P661 Post-operative prophylaxis with anti-TNF in patients with Crohn’s disease who are anti-TNF experienced is associated with higher rates of prophylaxis failure

Abstract Background Anti-TNF therapy is the most effective strategy for post-operative prophylaxis in patients with Crohn’s disease (CD) who are considered to be at high risk for recurrence. However, some patients fail to maintain long-term remission under these therapies. We aimed to assess predictors for the efficacy of post-operative anti-TNF therapy. Methods Patients with CD who underwent a curative bowel resection and were given post-operative anti-TNF prophylaxis between 2010 and 2019 were identified, and their data analysed retrospectively. Patients were assessed for disease recurrence at their first post-operative colonoscopy, a Rutgeerts score of >2a or clinically active disease that required a change in treatment was considered prophylaxis failure. Results Overall, 51 patients were included in our analysis. Male: 23 (45%); most of them had a penetrating complication (n = 23, 63%) that required surgery. Median age at surgery: 32 years (IQR 26–46). Anti-TNF therapy was started within a median of 9 weeks (IQR 6–14) post-surgery. Anti-TNF naïve: 14/51; 37/51 were anti-TNF experienced; of whom, 23 (62%) were treated with the same anti-TNF given before surgery. Disease recurrence occurred in 23 patients (45%) within a median follow-up of 13 months (IQR 8–26). Of the patients with disease recurrence, 10 (43%) were male, the median age of CD diagnosis was 26 years (IQR 15–49), 15 (65%) had penetrating disease, 5 (21%) had previous surgery, and 5 (21%) were active smokers. Disease recurrence was more common among patients operated at an older age (43 vs 33 years, p < 0.05) and in patients who had previous exposure to anti-TNF agents (56% vs. 14%, p = 0.01). In a multivariate Cox regression analysis, previous anti-TNF exposure was predictive of disease recurrence after surgery (HR 5.5, 95% CI 1.3–24, p < 0.05). Conclusion Post-operative prophylaxis using anti-TNF therapy in patients with CD who are anti-TNF experienced is associated with high rates of disease recurrence. This failure might be attributed to immunogenicity or pharmacodynamic failure. Closer monitoring and early treatment modifications should be considered in anti-TNF experienced patients.