Two new research studies add to the evidence that giving abiraterone before chemotherapy benefits men – and one identifies some men who benefit even more than most.

by Sophie Lutter

17 Feb 2015

It sometimes seems like abiraterone, often described as a ‘life-prolonging and life-enhancing treatment’ for advanced prostate cancer that no longer responds to hormone therapy, is never out of the spotlight for long. And last week was no exception. The Scottish Medicines Consortium (SMC) announced their decision not to make abiraterone available on the NHS in Scotland for men who haven’t had chemotherapy. And right alongside this, scientists published new research on the effects of abiraterone before chemotherapy.

The results for a long term phase 3 trial of abiraterone before chemotherapy came out at the same time as remarkable results from a second research study, which suggested possible molecular clues to tell us which men abiraterone will work best for.

Research one: Testing abiraterone on men who haven’t had chemotherapy

Respected medical journal, The Lancet, published the final results of a clinical trial that started recruiting patients way back in April 2009. The trial involved over 1,000 men with advanced prostate cancer that no longer responded to hormone therapy, but who had either mild or no symptoms.

By mid way through the trial, the researchers had already noticed that taking abiraterone before having chemotherapy delayed the time it took for men’s prostate cancer to get worse. Those early results showed that it delayed the need for chemotherapy and all its unpleasant side effects.

Last week, they added more good news. Men who were treated with abiraterone and prednisone (a type of corticosteroid treatment that is routinely given alongside abiraterone) before chemotherapy lived longer than men who were given prednisone with a dummy drug (placebo). They survived for 34.7 months on average. This is compared to 30.3 months for men in the placebo group.

That difference of four months (and remember, this is just an average  for some it was longer) may not sound like a long time when you’re healthy. But when we’re talking about your last four months; time to set your house in order, and say goodbye to friends and family – it’s time you wouldn’t want to be without.

So as our Chief Executive, Owen Sharp, said: “These data further confirm the huge benefits of abiraterone for men with incurable prostate cancer who haven’t yet received chemotherapy. We want to see this additional evidence swiftly lead to this use of abiraterone being routinely available for all men who need it in the UK.”

Research two: First clues to who will benefit most from abiraterone

We’ve known for a while now that abiraterone works better in some men than others, but we haven’t had a way to predict exactly who it will work best for. The result of a second research study, based on men on the same clinical trial as above, suggests that might change sooner rather than later.

In this study, the scientists looked at a gene called ERG in 348 men on the main trial. 178 of the men were taking abiraterone and prednisone, and 170 were taking prednisone and the dummy drug. The researchers found three different types of ERG mutation, and the type of mutation a man had made a difference to how he responded to abiraterone.

The first thing to point out is that, on average, it took longer for men’s prostate cancer to visibly start growing again if they were taking abiraterone than if they weren’t – regardless of whether they had an ERG mutation, or what type of mutation it was.

But it took longer for some men than others – and that’s the part that could be really exciting.

Men with one particular type of ERG mutation had on average 22 months before their cancer started growing again, if they were taking abiraterone. This is compared to only 5.4 months for men with the same mutation in the placebo group. The time difference was less marked in men who had a different type of ERG mutation or no mutation at all.

Chief Executive, Owen Sharp added, “It is also encouraging to see a glimpse of how we might be able to pick out those men who men would benefit most from this treatment.  We will continue to support further research to develop ways of targeting treatments, so that in the future we can use the benefits of drugs like abiraterone to maximum effect.”

So where next?

Further research is definitely still on the cards. These results have the potential to lead to a major difference in the way we treat advanced prostate cancer, but it’s very early days. There were relatively small numbers of men in each ERG mutation group in this research. So although this is a really interesting result, and an exciting lead, we do need to see this repeated in a bigger group of men to make sure that the results still hold true.

Scientists also don’t yet know why this particular ERG mutation might mean that men do better on abiraterone. More research that helps us get to grips with this will unlock clues about what causes different prostate cancers to start and stop progressing.

On top of this, the researchers were really honest about having some technical difficulties with this study, which isn’t really surprising for a brand new technique. But it does mean that that they couldn’t see whether there was a mutation or not in around one third of the total patient samples they started with. So there’s a long way to go to make this into a reliable, quick, cheap and easy enough test that all men could have before they start treatment.

This research represents the first clue we’ve found as to why abiraterone might work better for some men than others – and, together with other advances in personalised medicine – it could be a game changer for men with advanced prostate cancer.

Read this next:

Early results from drug trial promising for men with advanced prostate cancer

5 Nov 2014

Yesterday, at a national cancer conference, exciting new results were revealed from a clinical trial of a drug in men with advanced prostate cancer. The trial, funded in part by Prostate Cancer UK and the Movember Foundation, is investigating the use of a drug called olaparib which is used to treat women with ovarian cancer.

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