Patients with terminal cancer could "effectively be cured" by the discovery of a pair of drugs which can shrink tumours or bring them under control in nearly 60% of people with advanced melanoma.
In an international trial of 945 patients, treatment with the drugs ipilimumab and nivolumab stopped the cancer advancing for nearly a year in 58% of cases. This was compared with 19% of cases for ipilimumab alone, which resulted in tumours stabilising or shrinking for an average of two and a half months.
The treatment, known as immunotherapy, uses the body's immune system to attack cancerous cells. Researchers say it could replace chemotherapy as the standard treatment for cancer within five years.
The findings, revealed at the at the American Society of Clinical Oncology, and published in the New England Journal of Medicine, could save tens of thousands of lives in the UK alone within a decade, doctors say. Patients who could expect to live for just a matter of months under existing treatments, could see their tumours completely destroyed and go on to enjoy a normal lifespan under the new treatment.
A series of studies show that the drugs are effective against some of the most deadly tumours, including those of the lung, bowel, liver and head.
Roy Herbst , chief of medical oncology at Yale Cancer Centre, described the results as "spectacular". "I think it's huge," he said. "I think we are seeing a paradigm shift in the way oncology is being treated.
"The potential for long-term survival, effective cure, is definitely there," he added.
Dr James Larkin, a consultant at the Royal Marsden hospital and one of the UK's lead investigators, explained to the BBC how the treatment works. "By giving these drugs together you are effectively taking two brakes off the immune system rather than one, so the immune system is able to recognise tumours it wasn't previously recognising and react to that and destroy them."
But other experts have urged caution over the new findings. Oncologist Prof Karol Sikora, the dean of the University of Buckingham's medical school, told the BBC Radio 4 Today programme that there is a long way to go before doctors are in possession of a miracle cure.
"The current discoveries being released in Chicago, the media pick them up and for cancer patients it's very sad. You would think cancer was being cured tomorrow. It's not the case. We've got a lot to learn."
"The prolongation of survival from these very expensive immune therapies is often a matter of weeks or months and we've got to make it long-lasting and that has to be our priority," she continued.
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