What is a clinical trial?
Clinical trials are
research studies in which people help doctors and researchers find ways to
improve health care. Each study tries to answer scientific questions and to
find better ways to prevent, diagnose, or treat disease.
purpose of a clinical trial is to find out whether a medicine or treatment
regimen is safe and effective for the treatment of a specific condition or
disease. Clinical trials compare the effectiveness of the study medicine or
treatment against standard, accepted treatment, or against a
if no standard treatment exists.
What are the phases of a clinical trial?
medicine or treatment regimen must go through three phases before it is
approved for use by the U.S. Food and Drug Administration (FDA).
- Phase I: A new medicine is tested for the first
time on a small group of healthy people or people with specific conditions or
diseases. Researchers evaluate the safety of the medicine or treatment, the
best dose or schedule to use, and what types of side effects occur. During
phase I trials, all of the people involved in the study (patients, doctors, and
researchers) know what medicine is being used. These are called nonrandomized,
- Phase II: The medicine or treatment is tested on
a larger group of people with specific conditions or diseases. This phase helps
researchers find out how well a medicine or treatment regime will work to treat
a particular problem. Phase II trials are also usually nonrandomized,
- Phase III: The medicine or treatment regimen is
tested on even larger groups. The medicine is studied to find out how well it
works compared with standard treatment or placebo and whether it improves
specific areas in your life, such as how well you are able to keep up with your
usual routine. Most medicines that reach phase III trials will be considered
for FDA approval. During phase III trials, participants receive the study
medicine, a placebo, or the standard treatment. Neither the participants, the
doctors, or the researchers know which person is getting which medicine. These
are called randomized and double-blinded studies.
- Phase IV. Medicines are
also studied after they are approved to find new uses for the medicine,
different ways to administer it, or additional safety information. For example,
a medicine may be studied to see how well it works for a specific population,
such as adults over the age of 65 or a certain racial group.