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‘Tailored' prostate cancer treatment can give men extra time
Men with incurable prostate cancer could be given precious extra time by tailored immunotherapy.
Scientists have said a new drug combination has had an 'extraordinary' effect on some patients with no other hope, keeping the disease at bay for more than four years.
The Neptunes trial found that the drug cocktail could extend life when conventional hormone therapies have stopped working, shrinking tumours when given to the right patients.
Hormone-based drugs that block the production of testosterone, slowing or halting the growth of tumours, have become a front-line treatment for many men with metastatic prostate cancer that has spread to other organs.
However, the cancer eventually becomes resistant and finds a path to keep spreading.
The Telegraph is campaigning for the introduction of targeted prostate cancer screening to boost early diagnosis.
A late diagnosis of the disease has been linked to a far worse survival rate. Men diagnosed at an early stage have five-year survival rates of almost 100 per cent, compared to rates of around 50 per cent once it has spread beyond the prostate.
Dr Gianmarco Leone, an oncology researcher from the UCL Cancer Institute and the study's lead author, said the trial's findings were particularly promising because the 74 patients enrolled all had advanced cancer and limited options.
He said: 'With the standard options, the time that these patients could still benefit from treatment was measured in months, definitely not years. But for a small group of patients, we've seen these extraordinary responses where we were able to achieve long-term benefits.'
Previous attempts to use immunotherapy to treat prostate cancer have been largely unsuccessful, with less than 10 per cent of patients responding to the drugs in trials.
Compared with other cancers, many prostate tumours are 'immune-cold', which means they either cannot be recognised by the immune system or have a physical or chemical barrier that repels immune cells.
But the new research discovered that certain sub-populations of patients with advanced prostate cancer can be exceptions to the rule.
The trial by oncologists at University College London Hospitals (UCLH) examined the effect of a combination of immunotherapy drugs – nivolumab and ipilimumab.
Some 70 per cent of patients whose tumours have 'mismatch repair deficiency' – which have up to 20 times as many DNA mutations as other tumours – responded to immunotherapy, delaying disease progression by an average of 10 months.
In men with prostate cancer caused by the BRCA2 gene, which is better known for its link to breast cancer, 50 per cent responded to the drugs and subsequently went into remission for an average of 17 months.
Among men with a high concentration of immune cells around the tumour, 43 per cent had a positive response to the treatment.
As a result, a handful of participants were able to fend off the disease's progression for more than four years.
Dr Mark Linch, a senior author of the study and consultant oncologist at UCLH, said the results pointed towards more personalised approaches tailored to an individual's tumours being the future of advanced cancer treatment.
He said: 'I've been pushing this personalised approach, as unfortunately despite my advice, over the years, the pharmaceutical companies have tended to run very large trials in unselected populations [of prostate cancer patients].
'And while that's been a winner for lung cancers, melanomas and other tumour types, it's not worked for prostate cancer. So this was our effort to test a new strategy.'
Other scientists said they were particularly excited by the response rate in metastatic prostate cancer patients with mismatch repair deficiency.
Nick James, a professor of prostate and bladder cancer research at The Institute of Cancer Research, London, said far more men should be tested in case they have mismatch repair deficiency and could benefit from the new treatment.
Prof James said: 'This testing is not something that's done very much. So there are probably some patients who might benefit, who we're not testing and therefore never get this treatment.'
However, current statistics have shown that mismatch repair deficiency is only present in around 2 per cent of patients, while BRCA gene mutations occur in less than 10 per cent.
Although the Neptunes trial included 74 patients, other experts said they were keen to see the approach tested in a larger study of hundreds of patients with such sub-types of advanced prostate cancer.
They added that trials could combine it with hormone therapy to see if a dual approach would improve response rates even further.
Prof Prasanna Sooriakumaran, a professor of urology at the University of Oxford, said: 'It's really promising because prostate cancer was not previously thought to be very immunogenic.'
'Now we should see whether immunotherapy can have a synergistic effect with the proven treatments which are known to work.'
