Clinical Trials Glossary


Clinical trial - Investigation of the effects of a drug or other medical therapy on a group of people.

Compassionate use - Regulations that allow people who are extremely ill to obtain investigational treatments before approval.

Control group - A group of healthy patients used for comparison in a clinical trial.

Double-blind - A trial in which neither the patient nor the physician knows whether drug or placebo is being taken, or at what dosage.



Discovery - early stages of research during which compounds are identified as possible targets for drug development.



Fast track - an FDA designation that allows for expedited review of new drugs that are intended to treat serious conditions, and that demonstrate the potential to address unmet medical needs of patients with those conditions.


Food and Drug Administration (FDA) - The government agency that regulates the used of drug manufacture and testing; FDA approval is necessary before people can use a drug.

Informed consent - A discussion of the procedures, risks, and benefits of a clinical trial between the investigator and the patient. All patients must sign the informed consent form before participating in a trial.

Institutional Review Board (IRB) - An IRB exists at each study site, and comprises health care professionals who evaluate all aspects of the trial to ensure that FDA regulations are being met.

Investigational treatment - The drug being tested during the clinical trial.

New Drug Application (NDA) - Sponsors file an NDA with the FDA upon completion of testing, requesting approval to market the drug.

Open-label - A study in which both the participant and the researcher know what drug and dose is being used.

Pharmacokinetics - What happens to a drug when it has been administered: how it is absorbed, distributed, and excreted, from the body.

Phases - Drugs pass through three phases of testing. During Phase I, drugs are tested in healthy subjects to determine safety, and how the drug acts in the body. During Phase II, several hundred people with the disease targeted by the drug are studied, to determine the drug's effectiveness in treating the disease. In Phase III, testing is expanded to several thousand patients, to verify safety, effectiveness, and dosage.

Placebo - A harmless substance that looks identical to the drug on trial.

Placebo-controlled - A trial in which the effectiveness of the drug is compared to that of a placebo.



Preclinical studies - studies that test a compound on animal or other nonhuman models, which provide data on the agent's activity and safety.


Principal Investigator - The medical professional overseeing the treatment of patients at the study site.

Protocol - The guidelines for the trial, usually designed by the sponsor.

Randomized - A trial in which patients are randomly assigned to receive either drug or placebo.

Sponsor - The pharmaceutical company, research institution, or healthcare organization that funds a clinical trial and designs the protocol.

Standard treatment - The FDA-approved treatment that is widely used for a given disease.

Study coordinator - The individual who manages the procedures and conduct of the trial.



For further information, call the Irwin M. and Suzanne R. Rosenthal IBD Resource Center (IBD Help Center): 888.MY.GUT.PAIN (888.694.8872).

The Crohn’s & Colitis Foundation of America provides information for educational purposes only. We encourage you to review this educational material with your health care professional. The Foundation does not provide medical or other health care opinions or services. The inclusion of another organization’s resources or referral to another organization does not represent an endorsement of a particular individual, group, company or product.

About this resource

By: CCFA
Published: May 1, 2012