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 2009-2022 and ≥1-year follow-up. Results 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 (IQR 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%; HR 1.5 [95% 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.