Aiming at a moving target: research ethics in the context of evolving standards of care and prevention.

In rapidly evolving medical fields where the standard of care or prevention changes frequently, guidelines are increasingly likely to conflict with what participants receive in research. Although guidelines typically set the standard of care, there are some cases in which research can justifiably deviate from guidelines. When guidelines conflict with research, an ethical issue only arises if guidelines are rigorous and should be followed. Next, it is important that the cumulative evidence and the conclusions reached by the guidelines do not eliminate the need for further research. Even when guidelines are rigorous and the study still asks an important question, we argue that there may be good reasons for deviations in three cases: (1) when research poses no greater net risk than the standard of care; (2) when there is a continued need for additional evidence, for example, when subpopulations are not covered by the guidelines; and (3) less frequently, when clinical practice guidelines can be justified by the evidence, but practitioners disagree about the guidelines, and the guidelines are not consistently followed as a result. We suggest that procedural protections may be especially useful in deciding when studies in the third category can proceed.