Study Finds Industry-funded Drug Trials Yield More Favorable Results

Drug trials funded by industry are more likely to report positive outcomes than are trials funded by other sources. They also are less likely to be published within two years of completion of the study. Those findings come from a study published in the Aug. 3 issue of Annals of Internal Medicine.

The study examined 546 drug trials that were registered in ClinicalTrials.gov, a publicly available Web-based registry of clinical trials established in 1999. The researchers' objective was to determine whether funding sources are linked to published outcomes and other study aspects.

The authors looked at safety and efficacy trials listed in the registry for five families of drugs: anticholesteremics, antidepressants, antipsychotics, proton-pump inhibitors and vasodilators. The trials were conducted between Jan. 1, 2000, and Dec. 31, 2006.

The authors then searched four electronic databases for publications corresponding to the ClinicalTrials.gov trials: NIH's PubMed, John Wily & Sons, Ltd.'s Cochrane Library, Elsevier's Excerpta Medica database and EBSCO Publishing's Cumulative Index to Nursing and Allied Health Literature.

Of the 546 drug trials surveyed, 346, or 63 percent, were funded primarily by industry; 126, or 23 percent, were funded by nonprofit or nonfederal organizations; and 74, or 14 percent, were funded by government sources.

The results of the comparison indicated that industry-funded trials resulted in the highest proportion of articles reporting favorable outcomes, with about 85 percent of those published works reporting positive outcomes for the test drug. Among articles published about nonprofit or nonfederal organization-funded trials, about 72 percent showed favorable outcomes, and 50 percent of publications reporting on government-funded trials were favorable.

"Among the publications, those associated with trials primarily funded by industry were most likely to report a positive outcome. Trials primarily funded by nonprofit or nonfederal organizations that also received industry contributions were more likely than trials without such support to report findings favoring the study drug," said the study's authors.

"These results are consistent with previous studies demonstrating an association between industry funding and the reporting of results favoring experimental drugs marketed by the sponsoring company," they added.

In fact, said the authors, industry-funded trials are more than four times more likely to report findings supporting a product than are trials without an associated financial interest.

For example, in a study of statins manufactured by competing companies, funding from the company marketing the statin being studied was associated with a 16-fold increase in the likelihood of reporting favorable results.

In addition to showing more positive outcomes, industry-funded trials were the least likely to be published within 24 months of study completion. Trials funded by nonprofit or nonfederal organizations that did not receive industry contributions were the most likely to be published within that timeframe.