Phase IV trial
phase IV trial
After a drug has been approved for use in humans, a pharmaceutical company may continue testing in phase IV, even though the drug is already on the market. Phase iV testing may be required to answer ongoing FDA concerns, or the company may use phase IV to test the compound for other patient groups or indications. Phase IV data is often used to suggest modifications to a drug's labeling information, and studies may even be designed to gather information for marketing purposes.