Pro/con clinical debate: It is acceptable to stop large multicentre randomized controlled trials at interim analysis for futility. Pro: Futility stopping can speed up the development of effective treatments.

A few recent, large, well-publicized trials in critical care medicine have been stopped for futility. In the critical care setting, stopping for futility means that independent review committees have elected to stop the trial early--based on predetermined rules--since the likelihood of finding a treatment effect is low. For bedside clinicians the idea of futility in a clinical trial can be confusing. In the present article, two experts in the conduct of clinical trials debate the role of futility-stopping rules.