Monoclonal antibodies targeting tumor necrosis factor-alpha, integrin molecules, and interleukin-12/23 have become backbone therapies for Crohn's disease and ulcerative colitis. While clinically effective, these biologic therapies come with significant expense, contributing to overall healthcare spending in the USA. Biosimilars have the potential to significantly reduce expenditures secondary to the use of biologic medications such as infliximab and adalimumab, though their complicated manufacturing process results in inherent differences in structure when compared to the originator compounds. In this article, we review the available literature regarding biosimilars in IBD.
Several biosimilar agents to infliximab and adalimumab are currently FDA-approved, with many more currently in development. Initial clinical trials for approval have been conducted in one of the original indications for each originator biologic. There are growing data demonstrating similar clinical efficacy, immunogenicity, and safety of each of the approved infliximab and adalimumab biosimilars, both through indication extrapolation from other diseases such as rheumatoid arthritis and ankylosing spondylitis, as well observational data in patients with inflammatory bowel disease. Further research is ongoing regarding the efficacy and safety of substitution and interchangeability of biosimilars, as well as therapeutic drug monitoring for biosimilar agents. Research to date supports the utilization of reference biologics and biosimilars for new initiators, while additional data are being accrued regarding the interchangeability between these agents.