A Phase III clinical study is the pivotal stage of clinical trials in which an investigational therapeutic product is evaluated in a large, randomized, controlled patient population — typically 1,000 to 5,000 or more — to confirm its efficacy, monitor adverse effects, and compare it against existing standard-of-care treatments. Successful Phase III data form the primary basis for regulatory approval submissions to agencies such as the Food and Drug Administration (FDA) and European Medicines Agency (EMA), and require GMP-manufactured clinical supply of consistent quality and potency.
