A latest study revealed that a group of advanced leukaemia and pre-leukaemia patients, who earlier had no curative options, were successfully treated with a combination of antibody and stem cell transplantation.
A clinical trial conducted by Fred Hutchinson Cancer Research Centre on 58 patients with a median age of 63 and all with advanced acute myeloid leukaemia or high-risk myelodysplastic syndrome – a pre-leukemic condition, saw blood cancers go into remission using a combination of targeted low intensity chemotherapy delivered by an antibody and stem cell transplant. The outcome showed that forty percent of patients survived even after a year of treatment and another thirty five percent for three years. This group showed the same survival rates as those who received the same treatment but were already in remission at the time of therapy.
Headed by John Pagel, M.D., Ph.D, a transplant oncologist and assistant member of the Hutchinson Centre’s Clinical Research Division, this study’s original aim was to measure the maximum acceptable amounts of radiation that can be given as a part of therapy without causing toxic effects. Of all the patients participating in this trial, 86% had active disease and only 10% were in remission. Their cancers had failed previous treatment methods and had few or no other existing options for a potential cure. According to Pagel, “It is fair to say that these patients would likely have died without a transplant being performed if they had not been given the opportunity to participate in this study.”
The procedure of the study involved giving a radiation of 26 gray starting from 12 gray, escalating the dosage in increments of 2 gray. At 26 gray, toxic effects to heart and lungs were found, thereby concluding the maximum effective dosage to be 24 gray. Radiation is delivered intravenously by using a radio labelled antibody that has therapeutic Iodine 131, designed to attack leukemic blood cells.
Due to targeted radiation that is possible through this method as against standard external radiation beam, there is a two to four fold increase in the amount of radiation reaching cancerous cells, without radiating to surrounding normal tissues and cells. The greater the amount of radiation, the more the number of cancer cells destroyed in preparation for transplanted stem cells to take over the diseased immune system and killing the remaining cancer cells.
Pagel said further research is needed to test more patients at the highest radiation dose both at the Hutchinson Centre and at other transplant centres around the country.
This research is supported by grants from the National Institutes of Health, the Leukaemia and Lymphoma Society of America, the Damon Runyon Cancer Research Foundation, the Edson Foundation and the Frederick Kullman Memorial Fund.