MONDAY, Feb. 26, 2007 (HealthDay News) -- Breast cancer treatment trials that are funded by drug companies are more likely to show positive results than studies sponsored by other sources, new research suggests.
There are also major differences in trial design when the pharmaceutical industry foots the bill, the researchers added.
"This doesn't have implications tomorrow for patients, but it does have implications for the kind of questions we address and the kind of answers that we have for future patients," said study author Dr. Jeffrey Peppercorn, an assistant professor of medicine at University of North Carolina School of Medicine.
The findings appear in the April 1 issue of Cancer.
The drug industry now spends more money on research and development than the U.S. National Institutes of Health. And collaborations between industry and academic medical centers have accelerated, raising questions about the quality of research and potential conflicts of interest.
Previous research has shown that clinical trials of drugs funded by pharmaceutical companies and other for-profit entities were more likely to report positive findings than similar trials funded by nonprofit groups.
Only one of those studies looked at cancer trials, however. Meanwhile, half of all pharmaceutical company-sponsored drugs currently in the pipeline are for cancer.
Breast cancer is the most common cancer affecting American women, striking more than 200,000 women in the United States, and more than 1 million worldwide, each year.
Until now, no one had undertaken a systematic study of pharmaceutical sponsorship of clinical research in breast cancer.
For this study, Peppercorn and his colleagues reviewed 140 studies in 10 English-language journals that reported breast cancer treatment results over the past decade.
Of the 140 studies, almost half (48 percent) reported some form of drug company involvement. Drug company participation increased over the period in question, from 44 percent in 1993 to 58 percent in 2003.
Eighty-four percent of studies published in 2003 that reported drug company involvement were positive, vs. 54 percent of studies with other funding sources.
Trials with ties to industry were also more likely to have a single-arm study design, meaning the drug's effectiveness was not tested against a comparison group. Of the 2003 studies, 66 percent were single-arm studies while only 33 percent of studies funded in other ways used this design.
Industry-sponsored trials were also more likely to involve patients with advanced disease.
"We found significant differences in the types of studies by pharmaceutical and non-pharmaceutical funders," Peppercorn said. "Companies may be very good at drug development but, as they play a larger and larger role in financing clinical research, we need to think carefully about what other clinical questions need to be addressed that drug companies may not be exploring."
One expert tried to put the finding into perspective.
"This doesn't surprise me because most of the new drugs being discovered are being discovered by the pharmaceutical industry," said Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, La. In contrast, "in the 1980s, most of the new compounds were discovered by the National Institutes of Health and they went to the pharmaceutical industry with interesting compounds and had them develop products," Brooks said.
Also, 20 years ago, many people didn't feel cancer was a disease they could actually affect so there weren't as many drugs in the pipeline, Brooks said.
"The pharmaceutical industry knows more about the drugs it's bringing to trial so when they design a trial, they have a higher chance of a positive trial," Brooks said. "In terms of a single-arm trial, if the trial demonstrates a dramatic improvement in survival, do you really need to do a large study? We're looking at a very concrete endpoint: death."
For now, breast cancer patients need to keep the dialogue open with their physicians.
"Systemic issues in cancer trials or other medical trials will never be more important than patients discussing with own physician options available, including clinical trials," Peppercorn. "For the individual patient, the specifics of a particular clinical trial are more important than the funding."
For more on clinical trials, visit the U.S. National Institutes of Health.