COMPARATIVE REAL WORLD OUTCOMES OF INTRAVENOUS VERSUS SUBCUTANEOUS VEDOLIZUMAB IN ULCERATIVE COLITIS AND CROHN’S DISEASE

Abstract INTRODUCTION Vedolizumab, a gut-selective α4β7 integrin antagonist, is approved in two formulations: 300 mg intravenous (IV) infusion and 108 mg subcutaneous (SC) injection. While both target the same pathway, real-world data directly comparing these routes remain limited. This study evaluated clinical outcomes between IV and SC vedolizumab in ulcerative colitis (UC) and Crohn’s disease (CD). METHODS We conducted a retrospective analysis using the TriNetX US Collaborative Network. Adult UC and CD patients were stratified by vedolizumab administration route (300 mg IV vs. 108 mg SC). Propensity score matching balanced age, race, gender, and comorbidities (e.g., hypertension, diabetes). Outcomes included hospitalization, corticosteroid use, colectomy (UC), and surgery (CD). Odds ratios (OR) with p-values were calculated. RESULTS In UC, the incidence of C. difficile was higher in the IV group (18 vs. 10; OR 1.821). Mortality (10 each; OR 1), sepsis (12 vs. 13; OR 0.922), shock (10 each; OR 1), abscess (10 each; OR 1), and colectomy (10 each; OR 1) showed no difference. Fistula was slightly less frequent with IV (13 vs. 18; OR 0.717). Notably, hospitalizations were significantly higher with IV (83 vs. 44; OR 2.003, p < 0.0001). Steroid use was also greater with IV (303 vs. 225; OR 1.347, p < 0.0001). In CD, C. difficile, mortality, sepsis, and abscess were equal (10 each; OR 1). Fistula was similar (13 vs. 14; OR 0.926, p = 0.844). No colectomies occurred. A significant difference was observed in shock, with 10 cases in the IV group versus none with SC (p = 0.001). Hospitalizations were higher in IV (37 vs. 10; OR 4.041, p < 0.0001). Steroid use was more frequent with IV (118 vs. 98; OR 1.318), though not statistically significant (p = 0.097). CONCLUSION Vedolizumab 300 mg IV and 108 mg SC demonstrated largely similar safety and effectiveness profiles in UC and CD. However, IV administration was associated with higher rates of hospitalization and steroid use, particularly in UC, and with shock in CD. These findings highlight potential differences by formulation that may inform individualized treatment strategies in inflammatory bowel disease.