Efficacy of Ustekinumab Therapy in Patients With Symptomatic Stricturing Crohn's Disease

Inclusion Criteria: * Clinical diagnosis of moderate to severe Crohn's disease * Obstructive symptoms within the last eight weeks * A single or several lumen stricture(s) identified by radiological imaging or endoscopy * For strictures identified by CT enterograph defined as a lesion with combination of a reduction of luminal narrowing \>50%, an increase in bowel wall thickness \>25% relative to non-affected bowel and pre-stricture dilation \>3.0 cm * For strictures identified during endoscopic procedure defined by intestinal strictures with a lumen diameter ≤12 mm or even inability to pass the endoscope across the narrowing Exclusion Criteria: * Requirement of urgent surgery or endoscopic intervention within 2 months as judged by the clinician * Symptoms or signs of perforation such as active perianal sepsis, abdominal abscess, intestinal fistula, and abdominal adhesions * Intestinal obstruction caused by surgery, intra-abdominal abscess, isolated intestinal stricture * Effective treatments for stricture in the past half a year, such as endoscopic balloon dilatation, intestinal stricture plasty, surgery/manual anal dilatation, etc. * Unable to eat after using enteral nutrition for more than 2 months * History of ustekinumab (UST) or other IL-23 antagonists use in the past 12 months * CT enterograph contraindications, such as allergy to contrast media * Relative contraindications of biological agents, such as pulmonary tuberculosis-positive chest X-ray or active tuberculosis with strong positive tuberculin skin test, myocardial infarction, heart failure, or demyelinating neurological disease * Currently suffering from a solid tumor, lymphoma, or melanoma and undergoing chemotherapy or radiation therapy * Combination of intestinal dysplasia (eg, diagnosed with short bowel syndrome), colostomy, or colorectal tumors * Combination of active gastrointestinal bleeding, shock, severe diarrhea, refractory vomiting and severe malabsorption syndrome * Combination of severe liver and kidney dysfunction * Coexistence of bacterial or viral active infection * Pregnant or breastfeeding * Severe hemodynamics, unstable vital signs or presence of rapidly progressive or end-stage disease, expected to be fatal during the course of the study