Inclusion Criteria:
1. During the screening process, the body mass index (BMI = weight (kg) / height\^2 (m\^2)) was ≥ 18 kg/m\^2;
2. History of plaque psoriasis for more than 6 months before randomization；
3. The PASI score, sPGA score, and BSA at the screening and baseline required certain requirements;
4. Participants suitable for phototherapy or systemic psoriasis treatment for moderate to severe plaque psoriasis;
5. Participants voluntarily signed the informed consent before any procedures related to the study, could communicate smoothly with the researchers, understood and were willing to strictly follow the requirements of this clinical study protocol to complete the study;
6. Female participants with reproductive capacity or their male partners with reproductive capacity, starting from the date of signing the informed consent until 72 weeks after the last medication, had no plans for pregnancy, sperm donation, or egg donation, and voluntarily took effective contraceptive measures. The pregnancy test results of female participants during the screening period and before random administration should be negative, and must be non-lactating.
Exclusion Criteria:
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The following conditions or diseases must be absent:
1. The diagnosed psoriasis at the screening or baseline stage is not chronic plaque-type psoriasis;
2. Has drug-induced psoriasis;
3. Has other skin problems that the investigator considers would interfere with the assessment of psoriasis;
4. Has concurrent other active autoimmune diseases, including but not limited to rheumatoid arthritis, systemic lupus erythematosus, scleroderma, polymyositis, multiple sclerosis or other central demyelinating diseases, primary Sjögren's syndrome, etc.;
Using the following drugs or participating in clinical studies:
1. During the pre-baseline period, other biological agents had been used but did not meet the washout requirements.
2. Has used drugs targeting the same target before the screening;
3. Has received systemic psoriasis treatment drugs within the specified period before the baseline;
4. Has received topical psoriasis treatment drugs within the specified period before the baseline;
5. Has received phototherapy within the specified period before the baseline;
6. Has participated in any clinical study of drugs or medical devices within 3 months before the baseline or within the drug's half-life period;
Important conditions or underlying diseases that affect safety:
1. The participant has a history of lymphocytic proliferative diseases;
2. The participant has had any active malignant tumor or history of malignant tumor within the previous 5 years before the screening;
3. Has a history of moderate to severe congestive heart failure (NYHA cardiac function classification ≥ III) within 3 months before the screening, has experienced cardiovascular or cerebrovascular events or severe bleeding events, and the investigator considers this participant unsuitable for participating in the clinical study;
4. Has had opportunistic infections or immunodeficiency diseases within the previous 6 months before the screening;
5. Has had active infections requiring oral anti-infection treatment within 2 weeks before the baseline, or has had severe infections or systemic infections within 4 weeks before the baseline, requires intravenous anti-infection treatment or is hospitalized due to infection, or other chronic, recurrent, active infections that the investigator deems unsuitable for participation in this study;
6. Has active tuberculosis (TB) or latent TB infection;
7. Has human immunodeficiency virus antibody (HIV) positive at screening, or hepatitis C virus (HCV) antibody positive and further HCV-RNA quantitative positive; or hepatitis B surface antigen (HBsAg) positive; or HBsAg negative but HBcAb positive, and further HBV-DNA test positive; or Treponema pallidum specific antibody positive.
8. Has severe, progressive, uncontrolled cardiovascular, liver, kidney, lung, gastrointestinal, hematopoietic system, endocrine, nervous system, mental system (such as depression, suicidal tendency and psychological disorders), skin and mucous membrane diseases, and other conditions that the investigator considers that the patient is not suitable to join this trial;
9. Laboratory tests and/or 12-lead electrocardiogram (ECG) results are abnormal at screening:
General situation:
1. Pregnant or lactating women;
2. Allergic to any component of the test drug;
3. Had a history of alcohol abuse or illegal drug use within the previous year before the screening;
4. Had blood donation of approximately 500 mL within the previous 8 weeks before randomization or had a blood donation plan during the study;
5. Had major surgery within the previous 8 weeks before screening, or had related surgery plans during the study;
6. The investigator judges that there are other situations that affect the safety and efficacy evaluation of the test drug.
