Efficacies and Related Issues of Ustekinumab in Japanese Patients with Crohn's Disease: A Preliminary Study

Introduction: Ustekinumab (UST) is an antibody to the p40 subunit of interleukins 12 and 23 in Crohn's disease (CD) patients. Few reports are available on CD in the Asian scenario. Objective: We evaluated UST's efficacy in inducing remission and its maintenance in Japanese CD patients. Methods: This retrospective study was conducted in UST-treated CD patients at our center. The primary endpoint was the clinical remission rate at week 8; the major secondary endpoints were the clinical remission rate at week 24 or 48, change in CD activity index (CDAI) and biomarkers, endoscopic efficacy, and cumulative remission maintenance rate. Results: The clinical remission rates at weeks 8, 24, and 48 were 44.4, 66.7, and 50.0%, respectively. Delayed response was shown by 22.2% of the patients; they achieved remission by week 24. The baseline CDAI was significantly lower in the remission group than in the nonremission group at week 8 (95% CI 0.89-0.99; p = 0.03). The cumulative remission maintenance rates at 6 and 12 months were 82.4 and 49.8%, respectively. Loss of response (LOR) was noted in 22.2% of the patients within 1 year. The endoscopic response and mucosal healing rate were 52.6 and 5.3%, respectively. Rapid improvements in serum albumin levels were observed at weeks 8 (p = 0.06), 24 (p < 0.01), and 48 (p = 0.01) from the baseline in active cases at baseline. Conclusions: UST is effective for remission induction and maintenance, especially in those with lower CD activity, however, may result in delayed response or LOR.