Decitabine for Older or Unfit Patients With Acute Myeloid Leukemia (AML)

Study Groups: If you are found to be eligible to take part in this study, you will be assigned to 1 of 2 dose levels of decitabine based on when you join this study. If you are among the first 20 participants, you will have an equal chance of being in either group. If you enroll after that, you will have an increasingly higher chance (51-100%) of being assigned to the group that had better results, depending on how much better that treatment arm is. Study Drug Administration: Each cycle is about 4-8 weeks, depending on the doctor's decision. In this study you will receive induction therapy to try to control the disease and cause remission (this is when tests and/or the doctor cannot find signs of the disease). If you are in Group 1, you will receive decitabine by vein over about 1 hour for 5 days. If you are in Group 2, you will receive decitabine by vein over about 1 hour for 10 days. If the disease is in remission, you may receive more cycles (called maintenance) to help keep the disease under control. If you are in Group 2, you will receive 5 day dosing during maintenance, or when the doctor thinks it is in your best interest. Your dose schedule or dose level may be changed if the doctor feels it is in your best interest. Study Visits: The following tests and procedures will be performed: * Blood (about 2-3 teaspoons) will be drawn 1-2 times weekly for first cycle, then every 2-4 weeks after that. After the 6th cycle or sooner if the doctor decides, this blood draw will be performed only 1 time per cycle. * Every 1-3 cycles, you will have a bone marrow aspiration/biopsy to check the status of the disease. Blood (about 2-3 teaspoons) may also be drawn for genetic testing if the disease is in remission and the doctor thinks it is needed. Length of Treatment: You may continue taking the study drug for as long as the doctor thinks it is in your best interest. You will no longer be able to take the study drug if the disease gets worse, if intolerable side effects occur, or if you are unable to follow study directions. Your participation in this study will be over after the follow-up phone calls. Follow-Up: After you stop the study treatment, you will be called by phone twice a year and asked how you are feeling. The phone calls should last about 5 minutes each time. This is an investigational study. Decitabine is FDA approved and commercially available for the treatment of myelodysplastic syndrome (MDS). Its use to treat AML is investigational. Up to 100 participants will be enrolled in this study. All will take part at MD Anderson.