Industry-funded studies of breast cancer therapies are more likely to report positive results than non-pharmaceutical funded studies, researchers from the University of North Carolina at Chapel Hill and the Dana Farber Cancer Institute have found. In addition, significant differences exist in the design and nature of clinical trials supported by the pharmaceutical industry compared to trials without industry involvement.
Published online today in Cancer, the journal of the American Cancer Society, the study explores the impact of pharmaceutical-company involvement on breast cancer clinical trial design and outcome. Drug-industry investment in research now exceeds the operating budget of the National Institutes of Health and previous studies have examined the impact on other areas of clinical medicine, but not breast cancer.
"Our study shines a flashlight on the issue of the rising role and potential impact of the pharmaceutical industry on breast cancer research and highlights important questions that need to be addressed through further research," said Dr. Jeffrey Peppercorn, assistant professor of medicine in UNC School of Medicine's division of hematology and oncology and a member of the UNC Lineberger Comprehensive Cancer Center.
"The significance of our study is not to say that the drug industry does anything wrong - they are excellent at developing new therapies, and there are many recent examples in breast cancer research. But if more and more research is funded by drug companies, then the limited amount of funding coming from other sources may need to be directed to address other questions," Peppercorn said.
The researchers reviewed all breast cancer clinical trials published in 10 English-language medical journals in the years 1993, 1998 and 2003. They focused their formal statistical analysis on the 2003 trials because the identification of industry funded or non-industry funded research was likely more accurate due to more stringent disclosure guidelines than earlier periods.
Trials with industry involvement were more likely than non-industry studies to use a single-arm study design, without a comparison group. This isn't surprising, Peppercorn notes, because these studies are a key step in drug development.
In 2003, 57 percent of studies reported pharmaceutical involvement. Of these, 66 percent were single-arm studies. Only 33 percent of non-industry studies used single-arm design.
The industry studies were also more likely to yield positive results; 84 percent of industry-supported studies showed positive results, compared with 54 percent of non-industry studies.
"It's been seen again and again in various branches of clinical medicine that studies that involve pharmaceutical industry sponsorship are more likely to have positive outcomes," Peppercorn said. "It's not fair to say at this point that it's necessarily related to biased interpretation of results." For instance, another explanation could be that industry makes smarter or safer choices about what drugs are brought to trial.
However, as industry funding becomes an increasingly dominant source of research funding, clinical questions that aren't directly related to drug development may be neglected, Peppercorn said. Such questions include the optimal duration for giving a medication or whether certain groups of patients benefit from a medication more than others, he said.