Efficacy and safety of CT-P13 in inflammatory bowel disease after switching from originator infliximab: Exploratory analyses from the NOR-SWITCH main and extension trials

Background: The NOR-SWITCH main and extension trials demonstrated that switching from originator to biosimilar infliximab (CT-P13) is efficacious and safe across six diseases. However, a subgroup analysis of Crohn's disease (CD) in the main trial displayed a close to significant difference favouring originator infliximab, and more scientific data have therefore been requested. Objective: The aim was to assess treatment efficacy, safety, and immunogenicity in an explorative subgroup analysis in CD and ulcerative colitis (UC) in the NOR-SWITCH trials. Patients and methods: The 52-week, randomised, non-inferiority, double-blind, multicentre, phase 4 NOR-SWITCH study was followed by a 26-week open extension trial where all patients received treatment with CT-P13. Treatment efficacy, safety, and immunogenicity in CD and UC were assessed throughout the 78-week study period. Results: The main and extension trials included 155 and 93 patients with CD and 93 and 80 patients with UC, respectively. Demographic and baseline characteristics were comparable in both treatment arms within patient groups. There were no differences in the main and extension trials regarding changes in activity indices, C-reactive protein, faecal calprotectin, patient's and physician's global assessment of disease activity and patient-reported outcome measures in CD and UC. Moreover, comparable results were also demonstrated for trough serum levels, presence of anti-drug antibodies, and reported adverse events. Conclusion: Efficacy, safety, and immunogenicity of both the originator and biosimilar infliximab were comparable in CD and UC in the NOR-SWITCH main and extension trials. These explorative subgroup analyses confirm that there are no significant concerns related to switching from originator infliximab to CT-P13 in CD and UC.