About
Clinical trials are highly controlled studies used to determine the effectiveness and safety of a new drug treatment or other intervention in people. Clinical trials are conducted in phases with each phase designed to answer different questions about a potential therapy.
Phase I trials test an experimental drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase II trials test the experimental drug or treatment in a larger group of people (100-300) to determine if it is effective and to further evaluate its safety.
Phase III trials test the experimental study drug or treatment in a large group of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the experimental drug or treatment to be used safely.
Phase IV trials use post marketing studies to collect additional information about the drug or treatment after it has been approved including its risks, benefits, and optimal use.
Most clinical trials examine the effectiveness of a drug or treatment by comparing its effects to those of another drug or treatment, or to a “dummy” treatment known as a placebo. A placebo is a pill or procedure that is designed to have no effect on the disease or condition under study. The people taking the placebo provide a comparison group to ensure that any effects seen in the group exposed to the experimental drug or treatment are caused by that treatment and not just by chance. Most clinical trials are double blind studies, meaning that neither the experimenters nor the participants know which participants are receiving the experimental treatment and which are receiving a placebo until after the trial is completed.