Real-life durability and risk factors for biologic discontinuation in pediatric inflammatory bowel disease: results from the SIGENP IBD registry

Background and aims: This study aims to evaluate the real-life durability of biologic therapies and to identify factors associated with biologic persistence in pediatric inflammatory bowel disease (IBD). Methods: We analyzed data from the IBD-registry of the Italian Society of Pediatric Gastroenterology, Hepatology, and Nutrition (SIGENP) of patients initiating biologics between 2009 and 2022 and >= 1-year follow-up. Results: A total of 1184 patients (747 with Crohn's disease [CD], 437 with ulcerative colitis or IBD unclassified [UC/IBD-U]) were included, accounting for 1709 treatment courses. The median follow-up was 43 months (interquartile range 28-64). Overall, 33% received a second-line biologic, 9% third-line, and 2% fourth-line. First-line biologic durability was significantly lower in UC/IBD-U vs CD, with inferior persistence at 1, 2, and 3 years (61%, 51%, and 44% vs 88%, 75%, and 67%; hazard ratios [HR]: 1.5, 95% confidence interval [CI] 1.2-1.9, P = .002). In CD, infliximab had inferior durability then adalimumab (72%, 59%, and 50% vs 91%, 82%, and 77%; HR 2.0, 95% CI, 1.5-2.7, P < .0001). In both CD and UC/IBD-U, age <6 years was a risk factor for treatment discontinuation (HR 1.8, 95% CI, 1.2-2.7, P < .01) while therapeutic drug monitoring (TDM) emerged as protective (HR 0.5, 95% CI, 0.4-0.7, P < .0001). Combination with an immunomodulator had no significant impact on durability (HR 0.9, 95% CI, 0.8-1.2, P = .54). Conclusions: Biologic persistence varied by disease type and biologic agent. TDM was associated with longer treatment durability, while combination therapy had a limited effect. Further prospective studies are needed to refine biologics optimization strategies in pediatric IBD.