A new blood test can gauge whether prostate cancer patients are likely to respond to medication – or are already resistant to the drug abiraterone.
A research team out of the Institute of Cancer Research (ICR) in London and other organizations analyzed blood samples from 97 patients and found that mutations in the androgen receptor gene predicted resistance to abiraterone. The subjects were over seven times more likely to respond to treatment if they did not harbor these mutations.
Abiraterone is a powerful drug for shrinking tumors and addressing advanced prostate cancer, but it does not work for all men. While highly effective in some patients, 30 to 60 percent do not respond to it, prompting researchers to search for a market to help predict in advance who the drug will benefit.
"We're delighted to have developed a test that appears to predict very accurately whether a patient will respond to abiraterone, and that it can be performed on blood samples – removing the need to take a biopsy,” explained clinical scientist Dr Gerhardt Attard of the Institute of Cancer Research and Royal Marsden NHS Foundation Trust.
A clinical trial comprising up to 600 men is on its way to see how the test can be of benefit.
According to the team, investigating tumor DNA in blood samples offers a good overall picture of the progress of cancer in the body, unlike a biopsy that studies only the sampled area, which comes with risks and is often difficult to do.
ICR chief executive Prof. Paul Workman said that while they are proud to have discovered abiraterone at the ICR and that it has extended thousands of lives in the United Kingdom, they aim to continue researching how it can be effectively used.
"This new study finds that by analysing tumor DNA present in the bloodstream, we should be able to personalize treatment with abiraterone, so that only those who will benefit from the drug will receive it,” he said, calling it another step toward precision cancer medicine.
Prostate Cancer UK research director Dr. Iain Frame added that this research is crucial in veering away from a one-size-fits-all approach to prostate cancer treatment.
“When the clock is ticking for a man with advanced prostate cancer, finding out early that his treatment needs changing can not only save precious time, but can also help avoid unpleasant side effects from a treatment that longer works for him,” Dr. Frame said.
Cancer can lead to resistance to drugs over time. Abiraterone, for instance, hits the male hormone receptor on prostate cancer cells, but was found to stop from working after mutations in the receptor are found.
Cost is another area of concern – the drug was rejected by England’s National Health Service due to its price. The new blood test will then be a way to make it more cost-effective after knowing who will respond to the specific treatment.
The study was published Nov. 4 in the journal Science Translational Medicine.
Photo: Kamyar Adl | Flickr