Key messages The research environment has changed since clinical equipoise was first proposed 30 years ago New trial designs—such as umbrella and basket trials, adaptive platform trials, and cluster randomised trials—raise new ethical challenges for evaluating the state of scientific uncertainty and communicating about risks with patients and participants Clinical equipoise needs to evolve We propose the design of specific guidelines to provide ethics committees and trialists with instructions for how to evaluate equipoise in the context of new designs and (...) biomarkers and how to optimise communication with participants. (shrink)