BRITAIN: British scientists say they have identified a potential new treatment for patients with certain types of hereditary breast cancer.
Women with mutations in the BRCA1 and BRCA2 genes have an 85 per cent risk of developing the disease by the time they reach the age of 70.
But researchers funded by the charities Cancer Research UK and Breakthrough Breast Cancer said a new drug known as a PARP inhibitor takes a new approach to killing cancerous cells.
"It could be a much more effective and less toxic replacement for chemotherapy," said Prof Alan Ashworth of the Institute of Cancer Research in London.
"This is a brand new therapeutic approach, centred on exploiting a specific deficiency in breast cancer cells - in their Achilles' heel."
Unlike standard chemotherapy drugs that kill both healthy and cancerous cells, the new treatment being developed by the British company KuDOS Pharmaceuticals, a spin-off firm of Cancer Research UK, only targets cancer cells.
Mutations in the BRCA1 and BRCA2 genes damage a DNA repair mechanism and allow tumours to grow. The new therapy is aimed at cells where the DNA repair mechanism is missing.
Dr Andre Tutt of Guy's Hospital in London, who worked on the research, described it as a completely new approach in the fight against this type of cancer.
In two research papers published in the science journal Nature, Prof Ashworth and his team and Thomas Helleday of the University of Sheffield in England showed that blocking the PARP enzyme slows the growth of BRCA2-deficient tumours in mice with no serious side-effects.
They believe the same approach could be used to treat the 1-2 per cent of human breast cancers that are caused by the BRCA mutations and the underlying biochemical defects that may be present in up to 20 per cent of breast cancers.
"Within a couple of months we are going to start phase 1 trials, where you look for toxicity," said Prof Ashworth, adding that if all goes well a pill could be available in about five years.
Breast cancer is the most common malignancy affecting women.
More than one million cases occur worldwide each year, according to the International Agency for Research on Cancer in France.