All drugs approved by the U.S. Food and Drug Administration (FDA) have been tested in a number of clinical trials. Some trials are specifically designed to test a drug’s safety and efficacy, while others compare different doses or assess potential adverse interactions. Although the FDA reviews data from all of these trials when evaluating a new drug, the pivotal trial directly studies the safety and efficacy of a drug in its intended patient population, including the final dose and formulation that would be included in the label. Often, pivotal trials are randomized and controlled to ensure results are reliable and not biased by external factors.