Most clinical trials run as planned from beginning to end. But teams are constantly monitoring trials to be sure that the study should continue. Two of the groups that monitor trials are the Institutional Review Board and the Data Safety and Monitoring Board. Sometimes, they will stop a trial early.
A trial might be stopped because:
- For example, they may stop a trial if the people taking part are having unexpected and severe side effects.
- Or they may stop a trial if there is clear evidence that the harms are greater than the benefits.
- It is going very well. If there is clear evidence early-on that a new treatment or intervention is effective, then the trial may be stopped so that the new treatment can be made available to others as soon as possible.
- Enough people cannot be recruited to take part.
- The results of other trials are published that answer the research question or make it irrelevant.
Text adapted from the National Cancer Institute; images provided by Genentech. Reviewed on November 15, 2023.