Hemay005 for the Treatment of Chinese Moderately to Severely Active Ulcerative Colitis

This study is a phase 3, multicenter, randomized, double-blinded, placebo-controlled, parallel-group study to examine the efficacy, safety of Hemay005 in induction and maintenance therapy in Chinese patients with moderately or severely active ulcerative colitis. The study consists of two independent phases: an 12-week Induction Phase (might including an 12-week Extended Induction phase, depending on the participant status by the end of the induction treatment) and a 40-week Maintenance Phase. Screening period will be up to 5 Weeks.

In the Induction Phase, participants will be randomized 2:1 to receive either Hemay005 (twice daily) or placebo for 12 weeks. The randomization will be stratified by: exposed to advanced therapy (yes/no); disease severity (modified Mayo score of 5-6 or 7-9) and baseline corticosteroid use (yes/no). Participants who have not show clinical response (either receive Hemay005 or placebo) by week 12 will undergo an extended 12-week induction treatment with Hemay005.

After completing the Induction Phase (or the Extended Induction Phase), participants with response are eligible to go to the Maintenance Phase. Participants with a response to Hemay005 by week 12 of the Induction Phase and those with a response by the end of the Extended Induction Phase) will be randomized 1:1 to receive either Hemay005 (twice daily) or placebo for 40 weeks. Randomization will be stratified by corticosteroid use at the start date of Maintenance Phase (yes/no) and clinical remission status by the end of Induction Phase (yes/no). Participants who are assigned to placebo during the Induction Phase and have demonstrated a clinical response will continue to receive blinded placebo during the Maintenance Phase. Participants who have not showed a clinical response by week 12 of the Induction Phase but have a response to Hemay005 by the end of the Extended Induction Phase will continue to receive blinded Hemay005 during the Maintenance Phase.

During the Maintenance Phase, participants who are demonstrated loss of response will be eligible to go to the open-label treatment phase and treated with Hemay005. The total duration of open-label treatment phase will not exceed 40 weeks since the participant enrolled into the Maintenance Phase.