NEW YORK (Reuters Health) - Funding from drug companies and other potential conflicts of interest did not influence the conclusions reached by researchers testing new cancer treatments over the past few years, according to a new analysis.
But Dr. Aaron Kesselheim, who has looked into that issue at the Harvard School of Public Health, pointed out that other studies have shown the opposite.
"One study put against the mass of data suggesting the funding of the study does relate to the outcomes I don't think changes anything necessarily," Kesselheim, who wasn't involved in the new research, told Reuters Health.
The new report, which assessed publications in major cancer journals between 2008 and 2011, found the authors of more than two-thirds of the 150 trials had at least one conflict of interest.
However, only a given trial's results - and not who funded it - influenced their conclusions, the study team wrote Monday in the Journal of Clinical Oncology.
One past study suggested transparency rules at medical journals were all over the map - and some didn't have clear policies about reporting conflicts of interest at all (see Reuters Health story of June 22, 2011 here: reut.rs/n7NxRy ).
Many journals have firmed up their policies in recent years, which the new findings suggest may be having a positive effect, Kesselheim said.
"I would agree with the authors that based on their study, the financial disclosure information that authors are now required to provide for most credible medical journals does impact their writing (and) how they present data," said Dr. David Johnson, head of internal medicine at the University of Texas Southwestern School of Medicine in Dallas.
"All transparency can be beneficial," he added.
Industry affiliations may still affect what authors highlight or downplay about their findings, he pointed out, as well as whether certain trial data are published at all.
Dr. Rachel Riechelmann from the Instituto do Cancer do Estado in Sao Paulo, Brazil and her colleagues analyzed 150 trials and linked editorials on experimental treatments for a range of cancers.
Overall, just over half of those trials were funded by industry and 69 percent had a conflict of interest listed for at least one researcher.
Close to 55 percent of the trials found the experimental therapy worked. In their discussion of the findings, authors were "positive" or "highly positive" about the treatment in question for 51 to 53 percent of trials, regardless of whether they had reported a conflict of interest, Riechelmann and hear team wrote.
Unlike in some previous analyses, they said, the new data suggest conflicts of both researchers and editorial writers "did not influence their interpretation of trial results."
Johnson, who wrote a commentary published with the report, said doctors should still be cautious about new research and closely evaluate how studies were conducted - whether or not they were funded by a drug company.
"I think we should always maintain a level of healthy skepticism when new reports emerge about a new therapy," he told Reuters Health.
Johnson said doctors and researchers should wait for second and third studies backing up the first before moving forward with a new treatment - and then "remain vigilant" for any worrisome findings that may come later.
SOURCE: bit.ly/ZU7Yeu Journal of Clinical Oncology, online April 29, 2013.