The Nuts and Bolts of a Clinical Trial

A clinical trial is a research study designed to answer specific questions about vaccines or new therapies or new ways of using known treatments. Clinical trials are used to determine whether new drugs or treatments are safe and effective. Estimates on the number of research studies range from about 5,000 to 7,000 each year, many at multiple sites.

A protocol describes the parameters for who may participate in the trial; the schedule of tests, procedures, medications and dosages; and the length of the study.

Clinical trials of experimental drugs proceed through four phases. In Phase I clinical trials, researchers test a new drug or treatment for safety in a small group of people (20 to 80). A larger group gets the drug or treatment in Phase II.

In Phase III studies, the drug or treatment is given to large groups of people (1,000 to 3,000) to confirm its effectiveness, monitor side effects, compare it with commonly used treatments and collect information that will allow the drug or treatment to be used safely. Phase IV studies are done after the drug or treatment has been marketed.

Every clinical trial in the United States must be approved and monitored by an Institutional Review Board to make sure the risks are as low as possible and are worth any potential benefits. A review board is an independent committee of physicians, statisticians, community advocates and others that ensures that a clinical trial is ethical and the rights of study participants are protected.

Informed consent is the process of learning the key facts about a clinical trial before one decides whether to participate.

All clinical trials have guidelines about who can get into the program.

Sources: National Institutes of Health; CenterWatch