Thousands of men with advanced prostate cancer could live for longer by taking a ‘precision’ drug, a major trial has suggested.
Lynparza extended the lives of men with an incurable form of the disease, which is resistant to standard treatment.
The medication froze the disease progression by an average of 7.4 months – more than double that of hormone treatment currently used.
Men on the drug, also known as olaparib, lived for 18.5 months – about 3.5 months longer than treatment used on the NHS.
It is the first proven drug for prostate cancer that can be personalised to a patients’ genetic makeup, rather than using a one-size-fits all approach.
Olaparib – already used around the world and on the NHS for ovarian cancer – works by targeting faulty DNA which help cancer cells repair and thrive.
Scientists have said the results were a ‘remarkable achievement’, and could improve the lives of up to 10,000 British men.
Thousands of British men with advanced prostate cancer are set to get the first ‘precision’ drug for their disease. Pictured, prostate cancer cells
Lynparza is intended to treat men whose cancers don’t respond to other therapies. Their cancer continues to grow and spread, which is eventually fatal.
This is called metastatic castration-resistant prostate cancer (mCRPC). Scientists say there is a growing need for new and effective therapies for these patients.
It affects around 10 to 20 per cent of prostate cancer patients within five years of their diagnosis – equal to between 4,000 and 10,000 men per year in the UK.
AstraZeneca, the manufacturer of Lynparza, ran the trial of the drug alongside US pharmaceutical company MSD, or Merck.
WHAT IS THE DRUG?
Lynparza is the branded name of the drug olaparib.
It is a treatment for some people with ovarian cancer, fallopian tube cancer and peritoneal cancer who have a change in a gene called BRCA.
PARP – short for Poly (ADP-ribose) polymerase – is a protein that helps damaged cells to repair themselves. Olaparib stops PARP working.
Some cancer cells rely on PARP to keep their DNA healthy. This includes cancer cells with a change in the BRCA gene.
When olaparib stops PARP from repairing DNA damage, the cancer cells die.
This is a type of targeted cancer drug, called a cancer growth blocker.
Source: Cancer Research UK
The phase three trial of the drug, called PROfound, was led by scientists from the Institute of Cancer Research in London and Northwestern University in Chicago.
They compared Lynparza – the branded name of the drug olaparib – with standard hormone treatments on the NHS, abiraterone and enzalutamide.
Disease progression was halted for 7.39 months in men taking Lynparza, compared to 3.55 months with hormonal treatment.
Men lived for 18.5 years when treated with Lynparza, compared to 15.1 months with hormone treatment.
Treatment with Lynparza resulted in a 66 per cent greater delay in progression than the hormonal agents, the results also showed.
Dr Eleni Efstathiou, MD Anderson Cancer Center, Houston, said: ‘This is impressive because it is considerably higher than the 35-40 per cent improvements with which we’ve been very satisfied in previous prostate cancer studies in this more advanced disease setting.
‘There is a trend towards improved survival, but we need to wait for the final analysis.’
Study author Professor Maha Hussain, Northwestern University, said: ‘To see such a significant effect on disease progression and other clinically relevant effects such as pain progression and objective response rate is a remarkable achievement.
‘We saw the benefits of olaparib in all sub-groups of patients, regardless of country, age, prior therapy and severity of disease, including in those with worse disease that had spread to their liver or lungs.’
Lynparza works by targeting mutated BRCA genes – of which some of the men in the study have.
Men with a broader range of less well studied faulty DNA repair genes were also studied in the trial with similar results.
Cancer cells with a change in their genes rely on a protein called PARP, which helps damaged cells to repair themselves. Lynparza blocks PARP, leading to the cancer cells dying.
Hormonal treatment, on the other hand, lowers testosterone, the male sex hormone, which many prostate tumours thrive off.
When a man is diagnosed with prostate cancer, he may be given surgery, radiotherapy, chemotherapy or hormonal treatment.
But if the cancer spreads to other parts of the body and cannot be cured, treatment is focused on prolonging life and relieving symptoms.
Lynparza may work for men whose cancers have continued to grow and spread even when their testosterone levels are medically reduced.
Professor Hussain said: ‘Prostate cancer has lagged behind all other common solid tumours in the use of molecularly targeted treatment so it is very exciting that now we can personalise an individual’s treatment based on specific genomic alterations in their cancer cells.’
The only down side of the findings, is that side effects, such as anaemia and nausea, were more common in those taking Lynparza.
A total of 16.4 per cent of patients taking Lynparza discontinued treatment due to adverse events, compared to 8.5 per cent with hormonal treatment.
Dr Efstathiou said: ‘Overall, these data show that, like breast and lung cancers, prostate cancer is not one but many different diseases and we need to start identifying different groups of patients and treating them with targeted therapy.’
Prostate cancer is the most common cancer for men with almost 48,000 diagnoses a year in the UK and more than 1.2million worldwide.
Dr Matthew Hobbs, deputy director of Research at Prostate Cancer UK said: ‘This hugely exciting result represents a revolution in the treatment of prostate cancer.
‘It finally brings prostate cancer medicine into the 21st century by giving us, for the first time ever, a therapy that makes use of genetic testing of the tumour to work out which men will benefit.
‘This kind of precision medicine approach is already used to treat other cancers, and we hope olaparib will become the first of many treatments for prostate cancer which are based on this sort of detailed understanding of an individual man’s tumour.’
The findings were presented at the ESMO 2019 conference in Barcelona.
WHAT IS PROSTATE CANCER?
Prostate cancer is the growth of tumours in the prostate gland.
Only men have a prostate, which is a walnut-sized gland between the rectum and the penis which creates a fluid to be mixed with sperm to create semen.
How many people does it kill?
More than 11,800 men a year – or one every 45 minutes – are now killed by prostate cancer in Britain, compared with about 11,400 women dying of breast cancer.
It means prostate cancer is behind only lung and bowel in terms of how many people it kills in Britain. In the US, the disease kills 26,000 each year.
Despite this, it receives less than half the research funding of breast cancer – while treatments for the disease are trailing at least a decade behind.
How quickly does it develop?
Prostate cancer usually develops slowly, so there may be no signs someone has it for many years, according to the NHS.
If the cancer is at an early stage and not causing symptoms, a policy of ‘watchful waiting’ or ‘active surveillance’ may be adopted.
Some patients can be cured if the disease is treated in the early stages.
But if it diagnosed at a later stage, when it has spread, then it becomes terminal and treatment revolves around relieving symptoms.
Thousands of men are put off seeking a diagnosis because of the known side effects from treatment, including erectile dysfunction.
Tests and treatment
Tests for prostate cancer are haphazard, with accurate tools only just beginning to emerge.
There is no national prostate screening programme as for years the tests have been too inaccurate.
Doctors struggle to distinguish between aggressive and less serious tumours, making it hard to decide on treatment.
Men over 50 are eligible for a ‘PSA’ blood test which gives doctors a rough idea of whether a patient is at risk.
But it is unreliable. Patients who get a positive result are usually given a biopsy which is also not foolproof.
Scientists are unsure as to what causes prostate cancer, but age, obesity and a lack of exercise are known risks.
Anyone with any concerns can speak to Prostate Cancer UK’s specialist nurses on 0800 074 8383 or visit prostatecanceruk.org.