LAUSR

Abstract Objective Project NORTH compared real-world clinical and economic outcomes in Swedish patients with inflammatory bowel disease (IBD) who switched from originator infliximab to its biosimilar. Materials and methods Data from electronic medical records and Swedish national registries were linked. Switchers (patients switching from originator infliximab to its biosimilar between 1 April 2014, and 31 December 2017) and non-switchers (patients who received originator infliximab and did not switch to a biosimilar by 31 December 2017) were followed up until 31 October 2019. Results Baseline concomitant medication use, disease duration, and inflammatory markers were lower among switchers than non-switchers. At 6 months, the proportion of patients with stable disease was higher among switchers than non-switchers (71/109 [65%] vs 54/107 [50%]; p = .0385); differences were not significant in subsequent follow-ups. At 6 and 24 months, 98% and 93% of switchers, respectively, used concomitant medications versus 96% and 79% of non-switchers. Throughout the study, all-cause treatment discontinuation occurred in 74 (67%) switchers and 105 (95%) non-switchers. At 36-months, mean (SD) number of IBD-related in-patient care days was higher among non-switchers (2.95 [4.71]) than switchers (1.40 [4.20]), as were total medical costs (€16,740 vs €3,872). Conclusions No substantial differences in clinical outcomes or healthcare resource utilization were observed between switchers and non-switchers. Several analyses indicate that non-switchers might have more poorly controlled/severe disease than switchers at baseline. Overall, numerous difficulties might arise when executing a high-quality, real-world study, including possible selection bias for patients with better disease control for NMS, limiting the generalizability of the results.