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Glossary of clinical trial
terms
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).
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; also called masked. (See Single Blind Study and
Double Blind Study).
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:
http://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.
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.
DIAGNOSTIC TRIALS:
Refers to trials that are are conducted to find better tests
or procedures for diagnosing a particular disease or
condition. Diagnostic trials usually include people who have
signs or symptoms of the disease or condition being studied.
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; also called double-masked
study. See Blinded Study, Single-Blind Study, and Placebo.
DOUBLE-MASKED STUDY:
See Double-Blind Study.
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.
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).
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:
http://www.fda.gov/.
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.
MASKED:
The knowledge of intervention assignment. See
Blind
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.
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.
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 an 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).
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 RATIO:
The risk to individual participants versus the potential
benefits. The risk/benefit ratio may differ depending on the
condition being treated.
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; also called single-masked study. (See Blind
and Double-Blind Study).
SINGLE-MASKED STUDY:
See Single-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.
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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