Glossary of Clinical Trials Terms

Adverse Reaction:

(Adverse Event.) An unwanted effect caused by the administration of drugs. Onset may be sudden or develop over time.

Adverse Reaction:

(Adverse Event.) An unwanted effect caused by the administration of drugs. Onset may be sudden or develop over time.

Approved Drugs:

In the U.S., the Food and Drug Administration (FDA) must approve a substance as a drug before it can be marketed. The approval process involves several steps including pre-clinical laboratory and animal studies, clinical trials for safety and efficacy, filing of a New Drug Application by the manufacturer of the drug, FDA review of the application, and FDA approval/rejection of application.

Arm:

Any of the treatment groups in a randomized trial. Most randomized trials have two "arms," but some have three "arms," or even more.

Baseline:

Information gathered at the beginning of a study from which variations found in the study are measured. 2. A known value or quantity with which an unknown is compared when measured or assessed. 3. The initial time point in a clinical trial, just before a participant starts to receive the experimental treatment which is being tested. Safety and efficacy of a drug are often determined by monitoring changes from the baseline values.

Blind:

A randomized trial is "Blind" if the participant is not told which arm of the trial he or she is on. A clinical trial is "Blind" if participants are unaware on whether they are in the experimental or control arm of the study; also called masked.

Clinical Investigator:

A medical researcher in charge of carrying out a clinical trial's protocol.

Compassionate Use:

A method of providing experimental therapeutics prior to final FDA approval for use in humans. This procedure is used with very sick individuals who have no other treatment options. Often, case-by-case approval must be obtained from the FDA for "compassionate use" of a drug or therapy.

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.

Control Group:

The standard by which experimental observations are evaluated. In many clinical trials, one group of patients will be given an experimental drug or treatment, while the control group is given either a standard treatment for the illness or a placebo.

Controlled Trials:

Control is a standard against which experimental observations may be evaluated. In clinical trials, one group of participants is given an experimental drug, while another group (i.e., the control group) is given either a standard treatment for the disease or a placebo.

Data Safety And Monitoring Board (DSMB):

An independent committee, composed of community representatives and clinical research experts, that reviews data while a clinical trial is in progress to ensure that participants are not exposed to undue risk. A DSMB may recommend that a trial be stopped if there are safety concerns or if the trial objectives have been achieved.

Double-Blind Study:

A clinical trial design in which neither the participating individuals nor the study staff knows which participants are receiving the experimental drug and which are receiving a placebo (or another therapy). Double-blind trials are thought to produce objective results, since the expectations of the doctor and the participant about the experimental drug do not affect the outcome; also called double-masked study.

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.

Eligibility Criteria:

Summary criteria for participant selection; includes Inclusion and Exclusion criteria.

Epidemiology:

The branch of medical science that deals with the study of incidence and distribution and control of a disease in a population.

Food and Drug Administration (FDA):

The U.S. Department of Health and Human Services agency responsible for ensuring the safety and effectiveness of all drugs, biologics, vaccines, and medical devices, including those used in the diagnosis, treatment, and prevention of HIV infection, AIDS, and AIDS-related opportunistic infections. The FDA also works with the blood banking industry to safeguard the nation's blood supply.

Hypothesis:

A supposition or assumption advanced as a basis for reasoning or argument, or as a guide to experimental investigation.

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.

Informed Consent:

The process of learning the key facts about a clinical trial before deciding whether or not to participate. It is also a continuing process throughout the study to provide information for participants. To help someone decide whether or not to participate, the doctors and nurses involved in the trial explain the details of the study.

Institutional Review Board (IRB):

1. A committee of physicians, statisticians, researchers, community advocates, and others that ensures that a clinical trial is ethical and that the rights of study participants are protected. All clinical trials in the U.S. must be approved by an IRB before they begin. 2. Every institution that conducts or supports biomedical or behavioral research involving human participants must, by federal regulation, have an IRB that initially approves and periodically reviews the research in order to protect the rights of human participants.

Open-Label Trial:

A clinical trial in which doctors and participants know which drug or vaccine is being administered.

Peer Review:

Review of a clinical trial by experts chosen by the study sponsor. These experts review the trials for scientific merit, participant safety, and ethical considerations.

Phase I Trials:

Initial studies to determine the metabolism and pharmacologic actions of drugs in humans, the side effects associated with increasing doses, and to gain early evidence of effectiveness; may include healthy participants and/or patients.

Phase II Trials:

Controlled clinical studies conducted to evaluate the effectiveness of the drug for a particular indication or indications in patients with the disease or condition under study and to determine the common short-term side effects and risks.

Phase III Trials:

Expanded controlled and uncontrolled trials after preliminary evidence suggesting effectiveness of the drug has been obtained, and are intended to gather additional information to evaluate the overall benefit-risk relationship of the drug and provide and adequate basis for physician labeling.

Phase IV Trials:

Post-marketing studies to delineate additional information including the drug's risks, benefits, and optimal 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.

Prevention Trials:

Refers to trials to find better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vitamins, vaccines, minerals, or lifestyle changes.

Protocol:

A study plan on which all clinical trials are based. The plan is carefully designed to safeguard the health of the participants as well as answer specific research questions. A protocol describes what types of people may participate in the trial; the schedule of tests, procedures, medications, and dosages; and the length of the study. While in a clinical trial, participants following a protocol are seen regularly by the research staff to monitor their health and to determine the safety and effectiveness of their treatment.

Randomization:

A method based on chance by which study participants are assigned to a treatment group. Randomization minimizes the differences among groups by equally distributing people with particular characteristics among all the trial arms. The researchers do not know which treatment is better. From what is known at the time, any one of the treatments chosen could be of benefit to the participant.

Randomized Trial:

A study in which participants are randomly (i.e., by chance) assigned to one of two or more treatment arms of a clinical trial. Occasionally placebos are utilized.

Screening Trials:

Refers to trials which test the best way to detect certain diseases or health conditions.

Single-Blind Study:

A study in which one party, either the investigator or participant, is unaware of what medication the participant is taking; also called single-masked study.

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.

Study Type:

The primary investigative techniques used in an observational protocol; types are Purpose, Duration, Selection, and Timing.

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.

Treatment Trials:

Refers to trials which test new treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.

Glossary Source:

National Institutes of Health (NIH)