CHEM 121 glossary
Clinical trial
A study of a drug in people. Phase I (about 20–100, often healthy volunteers) tests safety and dosage; Phase II (a few hundred patients) tests efficacy and side effects; Phase III (hundreds to thousands) compares the drug with the standard treatment or a placebo; Phase IV monitors it after approval.
Example
A trial in which 3000 patients are randomly assigned either the new drug or the current best treatment, without knowing which they receive, is a Phase III trial.