P0909 Efficacy of biologic therapy according to Crohn’s Disease location: a real-life observational study
Authors: Ferretti F , Cannatelli R , Molteni C B , Carvalhas Gabrielli A M , Carmagnola S , Maconi G 
Published: January 2025

Abstract

Background
The location of Crohn’s disease (CD) can affect evolution, disease monitoring, and management of patients. In daily practice, clinicians perceive a lower efficacy of therapies in ileal-dominant CD compared to other CD locations, but recent evidence is controversial.
The primary aim of our study was to explore the efficacy of available biologic agents according to the main CD location in a real-life cohort of patients.

Methods
We retrospectively included all CD patients starting a biologic therapy at our IBD Centre from 2021 to 2023. In case of switch of therapy, the patient was reinserted and the endpoints re-evaluated. The efficacy was evaluated in terms of clinical remission (Harvey Bradshaw Index [HBI] &lt;5) and clinical response (≥3 point decrease of HBI), endoscopic remission (Simple Endoscopic Score [SES-CD] &lt;4), and response (≥2 point reduction of SES-CD), and ultrasound (US) response (resolution or improvement &gt;25% of bowel wall thickening).

Results
We enrolled 127 consecutive CD patients under biologic therapy (75 males, mean age 49±15 years); 40 patients were treated with multiple lines of biologic therapy leading to a total of 181 cases analysed: 35 on Infliximab (IFX), 76 on Adalimumab (ADA), 19 on Vedolizumab (VDZ), 47 on Ustekinumab (USK) and 3 in dual therapy (VDZ+USK). Of these, 70 cases (39%) had an ileal-dominant CD (L1), while 111 (61%) had a colonic or ileocolic involvement (L2, L3).
According to disease location, patients with an ileal-dominant CD showed a higher rate of clinical remission after the induction (59/68 [86.8%] ileal CD patients versus 77/106 [72.6%], p=0.028). Still, this difference was not maintained at W52 (53/62 [85.5%] versus 64/78 [82.1%], p=0.586). No difference was observed in clinical response.
The clinical efficacy of different biologic therapies is shown in Table 1. USK was more effective in ileal patients, both after induction and at W52 (p=0.060). Moreover, a significantly higher clinical response was observed at W52 in ileal patients treated with ADA. No difference was observed in terms of endoscopic or US efficacy by CD location.
During the observation period, ileal CD patients showed a higher rate of clinical flare-up (27/42 [38.6%] versus 21/105 [20.0%], p=0.007). However, the hospitalization and surgery rate was similar. Globally, the discontinuation rate was 71/181 (39%) after a mean time of 14 months, in 54 cases for inefficacy (18 in ileal CD versus 36, p=0.33).

Conclusion
The ileal-dominant location of CD does not seem to significantly affect the efficacy of biologic agents in a real-life cohort of CD patients. Among the available therapies, USK and ADA seem to show a slight clinical advantage in managing the ileal forms compared to other biologics.

References
1.Dulai PS, Singh S, Vande Casteele N, et al. Should We Divide Crohn’s Disease Into Ileum-Dominant and Isolated Colonic Diseases? Clin Gastroenterol Hepatol. 2019;17(13):2634-2643. doi: 10.1016/j.cgh.2019.04.0402.
2.Atreya R, Siegmund B. Location is important: differentiation between ileal and colonic Crohn’s disease. Nat Rev Gastroenterol Hepatol. 2021;18(8):544-558. doi: 10.1038/s41575-021-00424-6.
3.Gordon H, Minozzi S, Kopylov U, et al. ECCO Guidelines on Therapeutics in Crohn’s Disease: Medical Treatment. J Crohns Colitis. 2024;18(10):1531-1555. doi: 10.1093/ecco-jcc/jjae091.