Industry-funded drug trials more likely to report positive results, study finds

The pharmaceutical industry trade group PhRMA said in a statement today that it supports additional transparency.

“PhRMA and its member companies have a longstanding commitment to the ethical conduct of clinical trials and to increasing transparency by reporting more information about clinical trials. ... The study would not have been possible without the large volume of information about ongoing and completed industry-sponsored clinical trials provided through ClinicalTrials.gov and supported by PhRMA and its member companies," it said. “While our review of the study continues, it is important to note that the authors acknowledge that industry-funded trials tended to be for later stages in the lengthy drug development process."

Mandl said it’s possible that pharmaceutical companies are better at picking winners when they decide which drugs to test. But he also noted that industry-funded trials in their study were more likely to compare their drugs to other drugs, while government-sponsored trials tended to compare drugs to placebos. Industry trials also were shorter than government funded ones. Given the inherent conflict of interest when a company tests a drug it is marketing, it would not be surprising, Mandl said, to see doses of the comparative drug or trial durations that put the new drug in the best light.

While Clinicaltrials.gov has evolved to include more data over the years, the authors said it could do more, such as adding information on how trials are conducted, how they are analyzed, and the raw data itself on results. That could make it easier to detect potential bias, Mandl said.

“Our concern is that it is a genuine bias and one that needs to be addressed to make sure the evidence base upon which we practice medicine truly reflects the efficacy of the drugs we are prescribing,” he said.

Dr. Erick Turner of Oregon Health & Science University, who led a 2008 New England Journal of Medicine study on selective publication of antidepressant trials, said in an e-mail interview that he wasn’t surprised by what the Children’s researchers concluded. He also thinks that having study protocols available would help

“The information on registered outcomes listed in ClinicalTrials.gov is often vague,” he said. “To take the protocol suggestion a step further, I have felt strongly that the protocol should be part of the peer review process that leads to manuscript publication.”