high indeed. Also, there might be other reasons to continue, such as collecting more long-term safety data. Futility Futility is not as widely recognized as safety and benefit, but actually can be the most common reason to stop a trial. As an example, suppose a trial is one-half completed, but the experimental arm and the control arm have nearly identical results. It's likely in no one's interest to have this trial continue. It is extremely unlikely that the trial, should it continue to its normal end, would have the statistical evidence needed to convince a regulatory agency to approve the treatment. The company sponsoring the study could save money for other projects by abandoning this trial. Also, current and potential trial participants could be freed to take other treatments, rather than this experimental treatment, which is unlikely to benefit them. See also Clinical trial protocol Drug development EudraVigilance Institutional review board Monitoring in clinical trials Pharmacovigilance References Susan Ellenberg, Thomas Fleming, David DeMets, Data Monitoring Committees in Clinical Trials: A Practical Perspective (John Wiley & Sons Inc., 2002) David DeMets, Curt Furberg, Lawrence Friedman, Data Monitoring in Clinical Trials: A Case Studies Approach (Springer, 2006) Jay Herson (2009) Data and Safety Monitoring Committees in Clinical Trials, Chapman & Hall/CRC, External links Clinical research Clinical data management Medical monitoring