Clinical Research Glossary

Common Terms Used in Clinical Trials

Blinded (Masked) Study: Participants do not know whether they are in the experimental or control group in a research study.

Control Group: While one group of study participants receives the experimental therapy, the control group receives either the standard therapy or placebo.

Clinical Investigator: A medical researcher in charge of carrying out a clinical trial’s protocol.

Clinical Trial: The term clinical trial is another way to say clinical research study.

Double-Blinded (Double-Masked) Study: Neither the study participants nor the study professionals know which participants are receiving the test therapy and which participants are receiving standard therapy or placebo.

Confidentiality: Refers to maintaining the confidentiality of trial participants including their personal identity and all personal medical information. The trial participants’ consent to the use of records for data verification purposes should be obtained prior to the trial and assurance must be given that confidentiality will be maintained.

Efficacy: (Of a drug or treatment). The maximum ability of a drug or treatment to produce a result regardless of dosage. A drug passes efficacy trials if it is effective at the dose tested and against the illness for which it is prescribed. In the procedure mandated by the FDA, Phase II clinical trials gauge efficacy, and Phase III trials confirm it.

Inclusion/Exclusion Criteria: The medical or social standards determining whether a person may or may not be allowed to enter a clinical trial. These criteria are based on such factors as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions. It is important to note that inclusion and exclusion criteria are not used to reject people personally, but rather to identify appropriate participants and keep them safe.

Institutional Review Board (IRB): An IRB is an independent committee of physicians, nurses, pharmacists, scientists, ethicists, and community advocates. Every clinical trials conducted in the United States requires IRB approval and monitoring to protect each participant’s rights and welfare.

Phase: Clinical trials of experimental drugs progress through four phases:

  • In Phase I clinical trials, researchers test a new drug or therapy in a small group of participants (20-80) for the first time to evaluate treatment safety, determine proper dosage, and observe side effects.
  • In Phase II clinical trials, researchers administer the study drug or therapy to a larger group of participants (100-300) to further evaluate both its safety and effectiveness.
  • In Phase III clinical trials, researchers administer the study drug or therapy to a larger group of participants (1,000-3,000) to confirm effectiveness, identify risks, monitor side effects, and compare and contrast study treatment safety and effectiveness with commonly used therapies.
  • In Phase IV clinical trials, researchers continue testing the study drug or therapy in order to measure treatment effectiveness and monitor the effects of long-term use.

Placebo: A placebo is an inactive pill, liquid, or powder that has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the treatment’s effectiveness. In some studies, the participants in the control group will receive a placebo instead of an active drug or treatment. No sick participant receives a placebo if there is a known beneficial treatment.

Protocol: A protocol outlines the specifics of the clinical trial, namely, study qualifications, time points, treatments, and procedures.

Side Effects: Side effects are any undesired actions or effects caused by the study drug or therapy.

Standard Treatment: A treatment currently in wide use and approved by the FDA, considered to be effective in the treatment of a specific disease or condition.

Study Coordinator: Study Coordinators are typically members of a research team that are responsible for such things as, recruiting, screening, and enrolling study participants, as well as ensuring the adherence to Good Clinical Practice guidelines.

Subject: A volunteer who participates in a clinical trial, either as a recipient of the experimental treatment, or as a control who receives the standard treatment, or as a healthy volunteer who receives no treatment.

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