Bone marrow is a substance found in the spaces in the center of the larger bones in your body – your hip, breastbone, and pelvis. Bone marrow contains a large number of stem cells, which produce various types of blood cells The initial step of the bone marrow transplant process is called conditioning, in which existing bone marrow cells, including some leukemia cells, are destroyed. This allows the donor’s stem cells to take hold in the patient’s bone marrow, kill the remaining leukemia cells, and replaces unhealthy bone marrow and blood cells with healthy marrow and cells. Bone marrow transplant is considered to be potentially curative for Acute Myeloid Leukemia (AML) including for relapsed or refractory AML. The SIERRA clinical trial seeks to determine the effectiveness of the investigational drug Iomab-B, which may enable more transplants in patients age 55 and older. The SIERRA clinical trial may help improve the way AML is treated in the future.