The Christie Charity
Press release posted 3 December 2024
The STAMPEDE trial has recruited nearly 12,000 participants, making it the world's largest intervention prostate cancer trial.
It's a landmark study that has produced multiple practice-changing results, improved life expectancy for patients with advanced prostate cancer and informed how many complex clinical trials are structured.
The latest results, presented at this year's European Society for Medical Oncology conference, show that metformin – a drug that’s commonly used to treat type 2 diabetes – can reduce the side effects of hormone therapy in men being treated for advanced prostate cancer.
Hormone therapy is very effective in stopping cancer progressing, but it also affects the body’s metabolism, leading to side effects, such as weight gain and insulin resistance. This may lead to diabetes and an increased risk of heart disease, stroke, and other health problems in the future.
Metformin affects the way the body processes energy from sugars and fats. As cancer cells process energy differently to normal cells, researchers were interested in whether metformin could help prevent prostate cancer growth and progression. Researchers also aimed to see if metformin could prevent some of the side-effects of hormone therapy.
After 2 years, men assigned metformin added to standard treatment had gained only half as much weight (2kg) as those assigned standard treatment only. They also had lower levels of blood sugar and harmful circulating fats, including cholesterol. Fewer patients in the metformin group also reported signs of metabolic syndrome – a group of health problems which increase the risk of developing type 2 diabetes and heart disease.
Fewer patients in the metformin group also reported signs of metabolic syndrome – a group of health problems which increase the risk of developing type 2 diabetes and heart disease.
On average, people taking metformin had a 10% lower risk of dying and lived for around 6 months longer than those who had standard treatment only*. There was evidence that this effect was greater in men with more advanced forms of the disease. However, this is a preliminary finding, and researchers say further research is required to confirm and understand it.
Between 2016 and 2023, 1,874 people with metastatic prostate cancer joined the metformin comparison of the STAMPEDE trial. Only people who did not have diabetes could take part in this comparison.
Professor Noel Clarke, consultant urologist at The Christie NHS Foundation Trust, a specialist cancer centre in Manchester, is one of the principal investigators of the trial and played a key role with the STAMPEDE team in designing the study.
“STAMPEDE really is a landmark trial. It’s changed practice, saved the lives of countless men, and influenced how complex clinical trials are run. The whole STAMPEDE team is proud to have been so closely involved in it over many years,” comments Professor Clarke. “Hormone therapies, although very effective for prostate cancer, come with unwanted side effects which negatively impact patients’ health and quality of life. As doctors, we want to be able to help our patients live the best lives they possibly can so it’s great to see that a cheap and effective drug that is currently used for diabetes can be used in this way. I hope that this new indication for use will be available on the NHS quickly so that more patients can benefit.”
*The current standard-of-care for prostate cancer that has spread includes hormone therapy. Most patients also receive chemotherapy using the drug docetaxel as part of their standard treatment, and some patients receive radiotherapy.