Many commentators have expressed concern that large investments in biomedical research over the past two decades have not been translated effectively into clinical applications. In its Critical Path Report, the Food and Drug Administration characterized the problem as a “technological disconnect between discovery and the product development process,” and documented that the number of investigational new drugs submitted to the agency had declined “significantly” since 2000. Along a similar vein, another study found that only five of 101 basic science studies (...) showing significant therapeutic promise were successfully translated into clinical applications.This perceived translational lag is stimulating a shift toward human testing of study interventions earlier in the drug development process. One indication of this trend is a recent guidance encouraging sponsors to pursue human “exploratory” studies before embarking on phase I trials. (shrink)