The term "ATMs" is understood to refer to both advanced therapy medicinal products that have been granted a marketing authorization and advanced therapy medicinal products that are the subject of clinical trials or are used as a reference in a clinical trial (investigational advanced therapy medicinal product). This guide specifies the GMP requirements that must govern the manufacture of ATMPs that have been granted a marketing authorization and ATMPs used in a clinical trial context. This guide does not apply to medicinal products other than ATMPs. However, the detailed guidelines referred to in the second paragraph of Article 47 of Directive 2001/83/c4 and Article 63(1) of Regulation (EU) No 536/2014 do not apply to ATMPs unless specifically referred to in these guidelines. If specific provisions only concern advanced therapy medicinal products that have been granted a marketing authorization, the term used is "authorized ATMPs".