Clinical trials to demonstrate the safety and efficacy of new drugs are expensive investments for pharmaceutical companies and other funding organizations—and failures can mean scrapping years of pricey work and going back to the drawing board. Perhaps it is little wonder then that this industry has backed a higher percentage of clinical trials with positive outcomes than either foundations or the government, according to a new study of more than 500 recent drug trials. The results of the analysis were published online August 2 in Archives of Internal Medicine.

The researchers assessed results and publication of 546 studies described on the open reporting site that were testing antidepressants, cholesterol medication, antipsychotics, proton-pump inhibitors or blood pressure drugs, between 2000 and 2006. About two thirds of the trials had published their results by the end of the study period.


The majority (63 percent) of trials in the analysis period were primarily funded by the industry and of those that were, 85 percent of them reported positive outcomes—compared with 72 percent of the nonprofit or other nonfederal institution or 50 percent of those funded by the government.

"Publication bias is likely a contributing factor," Florence Bourgeois, of the Children's Division of Emergency Medicine at Children's Hospital Boston and lead author of the study, said in a prepared statement. "But there are likely many more, including biases in study design, patient selection, data analysis and results reporting." The researchers found that the industry-sponsored trials tended to be in later stages, such as phase 3 or phase 4, than trials backed by other sources, which might explain the increased likelihood of positive results ("because there is more certainty about the drug's efficacy and safety at this advanced stage in the drug-development cycle," the study authors noted).

The Web site went online in 1999 "in response to increasing concerns over the lack of transparency in the conduct of clinical trials," the researchers noted in their paper. But the process has not become transparent enough for everyone.

"While we cannot specifically point to which factors contribute to the association between funding source and positive result reporting, our findings speak to the need for more disclosure of all elements of a study," Bourgeois said.

Image courtesy of Wikimedia Commons/Linda Bartlett