This web site was copied prior to January 20, 2005. It is now a Federal record managed by the National Archives and Records Administration. External links, forms, and search boxes may not function within this collection.
Most clinical trials are designated as phase I, II, or III, based on the type of questions that study is
seeking to answer:
In Phase I clinical trials, researchers test a new drug or treatment
in a small group of people (20-80) for the first time to evaluate
its safety, determine a safe dosage range, and identify side effects.
In Phase II clinical trials, the study drug or treatment is
given to a larger group of people (100-300) to see if it is effective
and to further evaluate its safety.
In Phase III studies, the study drug or treatment is given to
large groups of people (1,000-3,000) to confirm its effectiveness,
monitor side effects, compare it to commonly used treatments,
and collect information that will allow the drug or treatment
to be used safely.
These phases are defined by the Food and Drug Administration in the Code of
Click the check box to the left of each study phase that you wish to include in your search. Select
one or more study phases. If you do not select a specific phase, trials in any phase that match your
other search terms will be retrieved.