This phase will commence following dose escalation in the 24mg bid group during Phase I. Employing a 1:1:1 randomized, double-blind, placebo-controlled study design, it will evaluate the efficacy, safety, and Pharmacokinetics/Pharmacodynamics (PK/PD) characteristics of TQH3906 capsules in subjects with moderate-to-severe active ulcerative colitis. The study will include a maximum 4-week screening period, a 12-week treatment period, and a 4-week post-treatment follow-up period, enrolling a total of 105 subjects. Among these, subjects who failed conventional therapy and those who failed biologic therapy each constitute 35% of the cohort.
week treatment period, and a 4-week post-treatment follow-up period. A total of 105 subjects will be enrolled, with 50% comprising subjects who failed conventional therapy and 50% comprising subjects who failed biologic therapy.
Dose Group Design:
Group A: Placebo Group B: 32mg dose group Group C: 24mg bid dose group The specific dose will be determined based on the 48mg dose group's medication experience from Phase I and adjusted as necessary.
Age between 18-75 years (inclusive of both 18 and 75), regardless of gender.
Diagnosed with ulcerative colitis or Crohn's disease for ≥3 months, as assessed by histological or endoscopic examination prior to screening.
Active moderate to severe UC or CD.
Subjects must have failed at least one of the following drug treatments for UC or CD or be intolerant: oral aminosalicylates, oral corticosteroids, immunosuppressants, biologics, etc.
Pregnant or lactating women.
Lesions confined solely to the rectal segment within 15 cm of the anus.
Subjects diagnosed with indeterminate colitis, radiation colitis, or ischemic colitis.
Presence of severe complications such as local stricture, intestinal obstruction, intestinal perforation, major lower gastrointestinal hemorrhage, intestinal neoplastic changes or neoplastic potential, toxic megacolon; rectal/colonic polyps, or anal diseases that the investigator assesses may impact efficacy and safety evaluation.