P0335Early changes in MAGNIFI and fistula volumetry are biomarkers that predicts clinical outcomes in perianal fistulizing Crohn’s disease. A multicentric study

Abstract Background Perianal fistulizing disease (PFD) in Crohn’s disease is associated with a slow and unpredictable healing course. MRI offers an objective tool to assess disease activity, and early identification of imaging biomarkers may help predict treatment response following novel cell-based therapies. We aimed to evaluate early MRI-derived biomarkers that predict clinical and radiological healing outcomes in CD patients with PFD treated with allogeneic adipose-derived stem cells (Darvadstrocel) in a multicentre cohort. Methods This multicentre, retrospective study was conducted across three Spanish tertiary IBD referral centres. Adult patients (≥18 years) with an established diagnosis of CD and MRI-confirmed perianal complex fistulizing disease (PFD) treated with darvadstrocel between 2018 and 2023 were included. Eligible patients had a pre-treatment pelvic MRI performed within 6 months before treatment and a follow-up MRI at 6 months. The primary endpoint was the proportion of patients achieving fistula healing at week 52, defined as absence of fistula drainage. Disease severity was assessed radiologically using the MAGNIFI score, and volumetric measurements of the active fistula component were calculated. MRI features before treatment and at 6-month MRI and their changes over time were analysed for their predictive value of clinical remission at week 52. Results A total of 43 patients (43% female; 13.6% with collections; median PDAI 5 IQR 3-6) were included, of whom 24 (55.8%) achieved clinical remission at week 52. MRI features differed significantly between patients with and without remission (Table 1). Logistic regression identified reduction in the volumetric active component of the fistula (OR 1.05 1.02–1.09, p = 0.11) and decrease in the MAGNIFI score (OR 1.04 1.01–1.10, p = 0.008) as independent predictors of clinical remission (Table 2). The overall model demonstrated a sensitivity of 0.88 and specificity of 0.84 for predicting clinical remission, with an area under the ROC curve of 0.91 (95% CI 0.80–1.00). Conclusion Early MRI changes, combining reduction in the MAGNIFI score and the active fistula volume, are associated with subsequent clinical remission in patients with PFD treated with darvadstrocel. Prospective validation in larger cohorts and using therapies with different mechanism of action is warranted. References: 1. Defining Radiological Healing in Perianal Fistulizing Crohn’s Disease: a TOpClass Global Expert Delphi Consensus. Anand E et al. Clin Gastroenterol Hepatol. 2025 Apr 8:S1542-3565(25)00248-4 2. Development and Validation of a Magnetic Resonance Index for Assessing Fistulas in Patients With Crohn’s Disease. Hindryckx P et al. Gastroenterology. 2019 Nov;157(5):1233-1244 3. Volumetric Changes in Perianal Fistulizing Crohn’s Disease Measured by Magnetic Resonance Is Feasible and Could Be a Potential Biomarker to Predict Clinical Outcomes.Caballol B. et al. United European Gastroenterol J. 2025 Sep;13(7):1217-1225 Conflict of interest: Dr. Rimola, Jordi: Grant: AbbVie, Takeda Advisory or consultancy: Janssen, Gilead, Alimentiv, Origo, Boehringer Ingelheim, Ferring, Clario, Avobis Bio Fees: Takeda, Alimentiv Tavares Nogueira, Sara Andreia: No conflict of interest Caballol Oliva, Berta: No conflict of interest Comas-Cufí, Marc: No conflict of interest Rodríguez-Lago, Iago: No conflict of interest aduna, Marta: No conflict of interest Elorza, Ainara: No conflict of interest Saidman, Julia: No conflict of interest Soriano, Elisa: No conflict of interest Ojeda, Marisa: No conflict of interest Anguiano, Gregorio: No conflict of interest Menys, Alex: CEO Motilent Associate Prof UCL Masamunt, Maria Carme: No conflict of interest Ricart Gomez, Elena: No conflict of interest Ordás Jiménez, Ingrid: I have received financial support for travel and educational activities, and have served as a speaker or advisory board member for the following companies AbbVie, MSD, Pfizer, Takeda, Janssen, Kern Pharma, Chiesi, Falk Pharma, and Faes Farma. I have also received research funding from AbbVie, Faes Farma, and Takeda. Table 1. Table 2.