The Clinical Trials Process

Clinical trials are designed to advance scientific knowledge while protecting the people who volunteer to participate. Duke’s researchers must follow specific regulations to ensure patients’ safety and privacy.

Lab Testing

Before a new therapy, device, or procedure is tested on humans, it is tested in a research lab and on animals. If it shows promise, it moves through a staged approach in what are called phases.

Clinical Trial Phases

Clinical trials are performed in the following phases.

  • Phase I: Tests a new therapy for the first time in a small group of people to determine if it is safe, find the right dose, and learn about side effects.
  • Phase II: Involves more people to determine how well the new therapy treats a disease and whether the treatment is safe.
  • Phase III: Broadens the study to include large groups of people to determine if the new therapy works well, if it has side effects, and how it compares to other therapies.
  • Phase IV: Once the treatment is approved by the U.S. Food and Drug Administration (FDA), these studies evaluate the effects of new drugs and treatments over a long period of time in large groups. They are often focused on particular groups such as people of specific ages, genders, or races, or people who are taking other medications or have other diseases.

Clinical Trial Protocols

The clinical trial protocol maps out the criteria for participation, schedule of procedures and treatments, and length of the study.

Randomized Clinical Trials

People who volunteer for clinical trials are often assigned randomly (like the flip of a coin) to receive one treatment or another, hence the name "randomized clinical trials." People who agree to join the study will be randomly assigned to one of the treatments being studied. When no standard treatment is available, some people may be randomly assigned to receive an inactive treatment referred to as a "placebo." Placebos may also be part of a study to help determine whether a therapy has a significant “placebo effect,” meaning some people respond well when they think they are receiving treatment but are not.

Blinded Clinical Trials

Blinded clinical trials are studies in which the participants are randomly assigned to receive one of two or more therapies, but participants and/or researchers are kept unaware of who is receiving which therapy. In single-blinded clinical trials, only one group -- either participants or researchers -- is unaware of who is receiving which therapy; in double-blinded clinical trials, neither participants nor researchers know. 

The information is revealed if it is necessary for your safety to identify what treatment you are receiving. It is also often (but not always) revealed once the study is completed.

Duke’s Institutional Review Board (IRB)

The IRB reviews and approves the protocol, consent form, and all other documents for each study. Its main job is to ensure the study participants are protected and that the balance of potential risks and benefits is appropriate. The IRB conducts regular reviews of each active study.

Contact the Duke Recruitment Innovation Center
This page was medically reviewed on 04/13/2023 by