P0619 Loss of response to anti-tumor necrosis factor-alpha (Anti-TNFα) therapy in Inflammatory Bowel Disease: A Single-Center Experience

Abstract

Abstract Background Loss of response (LOR) to anti-tumour necrosis factor-alpha (anti-TNFα) therapy remains a major challenge in the long-term management of inflammatory bowel disease (IBD). However, data on its prevalence and predictive factors remain limited in our setting. The aim of this single-centre study was to assess the prevalence and predictors of loss of response to anti-TNFα therapy in patients with IBD. Methods This retrospective study included all IBD patients treated with infliximab or adalimumab in our gastroenterology department between 2018 and 2025. Loss of response was defined as the recurrence of symptoms after an initial clinical improvement. Logistic regression analysis was used to identify factors associated with LOR (p < 0.05). Results Seventy-nine patients (43 males, 36 females; mean age 42 years [14–72]) were included, comprising 62 with Crohn’s disease and 17 with ulcerative colitis. Primary non-response occurred in 7.6%. LOR was observed in 41.8% (33 patients), with a mean onset of 2.5 years [1–7] and 36% occurring within the first year. Low infliximab trough levels were significantly associated with LOR (p = 0.008; OR = 0.053, 95% CI [0.006–0.46]). The presence of anti-drug antibodies showed a non-significant association (p = 0.539; OR = 2.23, 95% CI [0.17–28.5]), while other studied variables, including sex, smoking status, family history, disease type, disease duration, and extra-intestinal manifestations, were not significantly associated with loss of response (all p > 0.05). Conclusion Loss of response occurred in nearly half of patients, consistent with previous reports. Low serum infliximab concentrations were the main predictive factor, highlighting the importance of therapeutic drug monitoring to optimise long-term outcomes. Conflict of interest: Ms. Bostani, Sonia: No conflict of interest Aws, El Haj Salah: No conflict of interest Mohamed, Ghanem: No conflict of interest Bizid, Sondes: No conflict of interest Bouali, Riadh: No conflict of interest Ben Abdallah, Hatem: No conflict of interest