Ustekinumab trough concentration affects clinical and endoscopic outcomes in patients with refractory Crohn's disease: a Chinese real-world study.

Background: Ustekinumab (UST), a newly-used biologic targeting p40 subunit of IL12 and IL23 in China, exerts a confirmed therapeutic effect on the induction and maintenance therapies for refractory Crohn's disease (CD). Therapeutic drug monitoring based on trough and antibody concentration is of core importance when treating patients who lose response to UST. We aimed to analyze the UST exposure-response relationship in CD treatment in the real-world setting.