Safety and effectiveness of ustekinumab in Crohn's disease: Interim results of post‐marketing surveillance in Japan

BACKGROUND AND AIM: Ustekinumab, a human anti‐interleukin‐12/23 monoclonal antibody, has been approved in Japan for the treatment of Crohn's disease. Here, we report the findings from an 8‐week interim analysis of post‐marketing surveillance to evaluate the safety and effectiveness of ustekinumab in Japanese patients with Crohn's disease. METHODS: Patients initiating ustekinumab treatment were prospectively evaluated from May 2017 to June 2020 at 91 medical centers in Japan. Adverse drug reactions (ADRs) and serious ADRs (SADRs) were monitored. Effectiveness was evaluated by clinical response, clinical remission, and changes in Crohn's Disease Activity Index (CDAI) and C‐reactive protein (CRP) from baseline to week 8. Presence of perianal disease was documented at baseline and week 8. RESULTS: In total, 341 patients were enrolled in the study, of which 339 were included in the safety analysis while 334 were included in the effectiveness analysis. The overall incidences of ADRs and SADRs were 5.3% and 2.1%, respectively. Worsening of Crohn's disease was the most common event. The clinical response and clinical remission rate at week 8 were 40.0% and 48.5%, respectively. Significant improvements in CDAI and serum CRP (P < 0.001) were observed at week 8. CDAI decreased significantly (mean difference: −31.4; 95% confidence interval: −61.1, −1.7; P = 0.038) in biologics‐naïve patients versus patients who had received two or more biologics. CONCLUSIONS: This 8‐week interim analysis of the real‐world study confirmed the effectiveness of ustekinumab‐based therapy in Japanese patients with Crohn's disease. No new safety concerns were found during 8‐week induction period in the Japanese clinical settings.