Long-term effectiveness and persistence rate of ustekinumab dose intensification in a South East Asian inflammatory bowel disease center.

Background And Aims: Ustekinumab (UST) is an effective biologic for treatment of inflammatory bowel disease (IBD). However, some patients treated with UST have suboptimal clinical response with standard dosing. The aims of this study were to determine the effectiveness of UST dose intensification (DI), identify factors associated with DI, cumulative incidence of DI and persistence of UST among treated patients.

Methods: Clinical data of patients with Crohn's disease (CD) and ulcerative colitis (UC) who received UST from September 2017 to October 2022 in Singapore General Hospital were collected. Primary outcome was defined as achieving corticosteroid-free clinical remission, biochemical remission, endoscopic healing and/or transmural healing (CD). Statistical analysis was performed to identify factors, which are predictive of UST DI and effectiveness of UST DI.

Results: Forty-two patients (34 CD and 8 UC) underwent UST DI to either 6-weekly (n = 19, 45.2%) or 4-weekly (n = 23, 35.9%) and the median time to intensification was 31.1 weeks (17.8-65.7). Presence of perianal disease in CD (HR 4.9; 1.47-16.4) was associated with DI. After DI, 16 (38%) patients achieved primary outcome by week 52. The overall drug persistence rates at 1 year and 2 years were 75.7% (95% CI 62.9-84.6) and 63.5% (95% CI 49.9-74.3), respectively.

Conclusion: Two third of IBD patients underwent DI while on UST treatment and the median time to DI was about 6 months after induction. CD patients with perianal disease is more likely to undergo DI. More than one third of dose-intensified patients achieved remission by week 52.