phase III

Definition of phase III clinical trial

phase III clinical trial

(fayz … KLIH-nih-kul TRY-ul)
A study that tests the safety and how well a new treatment works compared with a standard treatment. For example, phase III clinical trials may compare which group of patients has better survival rates or fewer side effects. In most cases, treatments move into phase III clinical trials only after they meet the goals of phase I and phase II clinical trials. Phase III clinical trials may include hundreds of people. Also called phase 3 clinical trial.

Source: NCI Dictionary of Cancer Terms