P0960Long-term outcomes of vedolizumab targeted therapy in patients with very early onset Inflammatory Bowel Disease

Background Vedolizumab (VEDO) is approved for adults with moderate to severe inflammatory bowel disease (IBD), but limited data exists in patients presenting ≤ 6 years, known as very early onset (VEO)-IBD. We aimed to describe clinical outcomes and adverse events in VEO-IBD children treated with VEDO. Methods We performed a single-center retrospective cohort study of patients with VEO-IBD, treated with VEDO between 2014-2025. Inclusion criteria were therapy duration ≥ 6 months and absence of known monogenic disease, and data were collected at baseline, 6 and 12 months. The primary outcome was therapy durability at 12 months. Secondary outcomes included Physician Global Assessment (PGA) quiescent and clinical remission (Pediatric Crohn’s Disease Activity Index (PCDAI) ≤ 10 or Pediatric Ulcerative Colitis Activity Index (PUCAI) < 10) at 12 months, mucosal healing, change in disease biomarkers and adverse events. Descriptive statistics were used to evaluate differences across time points. Results Of the 64 children with VEO-IBD treated with VEDO, 59 met the inclusion criteria (68% male, 47% CD, 51% IBD-U, 2% UC). The median age at presentation was 2.92 years (IQR 2.08-4.46) and the median age at VEDO initiation was 6.42 years (4.38-8.63). 64% of CD patients had ileocolonic disease and 81% of UC/IBD-U had pancolitis. 63% of patients were biologic-naive, and VEDO was used as dual therapy in 16 patients, including canakinumab (n = 3), tacrolimus (n = 2), ruxolitinib (n = 1), methotrexate (n = 4), adalimumab (n = 1), sirolimus (n = 3), ustekinumab (n = 1). The primary outcome of therapy durability at 12 months was achieved by 95% of patients. Three patients discontinued VEDO after 6 months due to worsening symptoms, transitioning to ustekinumab (n = 1) and infliximab (n = 2). The proportion of patients with quiescent disease by PGA increased from 30% (17/56) at baseline to 73% (41/56) at 12 months. Clinical remission was achieved by 74% (40/54) of patients at 12 months compared to 28% (15/54) at baseline. 45% (10/22) of patients achieved mucosal healing. Median PCDAI improved from 15 (8.13-23.75) at baseline to 5 (3.13-13.75) at 12 months, and PUCAI decreased from 15 (10-35) to 0 (0-7.5) at 12 months. Median calprotectin levels improved from 588 ug/g (297.50-985.25) to 135 ug/g (52-376.52). All 8 patients successfully discontinued systemic steroids by 12 months. 14 patients had ≥ 1 hospitalization while 5 patients underwent surgery due to IBD symptoms. No serious adverse events were observed. Conclusion In our experience, vedolizumab showed 12 months therapy durability in 95% of the patients with VEO-IBD in this cohort. Quiescent disease and clinical remission were achieved in > 70% of patients with few adverse events. Conflict of interest: Dr. Macchi, Marina: No conflict of interest Gaddipati, Shreya: No conflict of interest Baccarella, Alyssa: No conflict of interest Hartman, Catherine: No conflict of interest White, Laura K: No conflict of interest Patel, Trusha: No conflict of interest Boyer, Brooke: No conflict of interest Dawany, Noor: No conflict of interest Conrad, Maire A: No conflict of interest Kelsen, Judith R: No conflict of interest