Respuesta :
The main objective of phase 3 trials is to verify the therapeutic action of a new substance in a large number of patients, essentially to determine the risk/benefit ratio. Before phase 3, the substance is not regarded as a drug, but after a positive phase 3 trial it becomes a drug.
Phase III trials compare a new drug to the standard-of-care drug. These trials assess the side effects of each drug and which drug works better. Phase III trials enroll 100 or more patients. Often, these trials are randomized.