The primary objective of this study is to evaluate the efficacy and safety of HS-20137 in the treatment of participants with moderate to severe plaque psoriasis.

HS-20137 is an antibody targeting IL-23, which were recommended biologic agents for the treatment of patients with moderate-to-severe psoriasis. This is a randomized, double-blinded, placebo-controlled phase 3 study, including a 4 weeks screening period, a 52 weeks double-blinded period (placebo-control period in the first 16 weeks) and a 8 weeks follow-up period (total 60 weeks). The hypothesis is that HS-20137 will be more effective in treatment of psoriasis than placebo and well tolerated. Participants with moderate-to-severe plaque psoriasis will be included in this study and received HS-20137 200mg or placebo in week 0, 4, 8 in placebo-control period and then HS-20137 200mg every 8 or 12 weeks thereafter.

Inclusion Criteria:

1. Adults aged 18 and above, male or female;
2. Diagnosed plaque psoriasis for at least 6 months before randomization, with or without psoriatic arthritis;
3. During screening and randomization, the severity of plaque psoriasis was moderate to severe, and the following conditions should be met: a) BSA≥10%; b) PASI≥12; c) sPGA≥3;
4. Suitable for systemic therapy or phototherapy;
5. Voluntarily participate in the research, have the ability and willingness to complete the research according to the research protocol, and sign the informed consent.

Exclusion Criteria:

1. Previous use of biological agents, or allergic reactions to known drug ingredients, or previous severe food or drug allergies;

2. Confirmation of other types of psoriasis, including but not limited to guttiform psoriasis, pustular psoriasis, erythrodermic psoriasis, drug-induced exacerbation of psoriasis (including beta-blockers, non-steroidal anti-inflammatory drugs, antimalarial drugs, interferon, calcium channel blockers, or lithium induced psoriasis) from the screening period to the time before randomization;

3. Other skin lesions, chronic inflammatory diseases or autoimmune diseases, including but not limited to systemic lupus erythematosus, Sjogren's syndrome, skin sclerosis, etc., assessed by the investigator and other factors that may affect the efficacy evaluation or assessed by other researchers before randomization;

4. Primary treatment failure occurred with previous use of similar investigatory drugs (including marketed ulinumab, gusecciumab, Tiricizumab, Lisenciumab, and IL-23 target investigatory drugs under development) (the minimum treatment standard was not reached 12 weeks after the first treatment);

5. Use of the following drugs before randomization:

   1. Use of topical treatment drugs that affect the evaluation of psoriasis within 2 weeks before randomization;
   2. 4 weeks before randomization, Use of phototherapy, traditional systemic therapy drugs, small molecule targeted drugs that may affect the evaluation of psoriasis;
   3. use of TNF-α biologics within 3 months prior to randomization;
   4. use of other biologics for the treatment of psoriasis within 6 months before randomization; e) Use of oral or topical proprietary Chinese medicinesor other Chinese herbal medicines that affect or may affect the evaluation of psoriasis within 4 weeks prior to randomization;

   f) use of lymphocyte migration regulators or B cell and T cell regulators within 3 months before randomization, or 6 months before screening, (whichever is older) use of B-cell-specific scavenging drugs;

6. A history of chronic recurrent infection, or opportunistic infection in the 6 months prior to screening, or hospitalization for a serious infectious disease or intravenous antibiotic use in the 2 months prior to randomization, with a confirmed or suspected illness in the 1 week prior to randomization. And Other circumstances determined by the investigator to be unsuitable for further study participation.