Clofarabine Plus Low-Dose Cytarabine Induction and Decitabine Consolidation in Frontline Acute Myeloid Leukemia (AML) and High-Risk Myelodysplastic Syndrome (MDS)

The goal of this clinical research study is to learn if clofarabine given in combination with cytarabine and decitabine can help to control the disease in patients with AML or MDS who are 60 years old or older. The safety of this treatment will also be studied.

The Study Drugs: Clofarabine is designed to interfere with the growth and development of cancer cells. Cytarabine is designed to insert itself into DNA (the genetic material of cells) of cancer cells and stop the DNA from repairing itself. Decitabine is designed to damage the DNA of cells, which may cause cancer cells to die. Study Drug Administration: If you are found eligible to take part in this study, on Days 1-5, you will receive clofarabine through a needle in your vein over 1-2 hours. On Days 1-10, you will receive cytarabine by injection twice a day. You may receive up to 2 cycles at this dose and schedule. There are 10 days in each cycle. Consolidation Cycles: If you show a response to the treatment, you can then continue with up to a total of 17 more cycles of therapy, which will be called "consolidation cycles". Not every participant may be able to receive all 17 consolidation cycles. The actual number that you will receive depends on whether or not you maintain the response and how you are able to tolerate ongoing therapy. There will be 4-7 weeks in between each consolidation cycle depending on any side effects you may be having and your blood counts. For consolidation cycles 1, 2, 6, 7, 8, 12, 13, and 14, you will receive clofarabine and cytarabine, but the schedule will be different. On Days 1-3 you will receive clofarabine by vein. On Days 1-7, you will receive cytarabine by vein. On the days when you receive both clofarabine and cytarabine (Days 1-3), the clofarabine will be given about 3-6 hours before the cytarabine injections. You can be taught to give cytarabine injections to yourself. In this case, you can leave the clinic after receiving clofarabine. You will be required to record the injections of cytarabine in a diary unless you receive the treatments while you are in the hospital. During consolidation cycles 3-5, 9-11, and 15-17, you will receive decitabine only. Decitabine will be given through a needle in your vein over 1-2 hours on Days 1-5. During the decitabine cycles, you may be treated at home, but must return to MD Anderson for study visits before the start of each cycle. If you do not achieve a response after the first 2 cycles of treatment with clofarabine and cytarabine, you can stay on study and receive 3 cycles of decitabine alone (same dose and schedule as the consolidation course). If you achieve a response after the 3 decitabine cycles, you can continue with the consolidation cycles. If there is no evidence of response after the 3 decitabine cycles, you may be taken off study. Study Visits: On Day 1 of every cycle, the following tests and procedures will be performed: * You will have a physical exam, including measurement of your weight and vital signs. * You will have a performance status evaluation. * Blood (about 1-2 teaspoons) will be drawn for routine tests. About 3 weeks after your first course, you may have a bone marrow aspirate to check the status of the disease. To collect a bone marrow aspirate, an area of the hip is numbed with anesthetic, and a small amount of bone marrow is withdrawn through a large needle. After that, you will have a bone marrow aspirate every 2 weeks (or more often if your doctor feels it is necessary). If your routine blood tests indicate that there is still leukemia, you may not need to have the bone marrow samples collected. You will need to stay in Houston for up to the first 5 weeks of treatment. After that, you will need to return to Houston before each cycle and to receive the clofarabine treatments. Decitabine-only consolidation cycles can be given by your local oncologist. In either case, you can have check-up visits and blood tests with your local doctor between treatments. Length of Study: You can stay on study for up to 19 cycles. You will be taken off study early if you experience any intolerable side effects. You may be taken off study early if the disease gets worse. Follow-up Visits: Once you are off active treatment but as long as you are still part of the study, every 3-6 months you will have blood (1 tablespoon) drawn to check the status of the disease and your overall health. This is an investigational study. Clofarabine is FDA approved and commercially available for use in pediatric patients with ALL. Its use in patients with AML is experimental. Cytarabine is FDA approved and commercially available for use in patients with AML. Decitabine is FDA approved and commercially available for use in patients with MDS, but its use for patients with AML is investigational. Up to 120 patients will take part in this study. All will be enrolled at M. D. Anderson.