The company marketing a product may set up post-authorisation clinical trials for purposes of obtaining information on use in particular patient populations (e.g. the elderly, or liver-impaired) or for obtaining other data on the way that the product is used.

Post-authorisation studies that are set up specifically to evaluate product safety are referred to in as “post-authorisation safety studies” or PASS. These studies are described in the risk management plan at the time of application for marketing authorisation and become post-marketing commitments for the company. They may also be required to be set up, if regulatory authorities consider that there is a need for additional safety information after marketing.