This research study is for patients with acute myeloid leukemia (AML) that do not see improvement in their condition with the usual chemotherapy, and who have decided with their doctor to continue treatment with a stem cell transplant. Normal preparation for a stem cell transplant includes pre-treatments that help the body accept donor cells. This is a process called conditioning. The purpose of this study is to understand how both AML and the body respond when a chemotherapy medication called clofarabine is given in the days before the transplanted donor stem cells are received. The researchers will study whether this experimental treatment improves how well the stem cell transplant works when it is used in combination with the usual pre-transplant conditioning.

You will participate in a screening period, a conditioning treatment period that includes the study medication clofarabine and follow up evaluations and assessments. If you agree to participate, the research team will evaluate you to see if you are able (eligible) to take part in this study and receive the clofarabine medication. This is called a “study screening.” If you are eligible for the study, the study medication clofarabine will be given once a day for 5 days (total) starting 14 days before your transplant infusion. After you have received all 5 doses and depending on your health status, you will have rest for about 3 days. A conditioning treatment consisting of chemotherapy and total body irradiation (TBI) will be given during the 5 days prior to receiving your transplant. If you are less than 55 years old, your doctor will decide if you will receive chemotherapy medications called fludarabine and busulfan (Regimen A). You will receive a weaker conditioning regimen to include fludarabine and cyclophosphamide if you are more than 55 years old, have had prior allogenic transplant, or are not able to receive the intense regimen (Regimen B). You will receive TBI in preparation for your transplant procedure. The purpose of conditioning treatment is to prepare your body to accept and not reject your donor’s cells (the infusion). Conditioning can also help to destroy any remaining cancer cells you may have in your body. You will be consented for individual transplant conditioning regimen separately in addition to the research consent. After completing your conditioning treatment, you will receive your transplant. Following your transplant procedure, you will receive the following three medications to help prevent the side effect of GVHD: cyclophosphamide, tacrolimus, and mycophenolate mofetil. About 5 days after you receive your transplant infusion, you will be begin a medication called granulocyte colony stimulating factor or G-CSF (also called Neupogen). G-CSF is a naturally occurring special protein in the body that stimulates (pushes) blood cell production and growth. This medication will help to increase the number of donor stem cells in your body. Treatment with this medication will continue until engraftment. Engraftment is defined as the time that the donor cells are accepted by your body and begin to work.