Abstract
These days, the use of biosimilars for the treatment of bio-naive patients is well established. However, the transition of patients being treated with a bio-originator to its biosimilar is still a topic of discussion. The main issue is which approach to use when initiating the non-medical transition. The first real-world examples contain both mandatory and non-mandatory approaches, resulting in a variety of acceptance and discontinuation rates. At this moment a non-mandatory approach, based on shared decision making, is preferred by international guidelines and the Task Force on the Use of Biosimilars to Treat Rheumatological Diseases. However, clear definitions of mandatory and non-mandatory are lacking, as a result of which these terms may be wrongly used in some studies. This article aims to provide an overview of transition approaches used in the Netherlands, and how the approach used relates to acceptance and discontinuation rates of the biosimilar.