Comparative Effectiveness and Safety of Risankizumab vs Ustekinumab in Crohn's Disease: A Real-World Retrospective Cohort Study from Taiwan.

Background: Direct real-world comparative data on risankizumab and ustekinumab for Crohn's disease are limited, particularly in Asian populations and in patients with fistulizing disease. These agents are clinically important comparators because both target the IL-23 pathway but differ mechanistically, with ustekinumab blocking the shared IL-12/23 p40 subunit and risankizumab selectively blocking IL-23 p19. Methods: We conducted a retrospective single-center cohort study of consecutive adults with Crohn's disease who initiated risankizumab or ustekinumab in Taiwan between January 2020 and December 2025. Ustekinumab was given as weight-based intravenous induction followed by 90 mg subcutaneous maintenance, and risankizumab as 600 mg intravenous induction at weeks 0, 4, and 8 followed by 360 mg subcutaneous maintenance every 8 weeks, with routine-care modifications permitted. The primary outcome was steroid-free clinical remission at week 24, defined as CDAI <150 without steroids. Secondary outcomes included clinical remission through week 52, laboratory changes, hospitalization, surgery, fistula closure, and adverse events. Results: Among 285 patients, 58 received risankizumab and 227 received ustekinumab. The risankizumab group had more smoking, penetrating disease, extraintestinal manifestations, prior complications, and prior biologic exposure, suggesting a more refractory population. At week 24, steroid-free clinical remission was lower with risankizumab than ustekinumab among patients with available data (46.7% vs 82.4%, P<0.001). This difference was most evident in biologic-naïve patients (54.5% vs 93.9%, P<0.001), while no significant difference was observed in biologic-experienced patients. Fistula closure was more frequent with risankizumab (75.0% vs 29.4%, P=0.002), and reported adverse events were less frequent (0% vs 24.3%, P<0.001). Hospitalization, surgery, and laboratory changes were similar. Conclusion: In this Taiwanese real-world cohort, ustekinumab was associated with higher week-24 steroid-free remission, particularly in biologic-naïve patients, whereas risankizumab showed higher fistula closure and fewer reported adverse events. Findings require cautious interpretation due to retrospective design, baseline imbalance, and potential confounding.