ABSTRACT
BACKGROUND AND AIMS: Biosimilar infliximab CT-P13 offers the potential for large drug acquisition cost savings. However, there are limited published data regarding its efficacy, safety, and immunogenicity in inflammatory bowel disease [IBD], particularly in switching IBD patients from originator to biosimilar infliximab. We present the outcomes of a service evaluation of switching IBD patients established on originator infliximab to biosimilar, using a managed switching programme funded via a gain share agreement in a UK teaching hospital. METHODS: Evaluation outcomes included drug persistence, changes in drug acquisition costs, patient-reported side effects, adverse events, patient outcomes assessed using the IBD-control Patient-Reported Outcome Measures [PROM] questionnaire, serum drug and antibody levels, and routinely collected biochemical markers. RESULTS: A total of 143 patients with IBD [118 Crohn's disease, 23 ulcerative colitis, 2 IBD unclassified] were switched from originator infliximab to CT-P13. Patients reported a similar incidence of side effects before and after switch. No clinically significant differences were observed in mean C-reactive protein [CRP], albumin, haemoglobin levels, or platelet and white cell counts after the switch to CT-P13, whereas mean IBD-control-8 score improved from 10.4 to 11.2 [p = 0.041]. There was no significant difference in drug persistence between biosimilar and originator infliximab [p = 0.94] and no increase in immunogenicity was found. Drug acquisition costs decreased by £40,000-60,000 per month. CONCLUSIONS: A managed switching programme from originator infliximab to biosimilar CT-P13 in IBD, using a gain-share agreement, delivers significant cost savings and investment in clinical services while maintaining similar patient-reported outcomes, biochemical response, drug persistence, and adverse event profile.