This article discusses how different regulatory requirements for a dossier requesting marketing authorisation for a medical drug affect the deliverables from development functions and the submission groups including medical writing. The content of the dossier submitted is strongly interlinked to the legal basis selected for a regulatory filing. This drives the requirements of data from different areas of development as well as of dossiers that can be summarised mainly into the general categories of Chemistry, Manufacturing and Controls (Common Technical Document (CTD) dossier Module 3), non-clinical (CTD dossier Module 4), and clinical (CTD dossier Module 5) reports. This article addresses different types of regulatory pathways in the EU and the US with case examples where possible. The pathways used in the generic and biosimilar industries are discussed regarding expectations of authorities in an application type. Although this article focuses on clinical research and clinical data requirements within the generic and biosimilar industries, it also addresses how other parts of the dossiers are affected.