P089 REAL-WORLD EXPERIENCE: CLINICAL AND ENDOSCOPIC EFFECTIVENESS OF STANDARD VEDOLIZUMAB DOSING AND MODIFIED MAINTENANCE DOSING IN PATIENTS WITH MODERATE-SEVERE CROHN’S DISEASE

Background Vedolizumab (VDZ) is an effective treatment for Crohn’s disease (CD); however, inadequate and loss of response is common. Pivotal VDZ trials evaluated alternative dosing intervals, demonstrating numeric but not statistical superiority in efficacy as compared to FDA-approved dosing. The safety and effectiveness of FDA-approved and modified-dosing schedules in a real-world population are unknown. We aimed to evaluate clinical and endoscopic effectiveness & safety of standard and modified maintenance VDZ dosing in a real world cohort. Methods We retrospectively reviewed CD patients (pts) treated with >3 months VDZ, assessing Harvey Bradshaw Index (HBI), Simple Endoscopic Score for Crohn’s disease (SESCD), Short Inflammatory Bowel Disease Questionnaire (SIBDQ), C-reactive protein (CRP), albumin and hematocrit prior to and following standard VDZ dosing, and prior to and following modified VDZ maintenance dosing. We measured duration on therapy and adverse events. Results We identified 226 eligible pts, mean age 41.5 years, 55.3% female, median disease duration 10 years, 88.9% with prior biologic exposure. Mean duration on VDZ was 28.3 months. Standard VDZ dosing: 61.5% of pts with active clinical disease and adequate follow up data achieved clinical response after 3–12 months; 41.0% had clinical remission. 51.9% of pts with active endoscopic disease and adequate follow up data achieved mucosal improvement; 42.3% had endoscopic remission; 26.0% had mucosal healing after 3–24 months. 50.0% of pts with elevated CRP and adequate follow up data normalized CRP after 3–12 months. Modified maintenance dosing: 72 non-remitters to standard VDZ dosing received modified VDZ maintenance dosing. 51.5% of pts with active clinical disease prior to starting dose modification and adequate follow up data achieved clinical response after 3–12 months of modified maintenance dosing; 42.4% had clinical remission. 22.2% of pts with SESCD ≥3 prior to starting dose modification achieved mucosal improvement after 3–24 months; 22.2% had mucosal healing. 26.7% of pts with SESCD ≥4 prior to starting modified dosing had endoscopic remission after 3–24 months. 50.0% of pts with elevated CRP and adequate follow up data normalized their CRP after 3–12 months. Safety: 82.7% of pts reported ≥1 adverse events, most commonly infection and worsening CD symptoms. Discussion Standard VDZ dosing resulted in clinical and endoscopic improvement in pts with moderate-severe CD, with prior exposure to multiple advanced therapies. For non-remitters to standard dosing, modified VDZ maintenance dosing improved clinical disease activity in ∼50% of pts and improved endoscopic disease activity in ∼20% of pts, suggesting that for pts who did not achieve remission with standard VDZ dosing, modified VDZ dosing may result in clinical and endoscopic improvement.