The following glossary was prepared to help the consumer
become familiar with the most common terms used in clinical
trials.
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/.
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.
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 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. (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).
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.
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.
Glossary Sources:
AIDSinfo.Glossary
of HIV/AIDS-Related terms 4th Edition.
CenterWatch, Inc. Patient Resources: Glossary.
ECRI (formerly the Emergency Care Research Institute).
Eli Lilly and Company. Lilly Clinical Trials Glossary.
MediStudy.com Inc. ClinicalTrials: A-Z Glossary.
National Cancer Institute.
Cancer.gov Dictionary.
Source: National Institutes of Health, National Library of
Medicine
