US:THE CANCER research community remains in shock following the announcement that a patient with a form of advanced and almost certainly fatal skin cancer has been completely cleared of the disease.
The man had developed secondary cancers of the lung and lymph nodes, yet the experimental treatment helped him to clear the disease and remain free of cancer for the past two years.
News of the treatment came this week in the prestigious New England Journal of Medicine, whose publication of the research report gives it particular credibility.
The most startling aspect of the treatment was that it was based on using one of the 52-year-old's own immune system cells, cloned outside the body and then reintroduced into the patient. More than five billion copies of this cell were produced and when infused back into the patient, managed to clear all traces of the advancing cancer.
The man had developed malignant melanoma, an often fatal form of skin cancer. It spreads or metastasises readily to other locations in the body, making it particularly difficult to treat. The fair-skinned Irish here and also living in sunnier climates as in Australia, are particularly susceptible to this form of skin cancer.
The man had failed to respond to other commonly used treatments such as surgery, radiation and chemotherapy. He then enrolled in an experimental clinical trial at the Fred Hutchinson Cancer Research Center in Seattle, Washington state, in the US.
Dr Cassian Yee and colleagues there had developed a new therapy based on the use of a specific type of immune system cell, a CD4 T "helper" cell. This cell is central to the body's usual antibody-based response to infection in that it helps alert the other immune system cells to the presence of "foreign" bodies such as invading viruses and bacteria.
Once triggered it helps identify the invaders and calls in the deadly natural killer cells and other white blood cells called phagocytes that directly attack and destroy the foreign material.
Cancer cells usually evade this attack given they do not appear "foreign" to the T helper cells and successfully masquerade as "self". Also, there are too few T helper cells circulating in the bloodstream to have much of an effect in cancer treatment.
Dr Yee's research group found and extracted some of the patient's T helper cells and then sensitised them to recognise the cancer cells as foreign. They then cloned these sensitised cells, bulking them up to billions of cells, all ready to recognise the cancer as something to be attacked.
No other preparatory treatments were given, but once introduced, the cells triggered the immune system and cleared the cancer cells within about 60 days. The man remains tumour-free two years after treatment.
"We were surprised by the anti-tumour effect of these CD4 T cells and their duration of response," Dr Yee said.
He warned, however, that while eight patients had so far received the therapy, many more trials were needed to confirm it as a valuable treatment.
"These findings support further clinical studies," he added.
