A computer randomly assigns participants to each group. Whether the experimental treatment will work better than the standard treatment must be proved. The new therapy may have some side effects which your doctor will discuss with you before you enter the trial. There are three phases of clinical trials in which treatments are studied before they are eligible for approval by the Food and Drug Administration. The purpose of a Phase I study is to find the best way to give a new treatment, and how much of it can be given safely.
Physicians watch patients carefully for any side effects.
While treatments tested in a Phase I study have been well tested in laboratory and animal studies, the side effects in patients are not completely predictable. Phase II trials determine the effectiveness of a research treatment after safety has been evaluated in a Phase I trial. Doctors closely observe patients for an anti-cancer effect by carefully measuring cancer sites present at the beginning of the trial. In addition to monitoring patients for response, any side effects are carefully recorded and assessed. Phase III trials require a large number of patients, sometimes thousands.