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Home > Health Library > Clinical Trials
Clinical trials are research studies in which people help doctors find ways to improve health care. Each study tries to find better ways to prevent, diagnose, or treat health problems.
The purpose of a clinical trial is to find out whether a medicine or treatment is safe and effective for treating a certain condition or disease. Clinical trials show how effective this medicine or treatment is compared with standard, accepted treatment. Or they may compare a treatment to a placebo, if there is no standard treatment.
Taking part in a clinical trial is voluntary. No one can make you participate. If you choose not to take part, you will be offered the standard treatment for your health problem. You can talk to your doctor if you have questions about clinical trials.
Clinical trials are important because they allow researchers to find out if a new treatment works as well as or better than accepted treatments. The new treatment might have fewer or less serious side effects. Or the new treatment might not work as well or might cause more side effects than standard treatments.
Clinical trials help drug companies make medicines that are safer and more effective with fewer side effects. Clinical trials also help these companies decide whether to seek approval from the U.S. Food and Drug Administration (FDA) for a certain medicine. If a medicine doesn't work as well as standard treatment, then the FDA isn't likely to approve it.
Clinical trials are also important in finding treatments if no standard treatment exists.
Taking part in a clinical trial may not benefit you directly. But in the future it may help other people who have the same disease.
Your doctor will help you find out if you are eligible to take part in a clinical trial. The company sponsoring the trial will have a very strict set of standards, or criteria, that all participants must meet.
If you meet the criteria, you may be "randomized" to get either the new medicine, a medicine that is considered standard therapy, or a placebo. That means that a computer is used to randomly assign you to one of the treatments. In many studies, neither you nor your doctor knows which treatment you are getting. But not all clinical trials randomize people.
If you have a serious disease, such as cancer, you will not be given only a placebo, unless no effective treatment is known.
After you are accepted by the clinical trial, you can give your consent to take part. After that:
Doctors, nurses, social workers, and other health professionals may be part of your treatment team.
Be sure to carefully follow instructions. If you don't know what you are supposed to do next, call your doctor. Or call the person responsible for your trial.
A medicine or treatment must go through three phases before it is approved for use by the FDA. A fourth phase happens after the medicine or treatment has been approved.
A new medicine is tested for the first time on a small group of healthy people or people with certain conditions or diseases. Researchers check the safety of the medicine or treatment, the best dose or schedule to use, and what types of side effects occur. During this phase, all the people involved in the study (patients, doctors, and researchers) know what medicine is being used. These are called nonrandomized, nonblinded studies.
The medicine or treatment is tested on a larger group of people with certain conditions or diseases. This phase helps researchers find out how well a medicine or treatment will work to treat a particular problem. Phase II trials are also usually nonrandomized, nonblinded studies.
The medicine or treatment is tested on even larger groups. The medicine is studied to find out how well it works compared with standard treatment or placebo. Researchers also study whether the medicine improves specific areas in your life, such as how well you are able to keep your usual routine. Most medicines that reach this phase 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, nor the researchers know which person is getting which medicine. These are called randomized and double-blinded studies.
Medicines are also studied after they are approved. These studies can find new uses for the medicine, different ways to give it, or more safety information. For example, a medicine may be studied to see how well it works for a certain population, such as adults over the age of 65 or a certain racial group.
New combinations of approved medicines can be studied in phase II, phase III, or phase IV trials.
After a clinical trial is completed and the results are studied, the FDA decides whether to approve continued development of the medicine. If the medicine that you received remains in development, you may be able to get more doses as an extension of the study.
If the results of the clinical trial show that the new medicine or combination of medicines works much better than standard treatment, the new medicine may become available to the general public.
Your treatment team may continue to check on you after your trial is over.
You should be fully informed about the possible risks of the trial before you agree to participate.
Every clinical trial in the United States must be approved and monitored by an institutional review board (IRB). This makes sure that the risks are as low as possible and are worth any potential benefits.
The ethical and legal rules for medical practice also apply to clinical trials. Most clinical research is regulated by the U.S. government, with specific rules to protect the participants. Clinical trials follow a carefully controlled study plan (protocol) that explains what everyone will do in the study. During the clinical trial, researchers report the results of the trial at scientific meetings, to medical journals, and to government agencies. Your name will remain secret and will not be mentioned in these reports.
Sometimes the group sponsoring your trial will be responsible for the cost of the medicine as well as the costs of medical tests that are required while you are in the trial. (Clinical trials usually require you to have more medical tests than you would have if you were not in the trial.) But in other trials, the cost of the medicine and only some of the medical tests will be covered. Some studies will reimburse you for the cost of traveling to and from your medical visits.
The U.S. National Institutes of Health, through its National Library of Medicine, has developed ClinicalTrials.gov to provide information about clinical research studies to patients, family members, and members of the public. You can contact this service online at www.ClinicalTrials.gov. Or you can get information over the phone by calling 1-888-346-3656 or (301) 594-5983.
For cancer-related clinical trials, go to www.cancer.gov or call 1-800-4-CANCER (1-800-422-6237). Trained staff who speak English and Spanish can answer questions and help you search for clinical trials for your type of cancer.
There may or may not be a clinical trial available in your area that relates to your particular disease or stage of disease.
Current as of:
March 9, 2022
Author: Healthwise StaffMedical Review: E. Gregory Thompson MD - Internal MedicineKathleen Romito MD - Family MedicineMichael Seth Rabin MD - Medical Oncology
Current as of: March 9, 2022
Author: Healthwise Staff
Medical Review:E. Gregory Thompson MD - Internal Medicine & Kathleen Romito MD - Family Medicine & Michael Seth Rabin MD - Medical Oncology
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