This year, the National Institute of Health in the United States set up a new programme to explore the development of old drugs for new uses.The concept is not new - one of the first drugs to be repurposed to treat cancer was thalidomide.

In the 1950s, it was used to treat nausea and vomiting in pregnant women. But a lack of robust study data and a hurried drug approval led to congenital deformities in newborns.

Decades later, Harvard clinician-scientists found thalidomide could prevent the growth of blood vessels that feed cancer, said Dr Toh Han Chong, the deputy director of the National Cancer Centre, Singapore (NCCS). In 2006, the US Food and Drug Administration accelerated approval for its use to treat those with newly diagnosed multiple myeloma, a blood cancer.

It became a powerful weapon against this cancer and is now being tested on others, said Dr Toh, a senior consultant at the NCCS division of medical oncology.

Then there are statins, used widely to lower cholesterol levels. Well-known brands include Zocor, Lipitor and Crestor. A large-scale, 15-year study following almost 150,000 post-menopausal women aged 50 to 79 found that those taking statins were more likely to survive cancer.

When all cancers were taken into account, patients on statins were found to be 20 per cent less likely to die of cancer. Still, experts say randomised trials are needed to confirm if the findings were directly due to the drugs' effects.

Ng Wan Ching