A Phase III Study of SYHX1901 Tablets in the Treatment of Moderate to Severe Plaque Psoriasis

The purpose of this study is to evaluate the efficacy and safety of different doses of SYHX1901 tablets in the treatment of moderate to severe plaque psoriasis.

This is a multicenter, randomized, double-blind, placebo-controlled phase III study to evaluate the efficacy and safety of three different doses of SYHX1901 tablets compared with placebo in the treatment of moderate to severe plaque psoriasis. The total duration of the study will be 60 weeks which will be comprised of: a screening period (4 weeks); a core treatment period (16 weeks), a extended treatment period（36 weeks）and a follow-up assessment period (4 weeks). Eligible subjects will be randomly assigned to SYHX1901 dose 1 , dose 2 or placebo group at a 2:2:1 ratio for continuous oral administration for 16 weeks，then placebo group will will be randomly assigned to SYHX1901 dose 1, dose 2 at a 1:1 ratio for continuous oral administration for 36 weeks, the SYHX1901 dose 1, dose 2 group will remain the same dose for 36 weeks. The presence or absence of prior treatment with biological agents will be a stratification factor. Subjects will be monitored for the efficacy and safety throughout the study.