At what level of collective equipoise does a randomized clinical trial become ethical for the members of institutional review board/ethical committees?

Background: The conduct of a randomized controlled trial (RCT) is deemed ethical only if we are in state of "equipoise" as to which treatment would be most beneficial for the patients. Individual equipoise applies to an individual clinician or a member of ethical, institutional review board (IRB), whilst collective equipoise refers to the profession as a whole. It is argued that physicians are not bound by the equipoise but their actions are directed by the confines of the expert opinion.