T-cell therapies harness power of body’s own immune system to offer new hope to cancer patients

Scientists at the Fred Hutchinson Cancer Research Centre in Seattle say they are seeing dramatic outcomes with a new kind of T-cell therapy for patients with tumours that are resistant to conventional high-dose chemotherapy.

Oncologists live in hope of finding cancer treatments that are targeted, do not cause collateral damage and leave the patient immune to their cancer. Now a new form of treatment that harnesses the power of the body’s natural immune system is promising to be all that – and more.

By using a patient’s own T-cells – a type of white blood cell – to attack metastatic tumours that have spread, scientists have been able to achieve astonishing results with patients with advanced blood cancers who had a life expectancy of no longer than five months. These patients were not only in complete remission after 18 months but the cancer also did not return.

It has been reported that the results of the clinical trials will be published later this year and summary results were discussed at the American Association for the Advancement of Science in Washington DC in February 2016.

It was pointed out that while the results were extremely positive, the research was still in an early stage and did not work for all patients. Some patients experienced adverse reactions and died. But it is possible to achieve improvements with patients who have been unsuccessful with other treatments.

Haematologist and ICON member, Jackie Thomson says T-cell therapy may be exactly what oncologists are looking for in a cancer treatment. “The first girl treated with this therapy has been in remission now for more than five years. Her name is Emily Whitehead and her story is truly inspiring.”

The scientists said in one trial of a patient’s own T-Cells, which were engineered in a laboratory, more than 90% of the 35 patients with acute lymphoblastic leukaemia went into complete remission. In two other clinical trials with 40 patients with either non-Hodgkin’s lymphoma or chronic lymphocyte leukaemia, more than 80% of patients responded favourably to the treatment.

The scientists said it was extremely unusual to get such good response rates from patients with such advanced cancer conditions. Dr Stanely Riddell of the Fred Hutchinson Cancer Research Centre in Seattle told the media that T-cells help to identify invading viruses and bacteria and could keep a “memory” of previous infections to trigger a rapid immune response. He said T-cell therapy worked most effectively on liquid tumours of the blood and bone marrow.

Meantime, research at the Francis Crick Institute in London and reported in the Journal of Science is also pursuing the possibility of such therapies in the treatment of melanoma and lung cancer.

Dr Thomson said she believed T-cell therapy could be used for patients in South Africa. “At present, the T-cells that kill the cancer are harvested from the patients themselves which means they can only be used to treat that patient,” she said. “But I know that certain laboratories have been able to change the T-cell receptor in order for these cells to be given to any patient and these products will then be mass produced and available on the market for any patient anywhere in the world.”

In terms of the cost of such treatment, Dr Thomson said she believed it would become more affordable once the research had been done and the cells had been created.

“What is incredible about this therapy is that patients will have immunity against their cancer cells. It is the same concept as with a vaccination, which provides immunity against a virus and needs to be given only once.”

She said the fact that some patients had not reacted well to the T-cell treatment was not a cause for concern as researchers were already working on creating cells that would bind to more than one target and that this would reduce resistance. An antidote for the inflammatory response after cell injection had also been developed.

“I am really excited about the great strides researchers have made with T-cell therapy and the possibilities for oncologists,” she says.