Clinical Trials

A clinical trial is a type of medical research study that tests an intervention to answer questions concerning the identification, treatment and management of illnesses and disease. An intervention may be a drug, device, procedure or a change in behavior (diet, nutrition or exercise). Clinical trials depend on human volunteers (participants) to answer these questions and improve health.

Clinical trials are carefully conducted and must follow a strict set of rules and regulations, called a protocol. The protocol is designed to protect the safety of the volunteer to the highest degree. Clinical trials must also be approved by an independent committee, called an Institutional Review Board, or IRB, that examines the risks and benefits of the study and determines if risks are reasonable.

Clinical Trial Participation

Find more information about the benefits of participating in clinical trials.

Participation Info

Focus of Clinical Trials

There are different types of clinical trials; they do not always test medicines. Some look at the long-term effects of treatment or the impact of diet, nutrition and exercise on incidence of an illness or disease. Some need volunteers with specific illnesses and some need healthy volunteers. Some examine the effects of a new drug, vaccine or treatment and others examine large populations in natural settings.

Phases of Research

Clinical trials are conducted as part of one of four phases, and each phase has a specific goal.

Phase I

Phase I trials explore how a new medicine or treatment should be given (orally, topically, intravenously) as well as how often and at what dose. Some phase I trials are adding new medicines into known regimens. These trials typically include a small group of patients.

Phase II

Phase II trials may include up to several hundred people further explore the safety and efficacy of a treatment or approach to disease management.

Phase III

Phase III trials may include up to several thousand participants and are focused on gathering more information about the intervention’s safety and effectiveness. After a phase III trial is successfully completed, the FDA will use this data to determine whether to approve the new medication or medical device.

Phase IV

Phase IV trials evaluate the long-term side effects of an FDA-approved treatment.

Patient Participation

Participating in clinical research can make a life-saving difference in the lives of other people with similar conditions. Patient participants may also benefit directly.

Learn more about participation