Definition

A study that confirms how well a new treatment works after it was shown in early-phase clinical trials that it might be beneficial for patients. New drugs that are given an accelerated approval by the U.S. Food and Drug Administration (FDA) to treat a serious or life-threatening disease, such as cancer, are required to be tested in a confirmatory clinical trial. This is done to verify that they really work when they are tested on many more people in a randomized study. The FDA may remove a drug from the market if a confirmatory clinical trial shows that the drug is not beneficial for patients.