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Before a new medication can be prescribed or sold over the counter it
must be approved by the Food and Drug Administration or FDA. In order
for the FDA to approve a medication, the pharmaceutical company must
show that the medication is both safe and effective for use in the
treatment for which it is intended. To show this efficacy and safety
the pharmaceutical company will spend many years conducting a series of
studies. The clinical testing of experimental drugs is normally done in
three phases, each successive phase involving a larger number of
people. Once the FDA has granted a New Drug Approval (NDA),
pharmaceutical companies also conduct post marketing or late phase
three/phase four studies.
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A Phase One Study:
Phase I studies are primarily concerned with assessing the drug's
safety. This initial phase of testing in humans is done in a small
number of healthy volunteers (20 to 100), who are usually paid for
participating in the study. The study is designed to determine what
happens to the drug in the human body--how it is absorbed, metabolized,
and excreted. A phase I study will investigate side effects that occur
as dosage levels are increased. This initial phase of testing typically
takes several months. About 70 percent of experimental drugs pass this
initial phase of testing.
A Phase Two Study:
Once a drug has been shown to be safe, it must be tested for
efficacy. This second phase of testing may last from several months to
two years, and involve up to several hundred patients. Most phase II
studies are randomized trials. One group of patients will receive the
experimental drug, while a second "control" group will receive a
standard treatment or placebo. Often these studies are
"blinded"--neither the patients nor the researchers know who is getting
the experimental drug. In this manner, the study can provide the
pharmaceutical company and the FDA comparative information about the
relative safety of the new drug, and its effectiveness. Only about
one-third of experimental drugs successfully complete both phase I and
phase II studies.
A Phase Three Study:
In a phase III study, a drug is tested in several hundred to several
thousand patients. This large-scale testing provides the pharmaceutical
company and the FDA with a more thorough understanding of the drug's
effectiveness, benefits, and the range of possible adverse reactions.
Most phase III studies are randomized and blinded trials.
Phase III studies typically last several years. Seventy to 90 percent
of drugs that enter phase III studies successfully complete this phase
of testing. Once a phase III study is successfully completed, a
pharmaceutical company can request FDA approval for marketing the drug.
Post-Marketing -- Late Phase Three/Phase Four Studies
In late phase III/phase IV studies, pharmaceutical companies have
several objectives: (1) studies often compare a drug with other drugs
already in the market; (2) studies are often designed to monitor a
drug's long-term effectiveness and impact on a patient's quality of
life; and (3) many studies are designed to determine the
cost-effectiveness of a drug therapy relative to other traditional and
new therapies.
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Should you participate in clinical research? |
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People participate in clinical research for a variety of reasons.
People who volunteer for phase II and phase III trials can gain access
to promising drugs long before these compounds are approved for the
marketplace. They typically will get excellent care from the physicians
during the course of the study. This care also may be free.
The patient's rights and safety are protected in ...
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Read more...
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Other questions to ask include: |
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How long will the trial last? |
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Where is the trial being conducted? |
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What treatments will be used and how? |
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What is the main purpose of the trial? |
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How will patient safety be monitored? |
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Are there any risks involved? |
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What are the possible benefits? |
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What are the alternative treatments besides the one being tested in the trial? |
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Who is sponsoring the trial? |
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Do I have to pay for any part of the trial? |
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What happens if I am harmed by the trial? |
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Can I opt to remain on this treatment, even after termination of the trial? |
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Where can you get more information about clinical research? |
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More information about clinical research |
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