Poster Session II - A277 COMPARISON OF PATIENT RESPONSE TO FIRST VERSUS SECOND-LINE INFLIXIMAB IN MODERATE-TO-SEVERE ULCERATIVE COLITIS: A RETROSPECTIVE STUDY

Abstract Background Infliximab has remained a cornerstone in the management of moderate and/or severe ulcerative colitis (UC), however its outcomes after other advanced therapy failure has not been evaluated comprehensively Aims This study evaluates infliximab’s second-line effectiveness, identifies predictors of response, and compares outcomes to its first-line use. Methods A retrospective cohort study of adults with moderate or severe UC and treated with infliximab was identified at a tertiary care center between 2016-2024. Those patients were then categorized by line of therapy. Multivariable logistic regression was used to assess predictors of one-year clinical remission Results Among the 225 patients who met the study criteria, 143 (63.6%) received infliximab as first-line and 82 (36.4%) as second-line or subsequent therapy (Table 1). Clinical response at one year was significantly lower in second-line users (odds ratio 0.53, 95%CI 0.28–0.99, p = 0.049), and remained significantly lower after adjustment for biosimilar and concurrent steroid use. Other outcomes including one-year clinical remission, endoscopic improvement or remission were not significant (OR 0.69 (95% CI 0.44-1.08), p = 0.102; OR 0.84 (95% CI 0.50-1.43), p = 0.522; OR 0.79 (95% CI 0.46-1.34), p = 0.378; respectively). There was significantly more dose escalation of infliximab within one year (p = 0.049) among patients who had prior advanced therapy, as well as more discontinuation of infliximab within one year (p = 0.045), compared with first-line infliximab treated patients (Figure 1). Conclusions Infliximab continues to demonstrate high rate of clinical and endoscopic response, however its clinical response is significantly lower than in patients who received infliximab first-line. These findings support its continued use while highlighting the need for optimized patient selection and treatment strategies in therapy-exposed populations. A277 Table 1: Baseline characteristics Funding Agencies None