Clinical Trials Research FAQs
Common Clinical Research Questions
What is a clinical trial?
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.
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Why participate in a clinical trial?
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.
Who can participate in a clinical trial?
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.
What happens during a clinical trial?
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 the protocol is carefully followed and there is
frequent contact with the research staff.
What is informed consent?
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.
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.
However, 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.
What are side effects and adverse reactions?
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.
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 Trial Participants).
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 is the purpose of the study?
- Who is going to be in the study?
- Why do researchers believe the experimental treatment being tested may
- 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?
What kind of preparation should a potential participant make for the meeting
with the research coordinator or doctor?
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 United States 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 has begun?
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 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.
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 clinics.
What is a protocol?
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.
What is a 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 experimental treatment's effectiveness. In some studies,
the participants in the control group will receive a placebo instead of
an active drug or experimental treatment.
What is a control or control group?
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.
What are the different types of clinical trials?
Treatment trials test experimental treatments, new combinations of drugs or new approaches
to surgery or radiation therapy.
Prevention trials look for 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.
Diagnostic trials are conducted to find better tests or procedures for diagnosing a particular
disease or condition.
Screening trials 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.
What are the phases of clinical trials?
Clinical trials are conducted in phases. The trials at each phase have
a different purpose and help scientists answer different questions:
Phase I trials, researchers 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 side effects.
Phase II trials, the 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.
Phase III trials, the 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.
Phase IV trials, post marketing studies delineate additional information including the
drug's risks, benefits and optimal use.
What is an "expanded access" protocol?
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
regulations 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
ClinicalTrials.gov, review the protocol eligibility criteria and location information and
inquire at the contact information number.