Adding abiraterone to hormone therapy at the start of treatment for prostate cancer improves survival by 37%, according to the results of one of the largest-ever clinical trials for prostate cancer.
The results were presented at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, US, and published in the New England Journal of Medicine on Saturday 3 June 2017.
The results from the Cancer Research UK-funded STAMPEDE trial could change the standard of care for men with prostate cancer, making abiraterone a first-line treatment alongside hormone therapy.
This part of the STAMPEDE trial recruited around 1,900 patients. Half the men were treated with hormone therapy while the other half received hormone therapy and abiraterone. In men who were given abiraterone there was a 70% reduction in disease progression.
The drug is usually given to men with advanced prostate cancer that has spread and has stopped responding to standard to hormone therapy, but this study shows the added benefit to patients who are about to start long-term hormone therapy.
Professor Nicholas James, Chief Investigator of the Cancer Research UK-funded STAMPEDE trial from the University of Birmingham, said: “These are the most powerful results I’ve seen from a prostate cancer trial – it’s a once in a career feeling. This is one of the biggest reductions in death I’ve seen in any clinical trial for adult cancers.
“Abiraterone is already used to treat some men whose disease has spread but our results show many more could benefit. In addition to the improvements in survival and time without relapse, the drug reduced the rates of severe bone complications, a major problem in prostate cancer, by more than a half. I really hope these results can change clinical practice.”
Alfred Samuels, 59, was diagnosed with advanced prostate cancer in January 2012 and joined the STAMPEDE trial two months later. He lives in Harrow with his partner and five children.
Alfred said: “It felt like my world fell apart overnight. The doctors explained that surgery wasn’t an option for me because the cancer had spread beyond my prostate.
“But my clinician suggested that the STAMPEDE trial might be a good option. As part of the trial, I started taking abiraterone four times a day and had a hormone injection every eight weeks.
“During the first six months, tests showed that the treatment was working. I’m still on the trial, which I find reassuring and, fortunately, my cancer is being managed well.”
Learn more about the story of how abiraterone was developed, with work first starting in the 1990s.
Prostate cancer cells usually depend on testosterone to grow. Standard hormone therapy blocks the action of male sex hormones, halting the disease. Abiraterone goes further and shuts down the production of the hormones that fuel prostate cancer’s growth.
Each year around 46,500 men are diagnosed with prostate cancer in the UK, and around 11,000 men die from the disease.
The STAMPEDE trial is coordinated by the Medical Research Council (MRC) Clinical Trials Unit at UCL and funded by Cancer Research UK. Previous results from the trial have already changed clinical practice – data released last year has led to docetaxel chemotherapy now being part of the standard of care for many men with prostate cancer. More data will come out in subsequent years, because of the innovative design of the trial.
Professor James added: “We are so incredibly thankful to the patients and clinical staff who have agreed to take part in this study. With their generosity, scientists can carry out research that will help save lives.”
'Clear benefits for patients'
Professor Johann de Bono, Regius Professor of Cancer Research at The Institute of Cancer Research, London, and Consultant Medical Oncologist at The Royal Marsden NHS Foundation Trust, was an author on the new study. He said: “In the STAMPEDE trial, we aimed to find out if adding abiraterone to standard hormone therapy from the outset of treatment extended the lives of patients with advanced prostate cancer.
“These results show that abiraterone used at the start of treatment had clear benefits for patients, with those who received the drug alongside hormone therapy over a third more likely to survive than those who did not.
“Abiraterone is already now being used before chemotherapy, at an earlier stage than initially had been the case, and it’s really exciting to see that it could start benefiting patients as soon as they are diagnosed. I hope that the data from this trial will soon result in a change of practice in the clinic.”
Professor Paul Workman, Chief Executive of the ICR, said: “Abiraterone has already hugely improved the outlook for hundreds of thousands of men with advanced prostate cancer worldwide. Now, the new results tell us that patients just starting hormone therapy can also benefit from this drug, which was discovered here at the ICR.
“Abiraterone is a highly innovative treatment that not only improves survival rates but has lower rates of side-effects than conventional therapies. I’m keen to see abiraterone assessed by NICE for use in patients as early as possible in their treatment, to maximise the benefit that people get from taking it.”