P1059Microstrctural variability in histological activity: a retrospective endocytoscopy pilot study of vedolizumab vs mesalazine in Ulcerative Colitis

Background The histological level evaluation is the key to target of treatment with Ulcerative Colitis (UC). In this study, We divided the patients into Vedolizumab (VDZ) and mesalazine groups and compared the improvement rate of microstrctural Variability by endocytoscopy (EC) in UC, and further to analyse the differences in the ability to improve histological activity between the two drugs. Methods In this study, we retrospectively analysed the case data of 46 patients diagnosed with UC at the Sixth Hospital of Sun Yat-sen University between January 2022 and January 2024 and divided them into the mesalazine group (n = 25) and the VDZ group (n = 21), and assessed the discrepancy EC improvement rate between the two groups after 12 weeks. Results In the ascending colon with the mesalazine group vs VDZ group, the 12-week overall EC improvement rate was 12%(n = 3) vs 33%(n = 7)(P < 0.05). In the rectum, the 12-week overall EC improvement rate was 48%(n = 12) vs 24%(n = 5) (P < 0.05). As a whole, the 12-week MES improvement rate was 52%(n = 13) vs 62%(n = 13) (P > 0.05); the 12-week overall EC improvement rate was 48%(n = 12) vs 57%(n = 12) (P > 0.05).There was no statistically significant difference in the ascending colon between the two drug groups. Conclusion VDZ demonstrates superior efficacy to mesalazine in the proximal colon. However, when the rectum is involved, the combination use of topical suppositories may achieve better therapeutic outcomes. References: [1] Rubin DT, Ananthakrishnan AN, Siegel CA, et al. ACG Clinical Guideline: Ulcerative Colitis in Adults. Am J Gastroenterol. 2019 Mar;114(3):384-413. [2] BryantRV, WinerS, TravisSP, et al. Systematic review：histological remission in inflammatory bowel disease. Is ‘complete’ remission the new treatment paradigm? An IOIBD initiative[J]. J Crohns Colitis, 2014,8(12)：1582-1597. [3] Ungaro R, Colombel J F, Lissoos T, et al. A Treat-to-Target Update in Ulcerative Colitis: A Systematic Review [J]. Am J Gastroenterol, 2019, 114(6): 874-883. [4] Magro F, Doherty G, Peyrin-Biroulet L, et al. ECCO Position Paper: Harmonization of the Approach to Ulcerative Colitis Histopathology. J Crohns Colitis. 2020, 7;14(11):1503-1511. [5] Nardone OM, Cannatelli R, Zardo D, Ghosh S, Iacucci M. Can advanced endoscopic techniques for assessment of mucosal inflammation and healing approximate histology in inflammatory bowel disease? Therap Adv Gastroenterol. 2019, 18;12:1756284819863015. [6] Neumann H, Vieth M, Neurath M F, et al. Endocytoscopy allows accurate in vivo differentiation of mucosal inflammatory cells in IBD: a pilot study [J]. Inflammatory bowel diseases, 2013, 19(2): 356-62. 7] Maeda Y, Ohtsuka K, Kudo S E, et al. Endocytoscopic narrow-band imaging efficiency for evaluation of inflammatory activity in ulcerative colitis [J]. World journal of gastroenterology, 2015, 21(7): 2108-2115. [8] Ueda N, Isomoto H, Ikebuchi Y, et al. Endocytoscopic classification can be predictive for relapse in ulcerative colitis [J]. Medicine, 2018, 97(10): e0107. [9] Rubin, David T. MD, FACG1; Ananthakrishnan, Ashwin N. MBBS, MPH, FACG2; Siegel, Corey A. MD, MS3; Barnes, Edward L. MD, MPH, FACG4; Long, Millie D. MD, MPH, FACG4. ACG Clinical Guideline Update: Ulcerative Colitis in Adults[J]. The American Journal of Gastroenterology 2025, 120(6):p 1187-1224. [10] Nakazato Y, Naganuma M, Sugimoto S, et al. Endocytoscopy can be used to assess histological healing in ulcerative colitis [J]. Endoscopy, 2017, 49(6): 560-563. [11] Iacucci M, Jeffery L, Acharjee A, et al. Ultra-high Magnification Endocytoscopy and Molecular Markers for Defining Endoscopic and Histologic Remission in Ulcerative Colitis-An Exploratory Study to Define Deep Remission [J]. Inflammatory bowel diseases, 2021, 27(11): 1719-1730. [12] Magro F, Doherty G, Peyrin-Biroulet L, et al. ECCO Position Paper: Harmonization of the Approach to Ulcerative Colitis Histopathology[J]. J Crohns Colitis. 2020, 14(11): 1503-1511. [13] Takishima K, Maeda Y, Ogata N, et al. Beyond complete endoscopic healing: Goblet appearance using an endocytoscope to predict future sustained clinical remission in ulcerative colitis[J]. Dig Endosc. 2022,34(5):1030-1039. [14] Chiu PW, Ng EK, To KF et al. Recognition of goblet cells upon endocytoscopy indicates the presence of gastric intestinal metaplasia. Dig Endosc 2014; 26:52–6. Conflict of interest: Mr. Guo, Qin: No conflict of interest Peng, Bo: No conflict of interest