or have a vasectomised partner) for at least one menstrual cycle prior to starting study drug(s) and throughout the longer of either Core Study period or 30 days after the last dose of study drug. Those females using hormonal contraceptives must also be using an additional approved method of contraception (as described previously).
3. Sexually mature male patients who are not abstinent or have not undergone a successful vasectomy, who are partners of women of childbearing potential must use, or their partners must use a highly effective method of contraception (eg, condom + spermicide, condom + diaphragm with spermicide, IUD) starting for at least one menstrual cycle prior to starting study drug(s) and throughout the entire study period and for 30 days (longer if appropriate) after the last dose of study drug. Those with partners using hormonal contraceptives must also be using an additional approved method of contraception (as described previously).
4. Diagnosis of acute myelogenous leukemia (AML)(bone marrow or peripheral blood blasts ≥ 20%)
5. Adequate cardiac function as defined by an echocardiogram or multiple gated acquisition (MUGA) scan demonstrating an ejection fraction within normal limits
6. Are willing and able to comply with all aspects of the protocol
7. Provide written informed consent from subject's guardian or legally authorized representative and child assent (if applicable)

Exclusion Criteria:

1. Females who are pregnant (positive β-hCG test) or lactating
2. History of chronic myelogenous leukemia (CML) [t(9;22)]
3. Acute promyelocytic leukemia (M3 subtype in French-American-British [FAB] classification).
4. Known central nervous system (CNS) leukemia
5. AML associated with congenital syndromes such as Down syndrome, Fanconi anemia, Bloom syndrome, Kostmann syndrome, or Diamond Blackfan anemia
6. White blood cell (WBC) count > 40,000/mm3
7. Serum creatinine > 2.5 mg/dL
8. Alanine aminotransferase (ALT) > 5 x upper limit of normal (ULN) and/or total bilirubin > 3 x ULN
9. Prior chemotherapy (other than hydroxyurea) or radiation therapy for AML
10. Known to be human immunodeficiency virus (HIV) positive
11. Any history of or concomitant medical condition that, in the opinion of the Investigator, would compromise the subject's ability to safely complete the study
12. The Investigator believes the subject to be medically unfit to receive the study drug or unsuitable for any other reason.
13. Subject with hypersensitivity to decitabine, daunorubicin, or cytarabine
14. Has participated in a drug trial in the last 4 weeks