The purpose of this study is to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of HX15001 injection combined with Etrasimod tablets in participants with moderately to severely active ulcerative colitis (UC).
Patient able to read and understand, and willing to sign the informed consent form;
Weight≥40kg;
Clinical diagnosis of Ulcerative colitis (UC) that has been present for at least 3 years before the screening visit;
Mayo score of 5-9 at the baseline visits, including Mayo Endoscopic Score ≥2 and Rectal Bleeding Subscore ≥1, and disease extent from the anal verge ≥ 15 cm at screening.
Evidence or history (within 6 months) of fulminant colitis, toxic megacolon, or intestinal perforation.
Prior colectomy (partial or total), or anticipated need for surgical intervention for UC during the study.
Prior or current diagnosis of Crohn's disease, fistulas/abscesses, indeterminate colitis, unclassified IBD, microscopic colitis, ischemic colitis, infectious colitis, radiation colitis, active diverticulitis, or other colitis/enteritis that may confound efficacy assessment.
Current unresolved colonic dysplasia, adenoma, adenomatous polyps, or neoplastic lesions. Patients with history of adenomatous polyps are eligible if polyps were completely removed (documented) and screening colonoscopy/histology shows no residual polyps or dysplasia.