Biosimilar and Follow-on Insulin: The Ins, Outs, and Interchangeability

Objective: To provide an overview of the differences between biosimilars and generics, and to summarize regulatory requirements and outstanding issues related to biosimilar insulins in the United States, including the issue of interchangeability. Data Sources: References were obtained using MEDLINE searches, the bibliographies of articles identified during the searches, review articles, and general Internet searches. Key words included the following: diabetes, insulin, biosimilar, regulatory, follow-on, and interchangeability. Study Selection and Data Extraction: Articles, studies, regulatory documents, and opinion pieces that addressed issues around biosimilar/follow-on insulins and interchangeability of insulins in people with diabetes were selected for inclusion in this narrative review. Data Synthesis: There is understandable interest in the potential for new copies of existing insulins-termed biosimilar insulins or follow-on insulins-to reduce the substantial and growing costs associated with managing the diabetes epidemic and to improve access, as has been achieved with conventional generic drugs. However, biosimilars or follow-on insulins are not generics. There are critical differences between biologic products and conventional chemical drugs, which present specific challenges to manufacturers, regulators, and clinicians. Conclusions: Health care providers and payers need to be aware of the issues surrounding biosimilar and follow-on insulins as they become more widely available in the coming years. In particular, in the face of limited data on comparative safety and efficacy, careful consideration needs to be given when interchanging between originator and biosimilar drugs, when switching patients from one biosimilar drug to the other.