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Types of clinical trials

Treatment trials test investigational therapies, new medication combinations, and new surgical or radiation therapy methods.

Prevention trials look for better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vaccines, vitamins, minerals, or lifestyle changes.

Diagnostic trials are performed to find better tests or procedures for detecting and diagnosing a particular disease or condition.

Screening trials examine the best way to identify certain diseases or health conditions.

Quality of Life trials investigate method to improve the wellbeing and the quality of life for individuals with a chronic illness.

Phases of Clinical Research Studies

During Phase I studies, a study team gives the treatment to a small number of volunteers and examines its action in the body, its safety and its effects at various doses. Phase 1 studies generally last only a few months.

If results show that the treatment appears safe, it will be tested in Phase II and Phase III clinical studies. These studies involve larger numbers of people over longer periods of time. In these studies, the study team wants to know whether the treatment is safe and effective and what side effects it may have.

After these phases are complete and investigators are satisfied that the treatment is safe and effective, the study team may submit its data to the Food and Drug Administration (FDA) for approval. The FDA reviews the data and decides whether to approve the drug or treatment for use in patients.

A Phase IV study is also known as a post marketing surveillance study. Phase IV studies involve safety surveillance and continuing technical support of a drug after it receives permission to be sold. Phase IV studies may be required by regulatory authorities or may be undertaken by the sponsoring company for finding a new market for the drug or other reasons (such as determining interactions with other drugs, or on testing it certain population groups). The safety surveillance is designed to detect any rare or long-term adverse effects over a much larger patient population and longer time period than was possible during the Phase I-III clinical studies.