Early results from drug trial reveal promising findings in men with advanced prostate cancer

Yesterday at the NCRI (National Cancer Research Institute) cancer conference, Professor Johann De Bono revealed exciting new results from a clinical trial he’s leading for 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 in men with advanced prostate cancer.

Olaparib is one of a class of drugs called PARP inhibitors. It is already licensed for use and very effective in treating ovarian cancer. PARP inhibitors work by cancelling out the effect of mutations in the genes responsible for repairing DNA when it gets damaged. In normal cells, damaged DNA is quickly repaired. But when the genes responsible for repairing the broken DNA are mutated, this damage goes unchecked. This can lead to errors in the DNA which can eventually cause cancer. PARP inhibitors work by killing cells with damaged DNA, so preventing tumour growth.

We already know that inheriting mutations in DNA damage repair genes, for example BRCA1 or BRCA2, can increase a man’s risk of developing advanced prostate cancer. But new research has shown that mutations in these genes can still develop over the course of advanced disease in men who didn’t inherit them. (This research also featured in a Prostate Cancer UK sponsored session at the NCRI cancer conference this week led by as discussed by Professor Karen Knudsen.)

That’s why Professor de Bono and his team at the Institute of Cancer Research and the Royal Marsden NHS Foundation Trust are testing olaparib in men without inherited mutations in DNA damage repair genes in a clinical trial called TO-PARP. So far the results have been positive, with some patients with advanced, aggressive prostate cancer having an impressive response to the drug.

And new research published by Dr Gerhardt Attard, a colleague of Professor De Bono at the Institute of Cancer Research, has enabled researchers to take this trial even further. Thanks to Dr Attard’s team, it’s now possible for the researchers to test for mutations in DNA damage repair genes throughout the course of the disease. This means treatments like PARP inhibitors can be targeted to those patients who are most likely to respond, at the earliest possible time.

These are still very early results, so it’s too soon to say for certain that these treatments will definitely be beneficial, but it’s really exciting to see clinical trials investigating new uses for drugs that we already know work well for other cancer types. Finding existing drugs that will work for prostate cancer alongside searching for new ones will speed up the process of getting treatment to the men who need it enormously. And not a moment too soon.