A type of clinical trial that studies the side effects caused over time by a new treatment after it has been approved and is on the market. These trials look for side effects that were not seen in previous trials and may also study how well a new treatment works over a long period of time. Phase IV trials are also known as post-marketing surveillance trials. Phase IV trials include safety monitoring (pharmacovigilance) and ongoing technical support of a drug after it receives permission for sale.
Phase IV studies may be required by regulatory authorities or may be conducted by the sponsoring company for competitive reasons (finding a new market for the drug) or for other reasons (for example, safety surveillance is designed to detect any rare or long-term adverse effects in a much larger patient population over a longer period of time than was possible during phase I—III clinical trials. Harmful effects discovered in phase IV trials may cause a drug to be withdrawn from the market or restricted to certain uses. At this stage, other drug indications could be determined. As the last phase of clinical research, phase IV trials involve many participants and a lot of time.
These are sometimes referred to as post-market surveillance. What is a phase IV clinical trial? Some trials have an earlier stage called phase 0, and there are some phase 4 trials that are performed after a drug has been authorized. Each stage of a clinical trial has its own purpose of ensuring that a treatment is safe and effective for public use.
