A clinical trial is a carefully designed study which tests the benefits and risks of a specific medical treatment or intervention, such as a new drug or a behavior change (e.g., diet). Once researchers have completed a rigorous screening and preclinical testing process, the company files an Investigational New Drug (IND) application with the U.S. Food and Drug Administration (FDA). This application allows the investigational medicine to be tested in human volunteers in clinical trials.
Every clinical trial is led by a principal investigator, who is usually a doctor, along with a team of nurses and others researchers. The FDA requires a multi-phase clinical trials process to be completed before deciding if the medicine under investigation is safe and effective for a broader patient population. Usually, the number of human volunteers in the trial increases as the treatment moves through these phases, which is why innovative medicines cannot be developed without the help of volunteers who participate in clinical trials.