Phase III clinical studies, or confirmatory studies, are the final confirmation of the safety and efficacy of a medicine before it can be launched on the market. Phase III studies are the largest, most complicated, and most expensive part of the medicines development process, and nearly 50% of medicines that enter this phase will fail.
Basics of Medicine Development
Phase II clinical studies, or proof of concept studies, begin to test the effect of a medicine on the target disease in humans. These studies are usually run as double-blinded, randomised studies in multiple sites.
Phase I clinical studies, or proof of mechanism studies, test the safety of a medicine in humans. Usually, these studies are carried out in healthy human volunteers.
During the non-clinical safety testing step of the medicines discovery and development process, molecules undergo safety testing in animal subjects in order to determine whether or not they are acceptably safe to be tested in humans.
During the pre-discovery step of the medicines development process, unmet needs are determined and investment decisions are made.