P374 Real-life effectiveness and safety of ustekinumab treatment in patients with ulcerative colitis: An Asan-Crohn’s and Colitis Association in Daegu-Gyeongbuk (CCAiD) multicenter cohort study

Background The real-life data on ustekinumab (UST) for Asian patients with ulcerative colitis (UC) are limited. We aimed to assess effectiveness and safety of UST for Korean patients with UC. Methods This was a multicenter retrospective study on patients with UC who received UST at 4 academic centers in Korea between January 2021 and April 2023. The primary endpoint was clinical remission defined as partial Mayo score (PMS) ≤2 and no subscore >1 at week (W) 8 of therapy. Secondary endpoints included clinical remission (W16–20 and W52–56), corticosteroid-free clinical remission (W8, W16–20 and W52–56), clinical response defined as reduction of PMS ≥3 and at least 30% from baseline with either a decrease in rectal bleeding subscore ≥1 or an absolute rectal bleeding subscore ≤1 (W8, W16–20 and W52–56), endoscopic remission defined as Mayo endoscopic subscore 0–1 (W16–20 and W52–56), durability of UST at W52–56 and adverse events. Results A total of 55 patients were included and 54 were analyzed excluding one in clinical remission at baseline (Male, 66.7%; Median age at UST initiation, 44.5 years; Disease duration at UST initiation, 7.5 years; Previous exposure to biologics/small molecules, 70.4%; Extensive colitis, 64.8%; Median baseline Mayo score, 8; Concomitant use of systemic corticosteroids, 48.1%; Concomitant use of immunomodulators, 38.9%). Out of 54 patients, 27 patients (50%) reached to W52–56 or stopped UST, while remained 27 patients still under maintenance UST therapy, not reaching W52–56. At W8, W16–20, and W52–56, 53.7% (29/54), 63% (34/54), and 44.4% (12/27) achieved clinical remission and 68.5% (37/54), 70.4% (38/54), and 51.9% (14/27) showed clinical response, respectively (Figure 1). Endoscopic remission rates at W16–20 and W52–56 were 57.4% (31/54) and 37% (10/27), respectively (Figure 1). The durability of UST at W52–56 was 74.1% (20/27). Multivariable analysis revealed that previous exposure to biologics/small molecules was negatively associated with clinical remission at W8 (OR: 0.10; 95% confidence interval [CI] 0.02–0.57; p=0.01) and W16–20 (OR: 0.18; 95% CI 0.04–0.91; p=0.04), whereas the concomitant use of immunomodulators showed a positive association with clinical remission at W8 (OR: 4.19; 95% CI 1.11–15.77; p=0.03). Adverse events occurred in 23 patients (42.6%) and serious adverse event in one patient (1.9%) (Table 1). Conclusion UST was effective with an acceptable safety profile for Korean patients with UC. Previous exposure to biologics/small molecules was negatively associated with clinical remission at both W8 and W16–20. Financial Support This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (NRF-2021R1A2C2095096).