A clinical trial (also clinical
research) is a research study in human volunteers to answer specific health
questions. Carefully conducted clinical trials are the fastest and safest way to
find treatments that work in people and ways to improve health. Interventional
trials determine whether experimental treatments or new ways of using known
therapies are safe and effective under controlled environments. Observational
trials address health issues in large groups of people or populations in natural
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. 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
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 the protocol 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 that 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.
Q & A:
What are the benefits and risks of participating
in a clinical trial?
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.
What are side effects and adverse reactions?
- There may be unpleasant, serious or even
life-threatening side effects to treatment.
- The treatment may not be effective for the
- 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 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.
How is the safety of the participant protected?
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
What should people consider before participating
in a trial?
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 kind of preparation should a potential
participant make for the meeting with the research coordinator or doctor?
- What is the purpose of the study?
- Who is going to be in the study?
- Why do researchers believe the new treatment
being tested may be effective? Has it been tested before?
- What kinds of tests and 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 treatment?
- Will I be reimbursed for other expenses?
- What type of long-term follow up care is part of
- How will I know that the 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 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.
Does a participant continue to work with a
primary health care provider while in a trial?
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 protocol.
Can a participant leave a clinical trial after it
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.
Where do the ideas for trials come from?
Ideas for clinical trials usually come from researchers. After researchers test
new therapies or procedures in the laboratory and in animal studies, the
treatments with the most promising laboratory results are moved into clinical
trials. During a trial, more and more information is gained about a new
treatment, its risks and how well it may or may not work.
Who sponsors clinical trials?
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 community