A clinical trial is an experiment: it may test the safety and usefulness of a new therapy, or it may test several different kinds of treatment to see which one is better. Some clinical trials test treatments for HIV, and others study drugs to treat or prevent the opportunistic diseases and cancers that commonly affect people with AIDS. Finally, studies may test easier ways to take medications, or ways to treat side effects of medications.
Some trials, known as phase I studies are mainly tests of safety (although they may collect some minimal information on the treatment's usefulness). Other studies, known as phase II and phase III studies, collect lots of information about both safety and usefulness. Finally, phase IV studies may test several different approved treatments to find out if one is better than others.
Although participating in a study may be a useful part of your treatment, it is important to know that the main purpose of the trial is to test the treatment – not to provide the best possible medical care. Therefore, study participation is not a good substitute for regular doctor visits.
Most, though not all clinical trials compare at least two different treatments. For example, a study might compare a new anti-HIV therapy in combination with older drugs to a combination of just older drugs. When a new treatment is compared to more standard treatments, the second group is known as the "control" group. Sometimes new medicines are compared to a placebo. A placebo is a fake pill that contains no medicine, but that looks exactly like the tested treatment. When studies compare several different medicines, you may not be told which treatment you are receiving.
The government usually tries to carefully regulate clinical trials. The information on this page is specific to the United States, however, most developed countries offer similar regulations for clinical trials.
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