What does “Phase I, Phase II, Phase III, and Phase IV” study mean?
Phase I is the first of four phases of clinical trails designed to establish the effects of a new drug in humans. Phase I studies are conducted on small populations of healthy humans to specifically determine a drug’s toxicity, absorption, distribution and metabolism. Phase II is the second of four phases of clinical trials that takes place only after the successful completion of phase I trials. In this phase, a drug is tested for safety and effectiveness in a slightly larger population of individuals who have been diagnosed with the disease or condition for which the drug was developed. Phase III is the third and last “pre-drug approval” round of testing of a drug that is conducted on large populations of afflicted patients. Phase III studies usually test the new drug in comparison with the standard therapy currently being used for the disease in question. The results in these trials usually provide the information that is included in the package insert and labeling. Phase IV clinical
