The European Medicines Agency's Committee for Advanced Therapies (CAT) provides a certification procedure for advanced therapy medicinal products (ATMPs) under development by micro-, small- and medium-sized enterprises (SMEs). The certification procedure involves the scientific evaluation of quality data and non-clinical data that SMEs have generated at any stage of the ATMP development process. It aims to identify any potential issues early on, so that these can be addressed prior to the submission of a marketing-authorisation application.