What are clinical trials?
Clinical trials are the means by which new drugs and treatments are tested to determine if they work. They are the engine that drives progress in medicine. For patients who have run out of other options, clinical trials offer a last chance at a potentially effective therapy. In some cases, they provide access to research treatments before they are made widely available.
But it's important to remember that clinical trials often involve unproven therapies. There is no guarantee that the treatments under investigation will work. And there is always a chance that they may cause serious side effects. Still, by participating in clinical trials, patients help advance the science of medicine.
Are there guidelines to participate in a clinical trial?
Yes. If you or someone you know is interested in participating in a clinical trial, there are some important things to remember.
Clinical trials have specific guidelines about participation. To make sure clinical trials are safe and provide reliable scientific information, researchers carefully choose who can -- and who can't -- take part. Clinical trials include "inclusion criteria" (the requirements for participating) and "exclusion criteria" (factors that disallow people from taking part). These are usually spelled out in descriptions of clinical trials made available to the public.
Participants must be informed and give their consent. Doctors and nurses are required to explain the details of the investigation to prospective participants. They also provide an "informed consent" document, with the details of the study explained in writing. Participants are asked to sign the document. Additional information is sometimes provided during the study, as it becomes available.
Participants are always free to withdraw from a study. Even after you sign an informed consent document and join a clinical trial, you can withdraw at any time. Withdrawing can jeopardize research, however. So it's important to learn everything you can before agreeing to join a trial.
Not everyone in a study always receives the active drug or treatment. Some studies test an active drug against a placebo. In blinded studies, neither participants nor researchers are allowed to know who is getting the real drug and who is being given the placebo. (A sealed code is used to keep track for later analysis.) Blinded studies are essential to eliminate bias in interpreting the results. Typically, if a drug appears to be working effectively, researchers will decide to "unblind" the study and offer the new treatment to everyone in the study.
How are clinical trials conducted?
Clinical studies are conducted in four phases. Phase I trials test a new drug or treatment in a small group of people to make sure its safe, to determine a safe dosage range, and to look at side effects. Phase II trials usually include more people and study both whether the drug is safe and whether its effective. Phase III trials include even more participants. They are designed to confirm a treatments effectiveness, monitor its side effects, and sometimes compare it to commonly used treatments. In Phase IV trials, drugs that have already been approved are studied for more information about their benefits, uses, or potential risks.
Investigational drugs are sometimes offered outside of clinical trials. The FDA allows manufacturers of investigational drugs to offer them to people who might benefit but who don't qualify for clinical trials. "Expanded access," as its called, is usually offered to people with a serious or life-threatening illness. The drug must already have been shown to be safe and effective in well-controlled studies.
For more information about clinical trials:
National Institutes of Health
This site provides detailed information about clinical trials and has a search feature that locates on-going clinical trials.
This site includes a listing of clinical trials organized by state.
National Institutes of Health, An Introduction to Clinical Trials: http://www.clinicaltrials.gov
Chronic Hepatitis C: Disease Management, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)