ADHD

Research funded by drug companies is more likely to produce results that favour the sponsor's product, reveals a new study.

Researchers analyzed 30 previous reports examining pharmaceutical industry-backed research and found the conclusions of such research were four times more likely to be positive than research backed by other sponsors.

New Scientist

May 03 ADHD

Shaoni Bhattacharya

"What we found was that in almost all cases there was a bias - a rather heavy bias - in favour [of a drug] when the study was industry funded," study leader Joel Lexchin told New Scientist.

The main reasons for this, say the team, may be that positive studies are more likely to be published than negative ones. Also, inappropriate comparison drugs may be used in these trials, skewing findings in favour of the tested product.

The new analysis is published in a special issue of the British Medical Journal, which focuses on the close relationship between doctors and the pharmaceutical industry.

Two to entangle

"Doctors, drug companies and most importantly patients would all benefit from greater distance," cautions BMJ editor Richard Smith. "It does of course take two to entangle, and we hope that nobody will see this theme issue as anti-drug company."

But Richard Ley, a spokesman for the Association of the British Pharmaceutical Industry, rejects the study's findings. "The average drug takes 10 to 12 years to develop and costs £350 million - even if you are the most selfish company in the world you can't afford to risk the time and money [to produce biased results]," he told New Scientist.

The clinical trials are overseen from start to finish by independent ethics committees, says Ley, with final checks made by a country's licensing authorities.

Quality scale

Lexchin, an expert in pharmaceutical policy at York University in Toronto, Canada, and colleagues analysed 30 studies examining drug-industry backed trials between 1966 to 2002.

Industry sponsored studies were less likely to be published than research funded by other sources. However, drug company backed studies were four times more likely to show favourable results than studies funded by other sponsors.

But of the 13 studies that looked at the scientific methods used, none reported that the industry-backed trials were of lower quality. Lexchin says this is because standard scales used to examine scientific quality do not cover all issues, such as what drug was used in a trial as a comparison.

Industry-backed studies often compare a new drug to placebo or a second line agent, he says, which makes it easier to get a positive result for a new drug. "My preference would be to compare with what's recommended as the current best therapy," he says.

Lexchin notes that in Canada and the US, the pharmaceutical industry is the largest funder of medical research. "It does have implications in terms of whether or not we can believe the results of research they are funding" he says. "I certainly hope we can, but our study raises questions."