that has been tested in the laboratory and has been
approved by the U.S. Food and Drug Administration (FDA) for
testing in people. Clinical trials test how well
investigational agents work and whether they are
safe to use. An investigational agent may be
approved by the FDA for use in one disease or condition but
still be considered investigational in other diseases or
conditions. Also called experimental drug, IND, investigational drug, and investigational new drug.