Real-world switching and discontinuation outcomes of infliximab biosimilars in patients with rheumatoid arthritis: A scoping review

BACKGROUND: Infliximab (IFX) was one of the first tumor necrosis factor inhibitors developed to treat rheumatoid arthritis (RA) and has transformed the treatment and management of many chronic inflammatory diseases. Large-scale studies in the real -world setting on the utilization patterns of IFX biosimilars are limited.OBJECTIVE: To conduct a scoping review of observational studies investigating the switching and discontinuation outcomes of the IFX biosimilars in patients with RA.METHODS: A comprehensive literature search was conducted in 3 databases (ie, PubMed, Embase, and Web of Science). This review identified observational studies that examined switching and/or discontinuation outcomes of IFX biosimilar products in adult patients with RA. Studies published in English between 2015 and 2020 were included. Studies that did not include either switching or discontinuation patterns of IFX biosimilars, had a pooled result for biologics, or were non -observational were excluded. Extracted data were summarized using descriptive statistics.RESULTS: The initial literature search yielded 1,130 studies. With 244 duplicate articles removed and 779 excluded after title and abstract screening, the search resulted in 107 studies for full-text screening. 18 articles were included in this review. 13 countries were represented in the included studies, with most studies originating in a European country and only one article from the United States. Discontinuation rates of IFX biosimilars were reported by 14 studies and varied substantially from 8.3% to 87.0%. 4 studies (22%) directly compared discontinuation rates between IFX reference and biosimilar. Switching rates, similarly, had a great variance from 4% to 81.5%; only 4 articles described rates specifically in patients with RA. The most common causes of discontinuation were ineffectiveness and adverse effects. CONCLUSIONS: The growing market of bio-logic products necessitates more large-scale studies examining the real-world treatment patterns of these therapy options to pro-vide reassurance to and build trust among patients and clinicians. Our findings suggest the inconclusiveness of current literature on the real-world implications of IFX biosimilars discontinuation and product switching. This review captures the heterogeneity in reported data and identifies areas for future research to provide clarity to the value of IFX biosimilars.