RIT before a bone marrow transplant in advanced acute leukaemia patients

The best chance of curing a patient with advanced acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS); both being types of blood cancer, is with a bone marrow transplant, although the number of long term survivors after transplant is on average only 30% for both diseases. The high doses of external radiation and chemotherapy usually used to kill leukaemia cells before new, healthy blood cells are transplanted; cause severe side effects, as they damage a lot of normal, healthy cells too. Also, although these cancer treatments are high dose, in many patients who have received a bone marrow transplant, the cancer returns. To reduce the risk of the cancer returning, researchers have investigated using radioimmunotherapy (RIT) to deliver targeted radiation to diseased blood cells, killing them, before receiving new transplanted blood cells. The chosen target was the protein CD45, which is found on most blood cell surfaces. Research has shown that using an antibody recognising the CD45 surface protein was attached to a radioactive molecule, in patients with acute leukaemia, more than 5 times more radiation was delivered to the tissues that make new blood cells, like the bone marrow and spleen, compared to any other organ. This shows how RIT has the ability to deliver very high amounts of radiation that can be targeted to sites of disease, due to the combination of specific antibody and cell damaging effects of radiation, which could potentially reduce the risk of the cancer returning.

For more information see the Fred Hutchinson Cancer Research Centre: http://www.fhcrc.org/