A drug which is currently used to treat different types of addiction, may have a beneficial effect on some cancer patients, new research suggests.

Naltrexone is currently licensed in many countries for the treatment of alcohol and heroin addiction. However UK scientists have found that it also appears to stop cancer cells from growing and alters how these cells work, making them more likely to kill themselves.

The doses required for this are far lower than the doses that would usually be used to treat addiction.

"We have shown that the genetic fingerprint of naltrexone differs according to the different doses used, which identifies new ways of using it as an anti-cancer treatment.

"Rather than stopping the cancer cells from growing, patients want to be rid of them. We saw that by giving the drug for two days, then withdrawing it, cancer cells would stop cycling and undergo cell death," explained lead researcher, Dr Wai Liu, of St George's University.

He believes that naltrexone could be used in conjunction with other cancer treatments and he is hoping that these findings will prompt clinical trials of this drug among cancer patients

"We have taken a drug that is relatively safe in humans, and reformulated a new use for it. This has only been possible by understanding the dynamics of a drug. How many other drugs can be improved in this way?

"We have shown a similar 'repackaging' benefit with the antimalarial drug artesunate and the cannabinoids. In both cases, drugs that are not classically cancer therapies are being trialled as such," he commented.

These findings have been published in the International Journal of Oncology.