Understanding Clinical Trials
Joining a clinical trial is one of the many
important decisions
faced by cancer patients and people who are
at high risk of
developing cancer. When considering a
clinical trial, it is
important to gather as much information as
you need and to
take the time to understand it. You need to
weigh the possible
benefits and risks for yourself. You may also
find it helpful to
talk to family or friends, your health-care
providers, and
anyone you know who has been in a clinical
trial.
Understanding Clinical Trials
An Introduction
What Is a Clinical Trial?
What are the Phases of Clinical Trials?
What is a Clinical Trial Protocol?
Where are Trials Conducted?
Who Can Participate in a Trial?
How are Trial Participants Protected?
What Is a Clinical Trial?
Clinical trials are studies that evaluate the
effectiveness of new
interventions. There are different types of
cancer clinical trials.
They include:
prevention trials designed to keep
cancer from
developing in people who have not
previously had
cancer;
prevention trials designed to prevent a
new type
of cancer from developing in people who
have
had cancer;
early detection trials to find cancer,
especially in
its early stages;
treatment trials to test new therapies
in people
who have cancer;
quality of life studies to improve
comfort and
quality of life for people who have
cancer;
studies to evaluate ways of modifying
cancer-causing behaviors, such as
tobacco use.
So, depending on what is being studied, a
particular clinical trial
may involve patients with cancer or people
who do not have
cancer but are at higher risk than most
people for developing it.
If you take part in a clinical trial, you may
benefit from a new
drug, procedure, or symptom-control method
while helping
scientists evaluate its effectiveness. Your
participation may also
contribute directly to finding better ways to
prevent, detect, or
treat the disease. Many of today's most
effective interventions
are the direct result of knowledge gained
through clinical trials.
What Are the Phases of Clinical Trials?
Most clinical research that involves the
testing of a new drug
progresses in an orderly series of steps.
This allows
researchers to ask and answer questions in a
way that expands
our information about the drug and its
effects on people. Based
on what has been learned in laboratory
experiments or
previous trials, researchers formulate
hypotheses or questions
that need to be answered. Then they carefully
design a clinical
trial to test the hypothesis and answer the
research question. It
is customary to separate different kinds of
trials into phases that
follow one another in an orderly sequence.
Generally, a
particular cancer clinical trial falls into
one of three phases.
Phase I Trials
These first studies in people evaluate how a
new drug should
be administered (orally, intravenously, by
injection), how often,
and in what dosage. A Phase I trial usually
enrolls only a small
number of patients.
Phase II Trials
A phase II trial provides preliminary
information about how
well the new drug works and generates more
information about
safety and benefit. Each Phase II study
usually focuses on a
particular type of cancer.
Phase III Trials
These trials compare a promising new drug,
combination of
drugs, or procedure with the current
standard. Phase III trials
typically involve large numbers of people in
doctors' offices,
clinics, and cancer centers nationwide. If
you participate in a
Phase III treatment trial, you are likely be
randomized
(assigned by chance) to a group receiving
either the new
intervention or the standard intervention.
Trials designed in this
way are also called randomized controlled
trials. If you are
assigned the standard intervention, you
receive what experts
view as the best treatment available in the
realm of routine
medical practice. If you are assigned the new
intervention, you
receive a treatment that some experts think
may have significant
advantages over the standard. The reason that
the clinical trial
has been initiated is that the superiority of
one treatment over
the other has not yet been firmly
established.
Some use the term Phase IV to include the
continuing
evaluation that takes place after FDA
approval, when the drug
is already on the market and available for
general use
(post-marketing surveillance).
Some supportive care, prevention, and
screening trials are not
done in phases, but instead compare groups of
people using a
certain anticancer strategy (counseling,
behavior change,
detection method) with those who do not.
What is a Clinical Trial Protocol?
Clinical trials follow strict scientific
guidelines. These guidelines
deal with many areas, including the study's
design, who can be
in the study, and the kind of information
people must be given
when they are deciding whether to
participate. Every trial has a
chief investigator, who is usually a doctor.
The investigator
prepares a study action plan, called a
protocol. This plan
explains what the trial will do, how, and
why. For example, it
states:
How many people will be in the study.
Who is eligible to participate in the
study.
What study drugs participants will take.
What medical tests they will have and
how often.
What information will be gathered.
Every research center that takes part in the
trial uses the same
protocol. This ensures that information from
all centers can be
combined and compared.
Where are Trials Conducted?
If you were to participate in a clinical
trial, you might receive
your treatment at a large cancer center, a
university hospital, or
your local medical center or physician's
office. Depending on
the type of trial and on the approach being
studied in it, the trial
may be treating participants at one or two
highly specialized
centers or at hundreds of locations at the
same time. You
would follow the trial's protocol under the
guidance of a team
including your physician, an oncology nurse,
or other health
professionals, who would report your
experience with the
treatment back to the center responsible for
the trial's overall
coordination. Experts could then use the
information from all
the participants to evaluate the new
treatment, screening
method, or preventive measure under
investigation.
Who Can Participate in a Trial?
Clinical trials enroll people who are alike
in certain ways
depending on the study's purpose. Every
protocol identifies
some specific characteristics that the people
should have in
order to participate in the study. These
characteristics are
called eligibility criteria. They may include
the type of disease
and its stage, age and general health.
Eligibility criteria are a key part of
medical research. They help
assure that the study results answer the
research question. They
also help doctors identify who will benefit
in the future from the
approach being studied if it's shown to work.
For example, in
cancer prevention studies, a new drug may
work for people
with one type of risk factor but not for
another.
Eligibility criteria also help insure safety
of participants by
protecting them from known risks. For
example, some drugs
can only be given safely if a person has
normal kidneys or liver.
In this situation only persons with normal
kidney or liver
function are allowed to participate.
How Are Trial Participants Protected?
Clinical trials have several procedures to
protect the safety of
the people who participate. One or more
review groups have
to approve the protocol for every study. Two
of those groups
are the organization that sponsors it (for
example, the National
Cancer Institute) and the Institutional
Review Board (IRB) that
oversees clinical research in the health-care
institution.
Every study center has an IRB, which includes
doctors, other
health care providers, consumers, and
sometimes members of
the clergy. IRB members do not have any
personal interest in
the results of the study. They serve as
neutral reviewers,
ensuring that the study is conducted fairly
and that no one who
decides to become a participant is likely to
be harmed. Each
Phase III trial also has a special group
called a Data Safety and
Monitoring Committee that looks at the test
results, monitors
the safety of the participants, and decides
whether the study
should go forward as originally planned.
Finding Specific Trials
One of the first places to start is an NCI
database called PDQ.
This section provides a "User's Guide" to
PDQ, which includes
a discussion of how to search the database
for clinical trials,
how to use the information you retrieve, and
other places to
look.
Advances in Cancer Care
Clinical Trials Make a Difference.
Clinical trials are essential to making
progress against cancer.
As trials answer research questions, they
directly affect
people's lives. Better treatments lead to
longer life and
improved quality of life. New screening and
prevention
practices help us discover cancer in its
early, most treatable
stages and offer ways of reducing the chance
of getting cancer.
The following describes a few examples of the
numerous trials
that are helping to make a real difference
against cancer.
HER2 Overexpression Test Recommended with
Caveats
(posted 9/4/98).
Herceptin is Recommended for FDA Approval
(posted 9/2/98).
Tamoxifen For High Risk Women Recommended
for FDA
Approval (posted 9/2/98).
Clinical Trials and Insurance Coverage: A
Resource Guide
(posted 8/31/98).
Novel Therapy to Treat Lung Cancer Patients
(posted 8/12/98).
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