A pioneering drug developed to treat women with inherited cancers can also benefit men with advanced prostate cancer, a major new clinical trial concludes. The trial is a milestone in cancer treatment as the first to show the benefits of 'precision medicine' in prostate cancer - with treatment matched to the particular genetic characteristics of a man's tumour.
Olaparib, the world's first drug to reach the market targeted against inherited cancer mutations, was found to benefit as many as a third of patients with prostate cancer, including many who did not inherit cancer genes but whose tumours had acquired defects in DNA repair. The trial's finding were published in the New England Journal of Medicine.
In the trial, 49 men with treatment-resistant, advanced prostate cancer received olaparib, and 16 of them - or 33 per cent - responded, as defined by a set of clinical criteria.
Olaparib stopped prostate cancer growth, generating lasting falls in prostate specific antigen (PSA) levels, falls in circulating tumour cell counts in the blood, and radiological responses on CT scans and MRI.
The clinical trial found that up to 30 per cent of men with advanced prostate cancer had tumours with defects in their systems for repairing DNA detected by genomic testing - and that these responded particularly well to olaparib.
Of the 16 patients with detectable DNA repair mutations, 14 responded very well to olaparib - accounting for the large majority of those who benefited from the drug. Most of these men, who all had terminal prostate cancer with limited treatment options, had disease control lasting much longer than expected in this group of patients.
The results have led on to a second part of the trial in which only men whose prostate cancers have detectable DNA repair mutations will receive olaparib. If the results are successful, olaparib could become a standard treatment option for men with advanced prostate cancer and DNA repair mutations.
Olaparib, which is now owned by AstraZeneca, has had particularly strong results in phase III trials in patients who inherited mutations to the BRCA genes, many of whom had breast or ovarian cancer.
The drug, a type of treatment called a PARP inhibitor, was licensed last year for women with ovarian cancer and inherited BRCA mutations.
Based on material originally posted by Institute of Cancer Research.