All drugs approved by the FDA have been tested in a number of clinical trials. Some trials are specifically designed to test a drug’s safety and effectiveness, 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, certain trials are considered more significant than others and given additional scrutiny. The most attention is typically given to trials that directly study the safety and effectiveness of a drug in its intended patient population. A trial is often deemed “pivotal” if it has undergone this close scrutiny and been determined to provide strong evidence of a drug’s safety and effectiveness. Thus, pivotal trials are said to serve as the basis of FDA approval.