Drug studies "biased" towards sponsors

The American Journal of Psychiatry has published an analysis of head-to-head clinical trials, in its April issue, that appears to suggest that many trials show bias towards the sponsoring company's product. The report, titled: Why Olanzapine Beats Risperidone, Risperidone Beats Quet-iapine and Quetiapine Beats Olanzapine: An Exploratory Analysis of Head-to-Head Comparison Studies of Second-Generation Antipsychotics, was compiled by identifiying comparison studies of second-generation antipsychotic drugs for the period 1999 to February 2004. The abstracts of the studies that were partially or fully-funded by phar-maceutical companies were modified to mask the names and doses of the drugs employed in the trial. Two physi-cians blinded to the study sponsor were asked to evaluate the abstracts and rate which drug was favored by the over-all outcome measures. Two other doctors reviewed the full studies (including the details of the sponsor and the pro-ducts) for sources of bias that could have favorably affected the sponsor's drug.

The results of the research indicate that, out of 42 reports, 33 were sponsored by an individual drug firm. The study found that, in "90.0%" of these cases, the overall outcome was favorable to the sponsored drug. However, if 30 reports out of 33 were biased in favor of the sponsors, the correct figure should have been 90.9%.

"Minor modifications" would help avoid bias