the-BA : Flawed experiments

By Wendy Barnaby

Basic flaws in animal experiments "results in bias which overstates how effective stroke drugs really are," said Dr Malcolm Macleod, stroke physician at the Western General Hospital in Edinburgh, at the BA Festival of Science.

In a review of 288 animal studies for six treatment for strokes, reported last week in Trends in Neurosciences, Dr Macleod and his colleagues found persistent bias in how effective the intervention was reported as being.

Only one-third of the studies reported allocating animals randomly to different experimental groups.

"Those studies that do randomise say their treatment is about 10 per cent less effective than those who don’t. Being able to decide which animal goes into which group makes a 10 per cent difference in how good the drug looks," said Dr Macleod.

"These studies came from over 100 publications around the world in all sorts of different labs, most not funded by anyone except academic investigators," he said.

Only one-tenth of the groups reported that they had kept secret whether an animal was being given the treatment being trialled.

Only one-third reported that the people who assessed how effective the treatment had been, were ignorant of whether the animals had been given the treatment or not.

Current treatments for stroke have been based "only loosely" on data from animal experiments, he said.

There are three treatments currently used for strokes. "Clot-busting drugs have been tested on animals, and work. Aspirin and stroke unit care haven't been near an animal," he said.

Dr Derek Fry, an animal inspector from the Home Office, distinguished between the standard of clinical trials and animal experiments. Researchers have been "rather slow", he said, at taking these things on for animal experiments.

"Scientists are expecting themselves to be objective, and don’t realise how subjective they can be," he said.

"The studies Dr Macleod was referring to formed, Fry estimated, about one to two per cent of the animal experiments carried out in the UK, and only to studies carried out on rodents.

"Many of these experiments are done within industry establishments where there are a whole lot of economic pressures as well as our pressures," said Dr Fry.

"Where there's a potentially short time to market – where you’re desperately trying to get a drug through the experiments into clinical trials – those pressures to get a good result seem to be much higher," said Dr Macleod.

"So we should be much more careful in the way we do those experiments and in the way we interpret them."

"This isn't to say that animal models of stoke are bad and will never tell us anything. It’s that we can do them better and we must make a substantial effort to improve the quality and the reporting of those studies," he said.

Dr Macleod was representing the CAMARADES Collaboration, which investigates better ways of carrying out and reporting animal experiments.

Read more on this story at the Independent and the Daily Telegraph.