Anti-cancer drugs known as angiogenesis inhibitors, which prevent the formation of blood vessels that feed tumours, can make the disease worse, according to the Breakthrough Breast Cancer Research Centre.
It cites Sutent, used to treat kidney cancer, and Avastin, used to treat bowel, breast and lung cancers, which are on the market after successful clinical trials.
The research, at the Institute of Cancer Research in London, focused on cilengitide, an experimental inhibitor that has not yet been licensed for patients.
Writes Dr Andy Reynolds in the journal Nature Medicine: “Our study revealed a previously unknown mechanism through which drugs such as cilengitide behave.
“It showed that while higher concentrations of cilengitide can block angiogenesis, lower concentrations can actually stimulate the supply of blood to the tumour and can promote its growth.”
On a positive note, he says that “knowledge of this mechanism will help us develop new ways to make these drugs as effective as possible. We may be able to combine them with other drugs to maximise their effectiveness.”
Dr Lesley Walker, director of cancer information at Cancer Research UK, said: “Sometimes very subtle alterations to the way a drug is administered, or subtle changes to a drug’s structure, can have a huge impact.”
Copyright Press Association 2009