RIT: an exciting new treatment for acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a blood-borne cancer that has responded extremely well to radioimmunotherapy in clinical and non-clinical trials. Most studies targeted the protein CD33 which is found in high amounts on the surface of most AML cells. The antibody, M195, recognises and binds to CD33. In a research study, M195 was joined to a radioactive agent and used to treat AML patients. Within one hour of administration, the radioactively labelled antibodies had found and bound to the leukaemia cells, showing an extremely powerful anti-cancer effect as more than 99% of the leukaemia cells were killed.

Usually, the only hope for patients with recurrent or unresponsive (to chemotherapy) leukaemias is an allogeneic bone marrow transplant (BMT), involving bone marrow cells being taken from a donor and transplanted into the patient; however, this only results in a 20-25% cure rate. In an attempt to increase the cure rate, scientists have tested the effects of adding radioactive antibodies to the normal pre-transplant treatment routine; usually involving chemotherapy drugs. The reason cancer treatments are given before a bone marrow transplant is to kill as many of the cancerous blood cells as possible before the new, healthy blood cells are transplanted into the patient, this reduces the risk of the cancer returning. One study produced outstanding cure rates of 93% following the bone marrow transplant.

For more information on bone marrow transplants visit the National Cancer Institute:
http://www.cancer.gov/cancertopics/factsheet/Therapy/bone-marrow-transplant