How 74 years of flawed experiments ‘hampered’ cancer fight

FLAWED animal studies over several decades may have seriously hampered the development of new medicines, research conducted by a team of Scottish scientists suggests.

Jonathan Kimmelman of McGill University. Picture: Jonathan Kimmelman

The scientists have called for new guidance on the design and reporting of pre-clinical cancer studies.

University of Edinburgh analysis of 147 randomly chosen studies published between 1941 and 2012 revealed that a basic step to avoid bias - ensuring researchers were “blind” to what experimental group animals had been assigned to - had only been taken in one in 20 cases.

The investigators also examined more than 1,000 animal studies from the UK’s top five universities published between 2009 and 2010.

Less than a third of these research teams had recorded taking appropriate measures to reduce bias.

Another research group from Canada found that new kidney cancer drug Sutent’s effectiveness had been over-estimated by as much as 45 per cent because of the lax way pre-clinical tests had been conducted.

Lack of rigour may explain why only 5 per cent of agents that show anti-cancer activity prior to patient trials are eventually licensed, said the researchers.

The kidney cancer drug sunitinib launched in 2006, was the focus of a critical in-depth study led by Dr Jonathan Kimmelman, from McGill University. Sold under the brand name Sutent, the drug targets signalling pathways that cause certain cancers to grow. It is also used to treat rare stomach and pancreatic cancers.

Dr Kimmelman said: “Only a fraction of drugs that show promise in animals end up proving safe and effective in humans. An important reason is because studies in animals are often not well designed, and because positive results have a higher chance of being published. They end up skewing what we think we know about the potential of a drug.”

University of Edinburgh professor Malcolm Macleod, added: “It is sobering that of over 1,000 publications from leading UK institutions, over two-thirds did not report even one of four items considered critical to reducing the risk of bias, and only one reported all four measures.”

Guidelines developed in the UK and aimed at improving standards of medical research conducted on animals were published in 2010.