• Maximum tolerated dose (MTD) [ Time Frame: Following each treatment cycle every 4 weeks ] [ Designated as safety issue: Yes ]
  

Clofarabine is a new chemotherapy drug that is designed to interfere with the growth and development of cancer cells.

Before you can start treatment on the study, you will have what are called "screening tests". These tests will help the doctor decide if you are eligible to take part in the study. You will have a complete medical history and physical examination. You will also be asked about what medications you are taking currently and about the level of your daily activities. Routine blood tests (about 2 tablespoons) will be done within 14 days before the start of the study to make sure that you are not at increased risk for developing side effects.

You may have bone marrow samples collected. To collect a bone marrow sample, an area of the hip or chest bone is numbed with anesthetic and a small amount of bone marrow is withdrawn through a large needle.

If you are found to be eligible, you will receive clofarabine as a 1-hour infusion into a vein once once every 2 weeks for 4 weeks. This cycle makes up one treatment course.

The drug is evaluated at different dose levels. The first three patients will start with a lower dose. Unless serious side effects occur, the next group of patients (usually groups are 3 patients, although they can be expanded to include more patients if needed) will receive a higher dose.

If you show a response and do not experience any severe side effects, you can receive up to a total of 6 courses of therapy. During each course, clofarabine is given the same way as during the first course. However, the dose of clofarabine may be lowered during later courses to decrease the risk of side effects that may have occurred in previous courses. If the disease gets worse or you experience any intolerable side effects, you will be taken off the study and your doctor will discuss other treatment options with you.

Before every treatment course, your doctor will perform a physical exam, including measurement of your weight and vital signs. You will be asked about the level of your daily activities and how you are feeling. At least once every two weeks (more often if your doctor feels it is necessary), you will have blood samples (about 1-2 teaspoons) collected for routine lab tests. Repeat bone marrows will be collected after the third and sixth course. However, if you complete the study before the third course, the bone marrow may be taken then. No bone marrow may be taken if the condition of your disease is obvious from the blood.

You will need to stay in Houston for the first 4 weeks of treatment. After that, you may return to your home but you will still have to return to Houston to receive the clofarabine treatment. You may choose to have check-up visits and blood tests with your local doctor.

After you finished your treatment, and as long you are participating on this study, you will be scheduled every 3-6 months to check on the status of the disease and your overall health.

This is an investigational study. Clofarabine is authorized by the FDA for use in research only. Up to 36 participants will take part in this study. All will be enrolled at M. D. Anderson.