Choosing to participate in a clinical trial is an important personal decision.
The following frequently asked questions provide detailed
information about clinical trials. In addition, it is often helpful to talk
to a physician, family members, or friends about deciding to join a trial.
After identifying some trial options, the next step is to contact the
study research staff and ask questions about specific trials.
Although there are many definitions of clinical trials, they are
generally considered to be biomedical or health-related research studies
in human beings that follow a pre-defined protocol.
ClinicalTrials.gov includes both interventional and observational types of studies.
Interventional studies are those in which the research subjects are assigned by
the investigator to a treatment or other intervention, and their outcomes are
measured. Observational studies are those in which individuals are observed
and their outcomes are measured by the investigators.
Participants in clinical trials can play a more active role in their own health care,
gain access to new research treatments before they are widely available,
and help others by contributing to medical research.
All clinical trials have guidelines about who can participate.
Using inclusion/exclusion criteria
is an important
principle of medical research that helps to produce reliable results. The
factors that allow someone to participate in a clinical trial are called "inclusion
criteria" and those that disallow someone from participating are called "exclusion
criteria". These criteria are based
on such factors as age, gender, the type and stage of a disease, previous
treatment history, and other medical conditions. Before joining a clinical
trial, a participant must qualify for the study. Some research studies seek participants with illnesses or
conditions to be studied in the clinical trial, while others need healthy participants.
It is important to note that inclusion and exclusion criteria are not used to
reject people personally. Instead, the criteria are used to identify
appropriate participants and keep them safe. The criteria help ensure that
researchers will be able to answer the questions they plan to study.
The clinical trial process depends on the kind of trial
being conducted (See What are the different types of clinical trials?
The clinical trial team includes doctors and nurses as
well as social workers and other health care professionals. They check the
health of the participant at the beginning of the trial, give specific
instructions for participating in the trial, monitor the participant carefully
during the trial, and stay in touch after the trial is completed.
Some clinical trials involve more tests and doctor visits than the participant
would normally have for an illness or condition. For all types of trials, the participant
works with a research team. Clinical trial participation is most successful when
is carefully followed
and there is frequent contact with the research staff.
Informed consent is 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. If the participant's native language is
not English, translation assistance can be provided. Then the research team provides
an informed consent document
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.
Clinical trials that are well-designed and well-executed are the best approach
for eligible participants to:
- Play an active role in their own health care.
- Gain access to new research treatments before they are widely available.
- Obtain expert medical care at leading health care facilities during the trial.
- Help others by contributing to medical research.
There are risks to clinical trials.
- There may be unpleasant, serious or even life-threatening side effects to experimental treatment.
- The experimental treatment may not be effective for the participant.
- The protocol may require more of their time
and attention than would a non-protocol treatment, including trips to the study site, more treatments,
hospital stays or complex dosage requirements.
Side effects are any undesired actions or effects of the experimental drug or
treatment. Negative or adverse effects may include headache, nausea, hair loss,
skin irritation, or other physical problems. Experimental treatments must be
evaluated for both immediate and long-term side effects.
The ethical and legal codes that govern medical practice also apply to clinical trials. In addition,
most clinical research is federally regulated with built in safeguards to protect the participants.
The trial follows a carefully controlled protocol, a study plan which details what researchers will do
in the study. As a clinical trial progresses, researchers report the results of the trial at scientific
meetings, to medical journals, and to various government agencies. Individual participants' names will
remain secret and will not be mentioned in these reports
(See Confidentiality Regarding Trial Participants
People should know as much as possible about the clinical trial and feel comfortable
asking the members of the health care team questions about it, the care expected
while in a trial, and the cost of the trial. The following questions might be helpful
for the participant to discuss with the health care team. Some of the answers to these
questions are found in the informed consent document.
- What is the purpose of the study?
- Who is going to be in the study?
- Why do researchers believe the experimental treatment being tested may be effective? Has it been tested before?
- What kinds of tests and experimental treatments are involved?
- How do the possible risks, side effects, and benefits in the study compare with my current treatment?
- How might this trial affect my daily life?
- How long will the trial last?
- Will hospitalization be required?
- Who will pay for the experimental treatment?
- Will I be reimbursed for other expenses?
- What type of long-term follow up care is part of this study?
- How will I know that the experimental treatment is working? Will results of the trials be provided to me?
- Who will be in charge of my care?
- Plan ahead and write down possible questions to ask.
- Ask a friend or relative to come along for support and to hear the responses to the questions.
- Bring a tape recorder to record the discussion to replay later.
Every clinical trial in the U.S. must be approved and monitored by an
Institutional Review Board (IRB)
to make sure the risks are as low as possible and are worth any potential benefits.
An IRB is an independent committee of physicians, statisticians, community advocates,
and others that ensures that a clinical trial is ethical and the rights of study
participants are protected. All institutions that conduct or support biomedical
research involving people must, by federal regulation, have an IRB that initially
approves and periodically reviews the research.
Yes. Most clinical trials provide short-term treatments
related to a designated illness or condition, but do not provide extended or
complete primary health care. In addition, by having the health care provider
work with the research team, the participant can ensure that other medications
or treatments will not conflict with the
Yes. A participant can leave a clinical trial, at any time.
When withdrawing from the trial, the participant should let the research team
know about it, and the reasons for leaving the study.
Ideas for clinical trials usually come from researchers. After researchers test
new therapies or procedures in the laboratory and in animal studies, the experimental
treatments with the most promising laboratory results are moved into clinical trials.
During a trial, more and more information is gained about an experimental treatment,
its risks and how well it may or may not work.
Clinical trials are sponsored or funded by a variety of organizations or individuals
such as physicians, medical institutions, foundations, voluntary groups, and pharmaceutical
companies, in addition to federal agencies such as the National Institutes of Health (NIH),
the Department of Defense (DOD), and the Department of Veteran's Affairs (VA). Trials can
take place in a variety of locations, such as hospitals, universities, doctors' offices, or
A protocol is 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.
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 experimental treatment's effectiveness. In some studies, the participants
in the control group
a placebo instead of an active drug or experimental treatment.
A control is 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.
test experimental treatments, new combinations of drugs, or new approaches to
surgery or radiation therapy.
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, vaccines, vitamins,
minerals, or lifestyle changes.
to find better tests or procedures for diagnosing a particular disease or condition.
test the best
way to detect certain diseases or health conditions.
Quality of Life trials
(or Supportive Care trials) explore ways to improve comfort and the quality of
life for individuals with a chronic illness.
Clinical trials are conducted in phases. The trials at each phase have a different
purpose and help scientists answer different questions:
In Phase I trials
test an experimental drug or treatment in a small group of people (20-80) for the
first time to evaluate its safety, determine a safe dosage range, and identify
In Phase II trials
experimental study drug or treatment is given to a larger group of people
(100-300) to see if it is effective and to further evaluate its safety.
In Phase III trials
experimental study drug or treatment is given to large groups of people
(1,000-3,000) to confirm its effectiveness, monitor side effects, compare it
to commonly used treatments, and collect information that will allow the
experimental drug or treatment to be used safely.
In Phase IV trials
marketing studies delineate additional information including the drug's risks,
benefits, and optimal use.
Most human use of investigational new drugs
takes place in controlled clinical trials
conducted to assess safety and efficacy
of new drugs.
Data from the trials can serve as the basis for the drug marketing application.
Sometimes, patients do not qualify for these carefully-controlled trials
be cause of other health problems, age, or other factors. For patients who
may benefit from the drug use but don't qualify for the trials, FDA
regu lations enable manufacturers of investigational new drugs to provide for
"expanded access" use of the drug. For example, a treatment IND
(Investigational New Drug application) or treatment protocol is a relatively
unrestricted study. The primary intent of a treatment IND/protocol is to
provide for access to the new drug for people with a life-threatening or
serious disease for which there is no good alternative treatment. A
secondary purpose for a treatment IND/protocol is to generate additional
information about the drug, especially its safety. Expanded access
protocols can be undertaken only if clinical investigators are actively
studying the experimental treatment in well-controlled studies, or all studies have
been completed. There must be evidence that the drug may be an effective
treatment in patients like those to be treated under the protocol. The drug
cannot expose patients to unreasonable risks given the severity of the
disease to be treated.
Some investigational drugs are available from pharmaceutical manufacturers
through expanded access programs listed in ClinicalTrials.gov
Expanded access protocols are generally managed by the manufacturer, with the
investigational treatment administered by researchers or doctors in
office-based practice. If you or a loved one are interested in treatment
with an investigational drug under an expanded access protocol listed in
, review the protocol
information and inquire at the Contact Information number.
See "FDA Finds New Ways to Speed Treatments to Patients" for more details. Link to: