Breast cancer drug shows promise in treating prostate cancer
Results from a new clinical trial show Olaparib, a gene-targeted drug currently licensed to delay progression of breast and ovarian cancer, can also delay progression of prostate cancer in patients with key genetic mutations.
Olaparib is a PARP inhibitor that targets cancer cells that are unable to effectively repair their DNA. Approximately 27% of men with prostate cancer have this mutation in their genes, notably in the BRCA1 and 2 genes. Overall, in 47% of prostate cancer patients with this genetic mutation in their tumour, results showed that olaparib delayed cancer progression for a median of 5.5 months. In patients specifically with the BRCA mutation, cancer progression was delayed for a median of 8.3 months, while 35% of patients were progression-free for over a year. This was despite men in the trial having advanced, heavily pre-treated, prostate cancer.
A phase III trial of the drug is now underway, and it is thought that the targeted treatment could benefit 4000 men in the UK per year by delaying time before the cancer becomes deadly. The phase II study, called TOPARP-B, was led by researchers at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust. Results were presented at the American Association of Clinical Oncology Annual Meeting.
Professor Johann de Bono, Regius Professor of Cancer Research at The Institute of Cancer Research, London, and Consultant Medical Oncologist at The Royal Marsden, said:
‘Our study is exciting because it shows just how powerful genetic targeting and precision medicine can be. We have shown that by testing for DNA repair mutations we can select those patients with a high chance of responding well and for a long time to the targeted drug olaparib.
‘We were delighted to see such strong responses in men with very advanced cancers, where BRCA mutations and other faults in DNA repair genes were present within their tumours. The next phase of the trials is now under way and, if the results look as good as we hope, we should see olaparib starting to reach the clinic for men with prostate cancer in the next couple of years.’