In August 2022, the final version of the new Annex 1 of the GMP, which details the requirements for the manufacture of sterile medicinal products, was published. The new Annex 1 will enter into force on 25 August 2023 and there are many doubts about what will happen with advanced therapy medicinal products, as these are considered sterile medicinal products by definition and in most cases without terminal sterilisation. The new Annex 1 as it stands is more restrictive than Part IV of the GMP specific to advanced therapy medicinal products. Therefore: To what extent does the new Annex 1 apply? What happens with already authorised open facilities? What happens with new facilities to be built? Is it necessary to implement closed production systems?