Comparing Long-Term Infliximab Persistence Following a Switch to a Biosimilar in Patients With Inflammatory Bowel Disease: No Cause for Concern.

Introduction: Several studies have demonstrated that switching stable patients with inflammatory bowel disease (IBD) from originator to biosimilar infliximab is noninferior to continuing originator infliximab. However, "real-world" data comparing long-term outcomes between switch and nonswitch cohorts is lacking. This study aimed to address this gap by comparing long-term outcomes in IBD patients across switch and nonswitch cohorts.

Methods: The SAME study was a multicenter, prospective parallel cohort noninferiority study, that enrolled Australian IBD patients in steroid-free clinical remission on maintenance originator infliximab, who either continued originator infliximab (n = 141) or switched to biosimilar (CT-P13) infliximab (n = 204). Here, we present long-term outcomes, with treatment persistence beyond 48 weeks as the primary outcome. Disease worsening, defined as any of infliximab discontinuation, dose escalation, antibody development, or adverse event, were secondary outcomes of interest.

Results: Of 345 patients enrolled in the SAME study, 320 (92.7%) patients were followed up beyond 48 weeks (median: 54.2 months [IQR 46.1-59.3]). There were no differences in infliximab discontinuation between switch and nonswitch cohorts (35.3% vs. 37.6%, p = 0.47). Infliximab discontinuation due to disease worsening (21.7% vs. 23.6%), dose escalation (35.2% vs. 32.4%), antibody development (5.3% vs. 11.3%), and infliximab-related adverse events (7.8% vs. 8.3%), were also comparable (all p > 0.70) between switch and nonswitch cohorts.

Conclusions: Long-term infliximab persistence was similar between switch and nonswitch cohorts over 4 years of follow-up. These data represent the longest duration of "real-world" follow-up, and should provide further reassurance that nonmedical switching is safe and clinically comparable to ongoing originator infliximab in clinically stable patients with IBD.