P636 Real-world clinical effectiveness and safety of vedolizumab and ustekinumab in biologic-naïve patients with Crohn’s disease: Results from the EVOLVE Expansion study

Abstract Background This study evaluated real-world clinical effectiveness and safety of vedolizumab (VDZ), a gut-selective α4β7-integrin inhibitor ustekinumab (UST), an IL-12/23 p40 inhibitor, as first-line biologic treatment (Tx) for patients (pts) with Crohn’s disease (CD). Methods The EVOLVE Expansion (NCT05056441) was multicenter, observational, retrospective cohort in biologic-naïve pts CD (≥18 years old) who initiated VDZ or UST Tx Australia, Belgium Switzerland from 2016 to 2021. Data were collected initiation chart abstraction, death loss follow-up, whichever came first. time event analysis conducted using the Kaplan-Meier method cumulative rates response, remission, mucosal healing persistence estimated over 12, 24 36 months. Serious adverse events (SAEs), serious infections (SIs), exacerbations CD-related surgeries also evaluated. Inverse probability weighing used balance demographic characteristics across groups. Results 623 (VDZ 347, 276) 31 sites included. Baseline are presented Table 1. Cumulative months similar between VDZ- UST-treated response 82.0%, 84.1%; p=0.87) remission 88.3%, 88.5%; p=0.67) (Table 2). Mucosal significantly higher versus 91.3%, 87.4%, p=0.02), 70.6%, 80.3%; p=0.03). In cohort, 54 SAEs (including SIs) 12 SIs occurred 35/347 (10.1%) 9/347 (2.6%) pts, respectively, while 53 5 27/276 (9.8%) 2/276 (0.7%) respectively. There no significant differences risk (HR 1.01; 95% CI, 0.68-1.49; p=0.98) 1.80; 0.69-4.73; p=0.23) pts. Conclusion setting, CD. However, VDZ-treated