Yet important gaps remain. In the March 2010 issue of PLoS Biology, Emily S. Sena and coauthors provide the most detailed analysis yet of one of these gaps: nonpublication of preclinical (animal) studies. They aggregated results of 16 systematic reviews of preclinical studies involving acute ischaemic stroke, and used statistical methods to estimate the degree of publication bias, and the likely effect of publication bias on measured disease responses. Among other things, they found that 16% of animal experiments were not published, leading to a 31% overstatement of efficacy. The authors note: "we estimate that for the interventions described here, experiments involving some 3,600 animals have remained unpublished. We consider this practice to be unethical."
The authors urge that central registries of preclinical studies be established and maintained-- a call that is not likely to go heeded anytime soon by companies that have much at stake in the secrecy in preclinical research. But their proposal ought to be taken seriously by anyone committed not only to respecting animals used in medical research, but also protecting the welfare of human beings who might enroll in possibly unwarranted clinical research. (photo credit: amy allcock 2009)