The Types of Clinical Trials

mother and daughter smilingBefore a new drug, surgical procedure, or therapy becomes available to the

public, it must go through a rigorous testing process and be evaluated by the US
Food and Drug Administration (FDA). This testing process consists of a series of
clinical trials that are designed to test the safety and usefulness of the new
drug compared to the current standard treatment.

The clinical trials that make headlines are usually what are called phase III
trials. These are large-scale tests with hundreds or thousands of patients. They
are the culmination of earlier phase I and phase II trials that include many
fewer people and still earlier preclinical experiments with animals. They are
also the final tests in humans before the FDA is asked to authorize sale of new

Why Are Large-Scale Trials

Clinical trials are designed to test whether a drug is safe for humans, and
whether the drug is effective in treating human diseases or conditions. Although
the drug has generally gone through extensive animal testing before the trial
begins, animal trials cannot always predict how new medicines will affect
humans. Even the most painstaking tests with animals give only approximate
indications of how people will respond to drugs. At some point, after thorough
study in animals (and when the FDA is convinced human experimentation will
probably be safe), tests with humans become necessary.