The following glossary defines the most commonly used
terms used in clinical trials.
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Adverse reaction
(Adverse Event.) An unwanted effect caused by the administration of drugs. Onset
may be sudden or develop over time (See Side effects).
Advocacy and support groups
Organizations and groups that actively support participants and their families
with valuable resources, including self-empowerment and survival tools.
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 (See
Food and Drug Administration)
Arm
Any of the treatment groups in a randomized trial. Most randomized trials have
two "arms," but some have three "arms," or even more. (See Randomized trial).
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Baseline
1. 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. At this reference point, measurable values
such as CD4 count are recorded. Safety and efficacy of a drug are often
determined by monitoring changes from the baseline values.
Bias
When a point of view prevents impartial judgment on issues relating to the
subject of that point of view. In clinical studies, bias is controlled by
blinding and randomization (See Blind and Randomization).
Blind
A randomized trial is "Blind" if the participant is not told which arm of
the trial he is on. A clinical trial is "Blind" if participants are unaware
on whether they are in the experimental or control arm of the study. (See
Single-blind study and
Double-blind study).
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Clinical
Pertaining to or founded on observation and treatment of participants, as
distinguished from theoretical or basic science.
Clinical endpoint
See Endpoint.
Clinical investigator
A medical researcher in charge of carrying out a clinical trial's protocol.
Clinical trial
A clinical trial is a research study to answer specific questions about
vaccines or new therapies or new ways of using known treatments. Clinical
trials (also called medical research and research studies) are used to determine
whether new drugs or treatments are both safe and effective. Carefully conducted
clinical trials are the fastest and safest way to find treatments that work
in people. Trials are in four phases: Phase I tests a new drug or
treatment in a small group; Phase II expands the study to a larger
group of people; Phase III expands the study to an even larger group
of people; and Phase IV takes place after the drug or treatment has
been licensed and marketed. (See Phase I, II, III, and IV Trials).
Cohort
In epidemiology, a group of individuals with some characteristics in common.
Community-based clinical
trial (CBCT)
A clinical trial conducted primarily through primary-care physicians rather
than academic research facilities.
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.
Complementary and
alternative therapy
Broad range of healing philosophies, approaches, and therapies that Western
(conventional) medicine does not commonly use to promote well-being or treat
health conditions. Examples include acupuncture, herbs, etc. Internet Address:
www.nccam.nih.gov
Confidentiality
regarding trial participants
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.
Contraindication
A specific circumstance when the use of certain treatments could be harmful.
Control
A control is the nature of the intervention control.
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. (See Placebo and Standard treatment).
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.
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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.
Dose-ranging study
A clinical trial in which two or more doses of an agent (such as a drug)
are tested against each other to determine which dose works best and is
least harmful.
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. See Blinded study, Single-blind study, and Placebo.
Drug-drug interaction
A modification of the effect of a drug when administered with another drug.
The effect may be an increase or a decrease in the action of either substance,
or it may be an adverse effect that is not normally associated with either
drug.
DSMB
See Data Safety and Monitoring Board.
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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. (See Food and Drug Administration
(FDA), Phase II and III Trials).
Eligibility criteria
Summary criteria for participant selection; includes Inclusion and Exclusion
criteria. (See Inclusion/exclusion criteria)
Empirical
Based on experimental data, not on a theory.
Endpoint
Overall outcome that the protocol is designed to evaluate. Common endpoints
are severe toxicity, disease progression, or death.
Epidemiology
The branch of medical science that deals with the study of incidence and
distribution and control of a disease in a population.
Exclusion/inclusion criteria
See Inclusion/exclusion criteria.
Expanded access
Refers to any of the FDA procedures, such as compassionate use, parallel
track, and treatment IND that distribute experimental drugs to participants
who are failing on currently available treatments for their condition and
also are unable to participate in ongoing clinical trials.
Experimental drug
A drug that is not FDA licensed for use in humans, or as a treatment for
a particular condition (See Off-label use).
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FDA
See Food and Drug Administration.
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. Internet address:
www.fda.gov
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There are no terms beginning with the letter "G".
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Hypothesis
A supposition or assumption advanced as a basis for reasoning or argument,
or as a guide to experimental investigation.
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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.
IND
See Investigational New Drug.
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.
Informed consent document
A document that describes the rights of the study participants, and includes
details about the study, such as its purpose, duration, required procedures,
and key contacts. Risks and potential benefits are explained in the informed
consent document. The participant then decides whether or not to sign the
document. Informed consent is not a contract, and the participant may withdraw
from the trial at any time.
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.
Intent to treat
Analysis of clinical trial results that includes all data from participants
in the groups to which they were randomized (See Randomization) even if they never received
the treatment.
Intervention name
The generic name of the precise intervention being studied.
Interventions
Primary interventions being studied: types of interventions are Drug, Gene
Transfer, Vaccine, Behavior, Device, or Procedure.
Investigational new drug
A new drug, antibiotic drug, or biological drug that is used in a clinical
investigation. It also includes a biological product used in vitro for diagnostic
purposes.
IRB
See Institutional Review Board.
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There are no terms beginning with the letter "J".
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There are no terms beginning with the letter "K".
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There are no terms beginning with the letter "L".
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Masking
The knowledge of intervention assignment.
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Natural history
study
Study of the natural development of something (such as an organism or a
disease) over a period of time.
New Drug Application (NDA)
An application submitted by the manufacturer of a drug to the FDA - after
clinical trials have been completed - for a license to market the drug for
a specified indication.
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Off-label use
A drug prescribed for conditions other than those approved by the FDA.
Open-label trial
A clinical trial in which doctors and participants know which drug or vaccine
is being administered.
Orphan drugs
An FDA category that refers to medications used to treat diseases and conditions
that occur rarely. There is little financial incentive for the pharmaceutical
industry to develop medications for these diseases or conditions. Orphan
drug status, however, gives a manufacturer specific financial incentives
to develop and provide such medications.
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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.
Pharmacokinetics
The processes (in a living organism) of absorption, distribution, metabolism,
and excretion of a drug or vaccine.
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. (See Placebo controlled study).
Placebo controlled study
A method of investigation of drugs in which an inactive substance (the placebo)
is given to one group of participants, while the drug being tested is given
to another group. The results obtained in the two groups are then compared
to see if the investigational treatment is more effective in treating the
condition.
Placebo effect
A physical or emotional change, occurring after a substance is taken or
administered, that is not the result of any special property of the substance.
The change may be beneficial, reflecting the expectations of the participant
and, often, the expectations of the person giving the substance.
Preclinical
Refers to the testing of experimental drugs in the test tube or in animals
- the testing that occurs before trials in humans may be carried out.
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 (See Inclusion/exclusion criteria).
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Quality of life trials (or Supportive Care trials)
Refers to trials that explore ways to improve comfort and quality of life
for individuals with a chronic illness.
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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 (See
Arm).
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. (See Arm and
Placebo).
Risk-benefit ration
The risk to individual participants versus the potential benefits. The risk/benefit
ratio may differ depending on the condition being treated.
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Screening trials
Refers to trials which test the best way to detect certain diseases or health
conditions.
Side effects
Any undesired actions or effects of a drug or treatment. Negative or adverse
effects may include headache, nausea, hair loss, skin irritation, or other
physical problems. Experimental drugs must be evaluated for both immediate
and long-term side effects (See Adverse reaction).
Single-blind study
A study in which one party, either the investigator or participant, is unaware
of what medication the participant is taking (See Blind and Double-blind 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.
Standards of care
Treatment regimen or medical management based on state of the art participant
care.
Statistical significance
The probability that an event or difference occurred by chance alone. In
clinical trials, the level of statistical significance depends on the number
of participants studied and the observations made, as well as the magnitude
of differences observed.
Study endpoint
A primary or secondary outcome used to judge the effectiveness of a treatment.
Study type
The primary investigative techniques used in an observational protocol;
types are Purpose, Duration, Selection, and Timing.
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Toxicity
An adverse effect produced by a drug that is detrimental to the participant's
health. The level of toxicity associated with a drug will vary depending
on the condition which the drug is used to treat.
Treatment IND
IND stands for Investigational New Drug application, which is part of the
process to get approval from the FDA for marketing a new prescription drug
in the U.S. It makes promising new drugs available to desperately ill participants
as early in the drug development process as possible. Treatment INDs are
made available to participants before general marketing begins, typically
during Phase III studies. To be considered for a treatment IND a participant
cannot be eligible to be in the definitive clinical trial.
Treatment trials
Refers to trials which test new treatments, new combinations of drugs, or
new approaches to surgery or radiation therapy.
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There are no terms beginning with the letter "U".
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There are no terms beginning with the letter "V".
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There are no terms beginning with the letter "W".
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There are no terms beginning with the letter "X".
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There are no terms beginning with the letter "Y".
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There are no terms beginning with the letter "Z".
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Source: www.clinicaltrials.gov
Used with permission of the National Library of Medicine.
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