Two men with advanced and inoperable prostate cancer have made dramatic recoveries after being treated with an experimental antibody drug.
Rodger Nelson and Fructuoso Solano-Revuelta are now both cancer-free and have returned to normal life.
They were taking part in the trial of drug called ipilimumab that boosts the immune system.
Before treatment at the Mayo Clinic in Rochester, Minnesota, US, each of them had aggressive tumours that had grown well beyond the prostate gland into abdominal areas.
Trial leader Dr Eugene Kwon said: ‘The goal of the study was to see if we could modestly improve upon current treatments for advanced prostate cancer.
‘The candidates for this study were people who didn’t have a lot of other options. However, we were startled to see responses that far exceeded any of our expectations.’
First, the patients received traditional hormone therapy to remove testosterone, which fuels prostate cancer.
Researchers then introduced a single dose of ipilimumab. The drug is an antibody which builds on the hormone therapy and boosts the immune system’s response to the cancer.
Both patients saw their prostate specific antigen (PSA) levels drop to the point where they became eligible for surgery. PSA is a protein in the blood that allows doctors to monitor prostate cancer.
When the surgeons made their incisions, they had a surprise.
Mayo clinic urologist Dr Michael Blute said: ‘The tumours had shrunk dramatically.
I had never seen anything like this before. I had a hard time finding the cancer. At one point the pathologist asked if we were sending him samples from the same patient.’
One patient underwent radiation treatment after surgery.
Further research is planned to understand more about the mechanisms of the antibody and how best to use it on patients.
Dr Kwon said: ‘This is one of the holy grails of prostate cancer research. We’ve been looking for this for years.’
John Neate, chief executive of The Prostate Cancer Charity, said: ‘The reported results of the experimental treatment of these two patients showed dramatic shrinkage of the tumour, allowing surgery to take place.
‘If these early and small-scale results are replicated in larger trials, this represents a potentially very exciting development.
‘We urgently need a wider range of treatment options for prostate cancer which has spread outside the prostate gland and this research is a welcome indication of potential progress in this area.
‘It must be remembered that this is a small trial, however, and the findings are preliminary results.
‘The Prostate Cancer Charity eagerly awaits further research and looks forward with anticipation to exploring the results.’
Meanwhile researchers have claimed that green tea may help slow the advance of prostate cancer.
Men with the disease who consumed the active ingredients found in green tea had lower levels of markers that predict its progress, a U.S. study found.
It involved the use of Polyphenon E, a supplement containing green tea’s active compounds which is under investigation in a number of clinical trials.
Researcher Dr James Cardelli of the Feist-Weiller Cancer Centre, Louisiana, said: ‘It may have the potential to lower the incidence and slow the progression of prostate cancer.’
Prostate cancer affects around 35,000 men in the UK each year and claims some 10,000 lives.
Green tea differs from black tea in that it is not fermented before drying.
This fermentation process appears to reduce the content of flavonoids – beneficial antioxidants – by up to 90 per cent.
Recent studies have shown that green tea may be beneficial for the arteries, lowers ‘bad’ cholesterol and blood pressure, and reduces harmful liver enzymes.
Drinking green tea could help stave off cancer, with a study showing just four cups of green tea a day reverses cell damage in heavy smokers that might lead to the development of tumours.
The American study included 26 men, aged 41 to 72 years, diagnosed with prostate cancer and about to have surgery.
They took a daily dose of Polyphenon E, equivalent to about 12 cups of normally brewed concentrated green tea, for around a month on average.
Findings showed a significant reduction in scores of PSA (prostate specific antigen), a protein marker used to chart progress of the disease, and two other biomarkers. Some patients had reductions of more than 30 per cent.
There were few side effects, says a report in Cancer Prevention Research journal.
It follows a year-long trial in Italy which showed that drinking green tea cut the risk in men with pre-cancerous signs of the disease.
The active ingredients include polyphenols, which have antioxidant properties believed to protect against cell damage.