Inclusion Criteria:
1. Aged ≥ 18 years at the time of signing the informed consent form (ICF), male or female
2. Body mass index was ≥18 kg/m ² at screening
3. A history of plaque psoriasis ≥6 months before randomization, with or without psoriatic arthritis
4. Inadequate response to at least one biologic agent administered at full dose and on a regular schedule prior to screening
5. tParticipants with plaque psoriasis deemed by the investigator suitable for continued biologic therapy
6. Participants voluntarily sign informed consent before the start of any procedures related to the study, able to communicate smoothly with the investigator, understand and comply with the study protocol requirements
Exclusion Criteria:
1. Diagnosis of psoriasis other than chronic plaque psoriasis at screening or baseline
2. Drug-induced psoriasis
3. Other skin conditions that, in the investigator's opinion, would interfere with psoriasis assessment
4. Concurrent other active autoimmune diseases
5. Prior exposure to drugs targeting the IL-36 receptor
6. Prior exposure to drugs targeting IL-23p19
7. Systemic treatment other than biological agents was received within 4 weeks before baseline
8. Topical treatment for psoriasis was received within two weeks before the baseline
9. Received photochemotherapy within 4 weeks before baseline, or received phototherapy within 2 weeks before baseline
10. Have participated in any clinical study of a drug or medical device within 3 months prior to baseline or within 5 half-lives of the drug
11. The participants had a previous history of lymphocytic hyperplasia
12. Participants had any history of active malignant tumors or malignant tumors within the five years prior to screening
13. Participants with a history of moderate to severe congestive heart failure, cardiovascular and cerebrovascular events, or severe bleeding events within 3 months prior to screening were considered unsuitable for clinical research by the researchers
14. There was a history of opportunistic infection or immunodeficiency disease within 6 months prior to screening
15. If there was an active infection within 2 weeks before baseline requiring oral anti-infection treatment, or if there was a severe infection or systemic infection within 4 weeks before baseline requiring intravenous anti-infection treatment or hospitalization due to infection, or other chronic, recurrent, and active infections that the researcher judged as unsuitable for participation in this study
16. There is active tuberculosis or latent tuberculosis infection
17. Positive human immunodeficiency virus antibody (HIV), or positive hepatitis C virus (HCV) antibody test and positive quantitative hepatitis C ribonucleic acid (HCV-RNA) during screening; Or positive for hepatitis B surface antigen (HBsAg)
18. Patients with severe, progressive, uncontrolled cardiovascular and cerebrovascular, liver, kidney, lung, gastrointestinal, hematopoietic system, endocrine, nervous system, mental system, skin and mucous membrane diseases, etc., as well as other conditions that researchers consider unsuitable for participation in this trial
19. The following situations occur in laboratory tests and/or 12-lead electrocardiogram (ECG) during screening:
Aspartate aminotransferase (AST) or ALT is three times or more greater than the upper limit of the normal value (ULN).
Total bilirubin \> 1.5 times ULN; Serum creatinine \> 1.5 times ULN; The hemoglobin level was less than 85.0 g/L for male participants and less than 80.0 g/L for female participants.
White blood cell count \< 3.0 \*109/L; Neutrophil count \< 1.5 \*109/L; Platelet count \< 100\*109/L; The 12-lead ECG examination indicated clinically significant abnormalities that might affect the safety of the participants, including but not limited to acute myocardial ischemia, myocardial infarction, and severe arrhythmia.
20. Pregnant or lactating female, or testing positive for human chorionic gonadotropin (hCG)
21. Allergic to the investigational drug (including SHR-1139 injection and placebo) or any component in the investigational drug; Or those with a clear history of allergy to monoclonal antibodies or drugs targeting the same action; Or those with a history of severe drug allergies
22. There was a history of alcohol abuse or illegal drug abuse within one year prior to the screening
23. Those who received a live attenuated vaccine within 12 weeks before randomization, or intended to receive a live attenuated vaccine during the study period, or participated in a vaccine clinical trial within 12 weeks before randomization
24. Donate approximately 500 mL of blood within the 8 weeks prior to randomization or have a blood donation plan during the study period
25. Those who have undergone major surgery within 8 weeks prior to screening or have relevant surgical plans during the study period
26. The researchers judged that there were situations that affected the safety and efficacy evaluation of the investigational drug
