A Study to Evaluate the Efficacy and Safety of CS32582 in Participants With Moderate to Severe Plaque Psoriasis

Prior treatment

• Forms of psoriasis other than plaque-type (e.g., erythrodermic, pustular, guttate, or drug-induced psoriasis) .
• Major surgery within 2 months before randomization or planned during the study.
• Drug/alcohol abuse within 6 months before screening.
• Myocardial infarction, unstable angina, TIA, stroke, PCI, or CABG within 6 months before screening.
• Prosthetic joint infection (unless prosthesis removed/replaced ≥2 months before randomization).
• History of severe bacterial, fungal, or viral infection requiring hospitalization for IV antibiotic or antiviral administration within 2 months before randomization.
• History of live vaccine administration within 2 months before randomization or plans to receive a live vaccine during the study period.
• Evidence of active infection and/or febrile illness requiring systemic anti-infective therapy within 2 weeks before randomization.
• Prior use of TYK2 inhibitors (e.g., deucravacitinib).
• Use of any of the following therapeutic agents within 6 months before randomization:
  • IL-12/23, IL-17, or IL-23 inhibitors (ustekinumab, secukinumab, tildrakizumab, ixekizumab, guselkumab)
  • Rituximab or other B-cell depleting agents
  • Leflunomide
• Use of any of the following therapeutic agents within 3 months before randomization: Integrin pathway modulators (natalizumab) or B/T-cell modulators (alemtuzumab, abatacept, vedolizumab).
• Use of TNF inhibitors (etanercept, adalimumab, infliximab, certolizumab) within 2 months before randomization.
• Any biologic psoriasis therapy within 3 months or 5 half-lives (whichever longer) before randomization.
• Use of systemic non-biologic psoriasis agents and/or any systemic immunosuppressants within 4 weeks before randomization, including but not limited to: apremilast, methotrexate, azathioprine, cyclosporine, JAK inhibitors, 6-thioguanine, mercaptopurine, mycophenolate, hydroxyurea, tacrolimus, oral/injectable corticosteroids, retinoids, calcitriol/analogs, psoralen, sulfasalazine, fumarates).
• Use of Lithium, antimalarials, or intramuscular gold preparations within 4 weeks before randomization.
• Use of any botanical agents for the treatment of psoriasis or other immune disorders within 4 weeks before randomization, including herbal supplements or traditional Chinese medicines derived from plants, minerals, or animals.
• Received phototherapy within 4 weeks before randomization.
• Use of medicated shampoos and/or body washes within 2 weeks before randomization, including but not limited to products containing: corticosteroids, coal tar, \>3% salicylic acid, vitamin D3 analogs.
• Use of any topical agents that may affect psoriasis symptoms within 2 weeks before randomization.
• Received any investigational therapy within 30 days or 5 half-lives (whichever is longer) before randomization, OR current participation in other trial.

Other illness

• Presence of other skin conditions that in the judgement of the Investigator could interfere with study assessment.
• Immune-mediated diseases requiring systemic therapy (e.g., inflammatory bowel disease), except NSAIDs.
• History of severe drug allergies.
• Uncontrolled hypertension at screening (SBP \>160 mmHg or DBP \>100 mmHg).
• NYHA Class III/IV heart failure at screening.
• History of malignancy or lymphoproliferative disorders within 5 years (exceptions: basal cell carcinoma, localized squamous cell carcinoma, or cervical carcinoma in situ cured ≥1 year).
• History of opportunistic infections (e.g., PJP, histoplasmosis, coccidioidomycosis).
• Active/latent TB infection (positive IGRA without clinical manifestations).
• Herpes infection:a) Active herpes zoster/simplex (HSV-1/2) at screening;b) History of severe herpes (disseminated disease, multidermatomal HSV, encephalitis, ophthalmic herpes, or recurrent zoster \[≥2 episodes in 2 years\]).
• Abnormal virology at screening:
  • HBsAg(+) or HBcAb(+) with detectable HBV-DNA
  • HCV Ab(+) with detectable HCV-RNA
  • History of HIV infection or HIV Ab(+)
  • Treponema pallidum Ab(+) with positive RPR/TRUST
• Any condition deemed unsuitable by the investigator.

Lab values

• Laboratory values meeting any of the following criteria during screening or before randomization:
  • Liver: ALT/AST ≥3×ULN; total bilirubin \>2×ULN
  • Hematology: WBC \<3.0×10⁹/L (3000/mm³); ANC \<1.0×10⁹/L (1000/mm³); lymphocyte count \<0.5×10⁹/L (500/mm³); platelets \<100×10⁹/L (100,000/mm³); hemoglobin \<9.0 g/dL (90 g/L)
  • Renal: eGFR \<60 mL/min/1.73m² (CKD-EPI equation)

Other

• Pregnant or lactating women.

• Voluntarily sign the informed consent form (ICF) after fully understanding the trial.
• Age 18-70 years (inclusive) at consent, any gender
• Clinically diagnosed with chronic plaque psoriasis, defined as disease duration ≥ 6 months at screening.
• Stable plaque psoriasis at screening, defined as no significant flare-ups or morphological changes during the 6 months prior to screening (investigator-assessed).
• Moderate-to-severe disease at screening/randomization: PASI≥12, sPGA≥3, and BSA≥10%;
• Candidate for phototherapy or systemic therapy per investigator's judgment.
• Women of childbearing potential and males: Agreement to use highly effective contraception from consent until 30 days post-last dose.