Definitions of Commonly Used Words in a Clinical Trial

Antibodies – Proteins in the blood which recognize and block foreign substances.

Antiviral – A substance that stops or suppresses the activity of a virus.

Asymptomatic – Infection without symptoms. Someone who is asymptomatic has antibodies to a disease but does not have any visible signs or symptoms of infection.

Clinical Trial – A test of a new or experimental drug in people. Also called drug trials or studies.

Comparison Trial – A trial in which experimental drugs are tested against each other or against on approved drug.

Controlled Trials – Trials in which one group gets the experimental drug and another group gets either a placebo or an approved drug therapy. Participants usually do not know which group they are in.

Crossover – A controlled drug trial in which, halfway through the study, the groups in the trial switch. That is, those taking the experimental drug are given the standard drug and vice versa.

Dose Comparison – Trial that uses different amounts of the same drug. Sometimes the drug is tested against a placebo.

Dose Escalation Trial – In this type of trial, one or a few people, usually under a dozen, take a small amount of the drug. If it doesn’t hurt them, one or a few more take a larger amount. This continues until the researchers find the largest amount of the drug that can be taken without immediate harm.

Double-blind – A type of drug trial in which people are divided into different groups. One group takes the experimental drug and other groups take different doses, the standard therapy, or placebo. Neither the researchers nor the person in the trial know who is taking what until the trial is over.

Immunomodulators – Drug intended to affect the action of the immune system.

Inclusion/exclusion criteria – The medical or other reasons why a person may or may not be allowed to enter a trial. For example, some trials do not allow pregnant women to join, others do not allow people to take certain drugs, and others exclude people with certain illnesses. Other trials may try to include pregnant or nursing women.

IND or Investigational New Drug – The name given to an experimental drug after the FDA agrees that it can be tested in people.

Informed Consent – The name given to the process during which a person weighs the risks and benefits of a trial, then agrees voluntarily to participate. When someone agrees to be in a trial, they sign an agreement called an informed consent form. If new information about a drug becomes known, a participant who has given their informed consent will be told of this information, and asked to consent to continue the trial.

Institutional Review Board (IRB) – Every institution or hospital that conducts research involving human subjects must have an IRB that approves and periodically reviews the research. The IRB protects the rights of the people in the trial, determines who can participate in the trial and whether the trial is ethical.

Open-Label Trial – A type of drug trial in which researchers and participants know who is taking the experimental drug or the treatment being given.

Pharmacokinetic Trials – Trials which study how the drug is absorbed by the body. These trials often require a short stay in the hospital.

Placebo – A substance that has no effect on the body (often referred to as a sugar pill) that is given to one group in a placebo-controlled trial.

Prophylaxis – Taking a drug to prevent yourself from getting an illness.

Protocol – A detailed plan stating a drug trial’s purpose , drug dosages, length of treatment, how the drug is given, and inclusion/exclusion criteria.

Randomized Trial – A trial in which people are assigned to one of two or more treatments by chance. Usually a computer is used to be sure that everyone has the same chance of getting on any given part of the trial.

Short Form Written Consent – A form that states that everything in the informed consent has been verbally explained to an individual entering the trial. A witness must be present when the trial is explained and this form is signed.

Toxicity – Describes some of the possible side effects of a drug. Also indicates how much of a drug can safely be taken.

Treatment IND – An FDA program that makes experimental drugs available to seriously ill people. Drug companies may charge for the drug, although most don’t.

Washout Period – A specified length of time during which active medication is withdrawn from the person entering the trial.