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CLINICAL TRIALS
CliniCal OnCOlOgy news • april 2012
Evidence-based Medicine
‘The differences in the results clearly point to differences
STUDIES
in research agendas between publicly versus industry-
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therapeutic success in favor of sponsor’s treatment. Speaking at the 2011 annual meeting of the American Society of Hematology, Benjamin Djulbegovic, MD, PhD, reported that the equipoise hypothesis appears to drive the results observed in publicly sponsored trials, whereas the design-bias hypothesis can explain the outcomes obtained in the industrysponsored trials. This conclusion was based on a retrospective analysis of the results of all Phase III studies sponsored by GlaxoSmithKline (GSK) or the National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) from 1980 through June 2010. Using three metrics to assess treatment success in clinical trials, Dr. Djulbegovic, of the Center for Evidence-Based Medicine and Health Outcomes Research, University of South Florida and H. Lee Moffitt Cancer Center & Research Institute in Tampa, and colleagues found that new treatments are favored over standard treatments in industry-sponsored trials in comparison with trials funded by the public funder for each metric used. Of the 40 trials funded by industry (19,889 patients) and the 77 trials funded by NCIC CTG (33,260 patients), 42% of the industry-sponsored studies and 25% (P=0.04) of the public sector–sponsored studies showed a statistically significant superiority of experimental treatment over the control arm for the primary end point. Investigators themselves concluded that new treatments were superior to standard treatments in 80% of GSK versus 44% of NCIC CTG trials (relative risk, 1.81; P<0.001). Pooled quantitative analysis for the primary outcome indicated higher success rate in GSK trials (odds ratio [OR], 0.61; 99% confidence interval [CI], 0.47-0.78] versus OR, 0.86; CI, 0.741.00; P=0.003). However, testing for the effect of treatment over time indicated that treatment success has become similar in the last decade. In addition to equipoise versus design bias as the main explanation of the results, a number of other explanations are possible. They include a possibility that the results can be explained by the larger proportion of industry-sponsored trials relying on the use of placebo as a comparator, as well as differences in mix between the proportion of explanatory and pragmatic trials in industry versus publicly sponsored trials. Pragmatic trials are rarely done by industry and the effect sizes are expected to be larger in explanatory trials, which can explain the differences in the results. Overall, Dr. Djulbegovic concluded, “the differences in the results clearly point to differences in research agendas
sponsored trials.’
industry-sponbetween publicly versus industry-spon sored trials.” Asked to comment on these results, Smita Bhatia, MD, director of outcomes research at City of Hope in Duarte, Calif., called this a “a well-conducted study” that generated “intriguing
—Benjamin Djulbegovic, MD, PhD
findings,” but she considers the conclusions to be preliminary and awaits a study with a larger scope. “While the findings provide food for thought, they need to be confirmed in future studies that include representation by more than one pharmaceutical company, unlike the current study that relied on
data from only one,” Dr. Bhatia said. The findings may be useful when considering differences between industry- and publicfunded studies. —Ted Bosworth Dr. Djulbegovic reported receiving research funding from Millennium; Dr. Bhatia reported no relevant disclosures.
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