11 Nov 2015

Blood test can measure abiraterone's effectiveness, new trial reveals

Researchers find DNA in blood samples can determine when life-prolonging drug abiraterone has stopped working in men with advanced prostate cancer, giving an early indication when to switch treatments and predicting which men are resistant to the drug altogether.

As every sports fan and team manager understands, knowing when to make a change in the line-up or a last-minute substitution is crucial to the final scoreline.

The same principle holds true for advanced prostate cancer treatments. When the clock is ticking for a man with advanced prostate cancer, getting the timing right on a change in treatments can make all the difference. Knowing – before he feels any symptoms – that a drug is no longer controlling his cancer and so making a timely switch, can not only buy a man some precious extra time, but also prevent him experiencing unpleasant side effects unnecessarily.

Up until recently, there’s been no way to determine when an early substitution might give a tactical advantage. But research we’ve funded with the Movember Foundation in Dr Gerhardt Attard’s laboratory at the Institute of Cancer Research could change all that.

Early indication of when arbiraterone stops working

In a follow-up study from his earlier small-scale observations, Dr Attard and his team have taken blood samples from around 270 men with advanced prostate cancer, who were being treated with the life-extending drug abiraterone.

They found that when men developed either particular point mutations (changes to a single DNA molecule in the sequence that makes up a gene) in the Androgen Receptor gene, or an increase in the number of copies of that gene, it suggested that the drug was no longer working. They could often detect this genetic change months before the man developed symptoms of cancer progression, suggesting that this can give an early indication that it’s time to bring in a substitute treatment.

These are really exciting results, and have huge potential to change the way we treat advanced prostate cancer

Another important finding from this research is that the researchers could detect these mutations in some men before they even started treatment. And these were the men who were less likely to respond well to abiraterone. These results imply that it might be possible to test for these mutations before treatment and not give abiraterone to men who are likely to be resistant to it – another step in the road to making sure that every man receives the medication that is best suited to his particular prostate cancer.

These are really exciting results, and have huge potential to change the way we treat advanced prostate cancer. The next stage for this research will be an even bigger randomised, controlled trial. We know that one size does not fit all when it comes to this disease, and trials like this are giving men the options they need to find the treatment that works best for them.