Background: Professional associations publish guidance advising gastroenterologists on prescribing biosimilars; however, guidelines differ between countries and change over time. This study aimed to map the presence and content of guidance from European gastroenterology associations on TNFα inhibitor biosimilar use and its development over time. Research design and methods: Guidelines on biosimilar prescribing from national gastroenterology associations in the European Economic Area (EEA) partnered with the European Crohn’s and Colitis Organization (ECCO) were collected. Treatment guidelines and biosimilar position papers from 2010 to 2022 were included. Data were extracted using a template. Results: 26 of 30 EEA countries have an ECCO-partnered gastroenterology association, of which 14 (53.8%) had national guidelines addressing biosimilars, four (15.4%) followed ECCO’s position, and three (11.6%) had treatment guidelines without mentioning biosimilars. From five countries (19.2%) no guidelines were retrieved. Among 18 countries with guidance, 14 (77.8%) associations endorsed initiating biological treatment with biosimilars, and 13 (72.2%) endorsed transitioning from originator to biosimilar. Nine associations published multiple guidelines over time addressing biosimilars; overall, their positions became more encouraging. Conclusions: The majority of gastroenterology associations endorsed biosimilar use. The lack of (up-to-date) guidelines for some associations indicates an area of improvement to support biosimilar use in clinical practice
