Glossary of Terms for Undertaking a Clinical Drug Trial in the United States

Adherence: The degree to which a participant follows the instructions of the clinical trial protocol.

Adverse event: Any unwanted or unexpected medical occurrence in a participant during a clinical trial, whether or not it is considered related to the investigational drug.

Case report form (CRF): A document used to collect data from participants in a clinical trial. CRFs typically include information on the participant’s demographics, medical history, and current health status.

Clinical investigator: A physician or other healthcare professional who is responsible for conducting a clinical trial.

Clinical trial: A research study that tests the safety and effectiveness of a new drug or medical device in humans. Clinical trials are conducted in four phases, each with a different purpose.

Clinical trial protocol: A document that describes the design and procedures of a clinical trial. The protocol includes information on the eligibility criteria for participants, the investigational drug or device, the procedures that will be performed, and the data that will be collected.

Comparator: The treatment that is compared to the investigational drug in a clinical trial. The comparator may be a standard treatment, a placebo, or another investigational drug.

Compensation: The financial or other benefits that participants may receive for participating in a clinical trial.

Consent form: A document that explains the details of a clinical trial and that participants must sign before they can enroll in the trial. The consent form includes information on the risks and benefits of the trial, the procedures that will be performed, and the participant’s rights.

Control group: The group of participants in a clinical trial who receive the comparator treatment.

Data monitoring committee (DMC): An independent group of experts who monitor the data from a clinical trial to ensure the safety of participants.

Eligibility criteria: The criteria that participants must meet in order to enroll in a clinical trial. Eligibility criteria may include factors such as age, sex, medical history, and current health status.

Informed consent: The process of ensuring that participants understand the risks and benefits of a clinical trial before they enroll. The informed consent process includes reviewing the consent form with participants and answering any questions that they have.

Investigational drug or device: The drug or device that is being tested in a clinical trial.

Investigational new drug (IND) application: An application that pharmaceutical companies must submit to the Food and Drug Administration (FDA) before they can begin testing a new drug in humans. The IND application includes information on the drug’s safety and pharmacology.

Investigator’s brochure (IB): A document that provides detailed information on the investigational drug or device, including its safety and pharmacology. The IB is provided to clinical investigators so that they can understand the drug or device and inform participants of the risks and benefits of the trial.

New drug application (NDA): An application that pharmaceutical companies must submit to the FDA before they can market a new drug in the United States. The NDA includes information on the drug’s safety, efficacy, and manufacturing process.

Placebo: A substance that has no known therapeutic effect. Placebos are often used in clinical trials as a control treatment.

Protocol amendment: A change to the clinical trial protocol. Protocol amendments may be necessary to address unexpected events or to improve the design of the trial.

Randomization: The process of assigning participants to different treatment groups in a clinical trial on a random basis. Randomization helps to ensure that the treatment groups are balanced and that the results of the trial are not biased.

Serious adverse event: An adverse event that results in death, hospitalization, life-threatening illness, or permanent disability.

Site: A location where a clinical trial is conducted. Clinical trials may be conducted at hospitals, universities, and private clinics.

Sponsor: The individual or organization that is responsible for designing, funding, and conducting a clinical trial.

Subject expert committee (SEC): An independent group of experts who review the protocol and data from a clinical trial to provide advice to the sponsor and the FDA.

Unblinding: The process of revealing the treatment assignment to participants and investigators in a clinical trial. Unblinding may be necessary in the event of a serious adverse event or if the results of the trial are clear.

This glossary is not exhaustive, but it includes some of the most common terms used in clinical drug trials in the United States. If you have any questions about a term that is not listed here, please ask your doctor or the clinical investigator.