Predictors of First Anti-TNF Treatment Failure in Patients with Inflammatory Bowel Disease: A Single-Center Cohort Study

Introduction: Despite proven efficacy of anti-TNF agents in inflammatory bowel disease, primary non-response affects up to one-third of patients, while secondary loss of response occurs at 13–21% per patient-year, often requiring dose optimization or switching to alternative advanced therapies. Methods: The present single-center cohort study at the University Hospital of Ioannina included biologic-naïve patients receiving anti-TNF therapy as their first biologic treatment. First anti-TNF treatment failure was defined as discontinuation due to persistent IBD activity despite maximal dose optimization (infliximab 10 mg/kg every 4 weeks, adalimumab 40 mg weekly). Patients with measurable anti-drug antibodies prior to anti-TNF dose intensification or discontinuation were excluded. Of 528 anti-TNF-treated patients, 286 (173 with CD, 113 with UC) met the inclusion criteria and were included in the final statistical analysis. Results: Anti-TNF failure occurred in 32.7% of Crohn’s (CD) and 32.9% of ulcerative colitis (UC) patients. Multivariable Cox regression identified complicated phenotype (stricturing or/and penetrating CD; HR = 1.9, p = 0.032) and concomitant corticosteroid use at anti-TNF initiation (HR = 2.03, p = 0.012) as independent predictors of anti-TNF failure in CD. Age at CD diagnosis showed a trend for statistical significance (HR = 1.02, p = 0.061), and after stratification, age at diagnosis ≥ 40 years conferred higher risk (HR = 1.93, p = 0.016), alongside persistent effects of complicated phenotype (HR = 1.83, p = 0.027) and corticosteroid use (HR = 2.01, p = 0.013). In UC patients, female sex predicted anti-TNF failure (HR = 2.13, p = 0.025). IBD-related bowel resection occurred in 26.6% of patients with CD and in 5.3% of patients with UC. Conclusions: Anti-TNF failure remains common despite optimization. Identifying immunogenicity-independent predictors may enable personalized treatment strategies and improve outcomes.