The primary goal of high-dose chemotherapy (HDC) is to kill as many tumor cells as possible. However, since this intensive chemotherapy results in immune system ablation and bone marrow failure, allogeneic or autologous hematopoietic stem cells are transplanted into the patient to restore the immune system. These transplanted cells can also have a graft-versus- tumor (GVT) effect, as well as repopulating the bone marrow. Nonmyeloablative (NMA) transplantation is a reduced-intensity chemotherapy regimen that utilizes lower doses of anticancer drugs and, which relies largely or solely on GVT effects rather than HDC to eliminate the malignant cells. NMA regimens have been investigated primarily for older and/or less medically fit patients who might not be able to tolerate conventional HDC.