A potentially revolutionary cancer therapy has had “extraordinary” results on terminally ill patients in initial tests, according to a new study revealed this week by scientists from the Fred Hutchinson Cancer Research Center in Seattle, US.
In the study, presented at the annual conference of the American Association for the Advancement of Science in Washington, 94 percent of patients suffering from acute lymphoblastic leukemia, which can kill in a matter of months, were cured of all symptoms. Patients with other forms of leukemia had response rates of over 80 percent and over half of these went into complete remission.
Lead scientist Professor Stanley Riddell said that the results were among patients who were projected to have two to five months to live.
He added: “This is extraordinary. This is unprecedented in medicine to be honest, to get response rates in this range in these very advanced patients.”
The technique involves removing immune cells called T-cells from patients, tagging them with “receptor” molecules that target cancer, and putting them back into the body in an infusion.The targeting molecules, known as chimeric antigen receptors or Cars, came from specially bred genetically engineered mice.Once they are attached to the T-cells, they reduce the ability of the cancer to shield itself from the body's natural immune system.
Speaking at the American Association for the Advancement of Science (AAAS) annual meeting in Washington DC, Prof Riddell described the results as a “potential paradigm shift” in cancer treatment.
Much more work was required, he said, adding that it was not clear how long the symptom-free patients would remain in remission.
“This is really a revolution,” said the head of the Experimental Hematology Unit of Milan's San Raffaele University, Chiara Bonini, who has worked on immunotherapy for years. “I haven't seen such high remission rates in clinical trials in over 15 years,” she stated at the conference.
Prof Riddell hopes to try the therapy on patients suffering from cancers with solid tumors, but said they would present different challenges. Although the body's natural immune system is geared to tackle cancer, it is often unable to. Sometimes, the body's defences cannot recognize cancer cells or find ingenious ways to mask their identity.
In the most promising of Prof Riddell's studies, around 35 patients with acute lymphoblastic leukaemia (ALL) were treated with the modified cells.
Almost all – 94% – went into complete remission. Being in remission is not the same as saying they are cured, because the symptoms can return.
Other medics are urging caution. Dr Yvonne Doyle, from Public Health England, said: “It's an important breakthrough, in that it's a new technology that seems to have developed something innovative.
“However, it is on 30 patients who are at a very advanced stage of a particular cancer. So what we need to know is – does this work in a wider situation?”
The treatment is similar to a technique used with success last year on Layla Richards, a one-year-old girl with ALL, by doctors at Great Ormond Street Hospital, London who described the results as “staggering“.
Yet one immunologist who treated Layla, Professor Waseem Qasim, said it was still early days to view this treatment as a cure for all cancers: “We will have to wait and see how these type of treatments play out for solid cancers such as cancers of the lung or the bowel or the breast and so on…
“The first portion of investigations and successes I think will be in the blood-type cancers.”