Participating in Clinical Trials

About Clinical Trials

A Research Study With Human Subjects

A clinical trial is a research study that involves human subjects. The purpose of a clinical trial is to find out if an experimental drug, therapy, medical device, lifestyle change, or test will help treat, find, or prevent a disease. A clinical trial may compare experimental products or tests to those already available or may compare existing treatments with each other in order to determine which one is safer or more effective.

The five main types of clinical trials are treatment, screening, diagnostic, prevention, and supportive care trials.

Treatment Trials

In treatment trials, researchers may

Scientists usually do years of experiments in the laboratory and in animals before they even consider testing an experimental treatment in people. Most of this early research occurs at universities and medical centers across the country. The National Institutes of Health funds much of this basic research.

Screening Trials

In screening trials, researchers study ways of finding a disease before symptoms occur. These methods, often called screening tests, can include

Diagnostic Trials

In diagnostic trials, researchers evaluate new tests that could identify a disease in its early stages. Usually, trial participants must show signs of the disease or condition before they can join this type of trial.

Prevention Trials

In prevention trials, researchers study ways to reduce the risk of getting a disease or a specific medical problem. These trials find out if

Supportive Care Trials

In supportive care trials, researchers look for ways to make life better for people living with a life threatening disease or chronic health problem. The goal may be to maximize comfort or to manage side effects of treatment. Researchers may study the role of caregivers, support groups, and various types of social interventions. Supportive care interventions are not intended to treat or cure a disease.

Phases of Clinical Trials

Clinical trials of drugs are usually described based on their phase. The U.S. Food and Drug Administration typically requires Phase 1, 2 and 3 trials to be conducted to determine if the drug can be approved for use.