Olaparib has already shown positive signs in treating women with gene defects linked to the condition, accounting for about five to 10 per cent of breast and ovarian cancer cases. Now it has, for the first time, been shown to reduce the size of tumours in a much wider group of ovarian cancer patients.
The findings, published in Online First in The Lancet Oncology, highlight the potential of olaparib to treat patients with more common non-hereditary tumours and could offer a new treatment option.
Lead author Karen Gelmon, from the BC Cancer Agency in Vancouver, Canada said: “Olaparib represents a promising therapeutic option for patients with this aggressive malignant disease for whom treatment options are limited to toxic chemotherapies.”
In the latest stage of trials designed to evaluate the drug’s effectiveness in the treatment of breast and ovarian cancers for those with non-hereditary tumours.
Between July 2008 and September 2009, 92 patients, 65 with ovarian cancer and 26 breast cancer, were given 400mg of olaparib twice daily for four weeks.
Among women with ovarian cancer, 41 per cent with hereditary tumours showed a substantial shrinkage in the size of their tumours compared with 24 per cent of patients with non-hereditary tumours.
None of the patients with breast cancer had an objective response.
The authors conclude: “New treatments targeting DNA repair mechanisms seem to provide new hope for treatment of ovarian cancer.”
Melinda Telli from Stanford University School of Medicine, California, welcomed the potential of this new class of genetically-targeted drugs.
She said the findings not only suggests new therapeutic possibilities for women with this type of ovarian cancer, but also importantly confirms the hypothesis that patients with common non-hereditary tumours can be targeted effectively with the therapy.
Earlier this month it was also revealed that a single faulty gene has been found to raise the risk of ovarian cancer six-fold, giving a woman more than a one in 11 chance of developing the disease.
The discovery was hailed as a landmark by Cancer Research UK. It paves the way to an early diagnostic test which could be available within two to three years.
Each year around 6,500 new cases of ovarian cancer are reported in the UK and more than 4,000 women die from the disease.
The cancer, which has been dubbed “the silent killer” has few early symptoms and is often diagnosed at a late and dangerous stage.
Women in the general population have a one in 70 chance of developing the disease. But for women with the newly identified gene defect, the odds rise to one in 11, increasing their risk six times.