A clinical trial is a research study to answer specific questions about a new medical treatment (medicine/drug, medical device, new therapies, vaccines), or new ways of using known treatments. Clinical trials (also called medical research and research studies) are used to determine whether such new treatments are both safe and effective.
Carefully conducted clinical trials are the fastest and safest way to find treatments that work in people. A clinical trial is one of the final stages of a long and careful research process. Studies are done with patients to find out whether promising approaches to disease prevention, diagnosis, and treatment are safe and effective.
Most clinical research that involves the testing of a new drug progresses in an orderly series of steps, called phases. This allows researchers to ask and answer questions in a way that results in reliable information about the drug and protects the patients. Clinical trials are usually classified into one of three phases: