A full scale clinical trial to determine drug efficacy and safety prior to seeking marketing approval
a clinical study that examines the new drug's efficacy and safety in a large number of patients suffering from the disease (1000 to 5000 patients). Physicians administer the new drug to patients that meet a set of criteria. These patients are closely monitored to confirm efficacy and safety and to identify adverse events.
a large clinical trial of a treatment or drug that in phase I and phase II has been shown to be efficacious with tolerable side effects; after successful conclusion of phase III clinical trials it will receive formal approval from the FDA