A Study of SCTB35 in Patients with Systemic Lupus Erythematosus

Inclusion criteria

• Age 18-75 years；
• Diagnosed with SLE for ≥12 weeks prior to screening (2019-ACR/EULAR criteria);
• SLEDAI-2K ≥ 8 at screening, or ≥6 if there is hypocomplementemia or elevated anti-dsDNA antibody levels;
• Positive for ANA (1:80) or positive for anti-dsDNA and/or anti-Sm antibodies within the last 12 months or at screening;
• Currently receiving ≥1 stable dose of standard treatment: oral corticosteroids, antimalarials, or conventional immunosuppressive drugs
• Stable corticosteroid dose for ≥4 weeks prior to baseline;
• Stable dose of antimalarial drugs for ≥4 weeks prior to baseline;
• Stable dose of immunosuppressive agents for ≥4 weeks prior to baseline;
• All male participants or females of reproductive potential must agree to use reliable contraception with their partner from signing the ICF through 6 months after the last dose of the study drug;
• Understanding of the study procedures and voluntary signing of the informed consent form.

Exclusion criteria

• Severe active or unstable lupus-related neuropsychiatric disorders;
• Other autoimmune diseases that may interfere with efficacy evaluation;
• Catastrophic antiphospholipid syndrome;
• Received treatments that may affect the drug's effect:
• Received live vaccines or attenuated vaccines within 28 days prior to baseline or screening;
• Clinically significant bleeding risk;
• Abnormal laboratory results:
• AST or ALT \>2.5 x ULN;
• Total bilirubin \>1.5 x ULN;
• ANC \<1.5x10⁹/L;
• Platelets \<75x10⁹/L;
• Hemoglobin \<100g/L;
• eGFR \<30 mL/min/1.73 m²;
• Positive serum HCG;
• Received any investigational treatment within 30 days prior to baseline or within 5 half-lives of the investigational drug (whichever is longer);
• Participants with recurrent, chronic, or other active infections as assessed by the investigator;
• Severe or uncontrolled disease, which would prevent participation in the study;
• Positive viral serology tests, including HIV, HCV, and HBV;
• Tuberculosis screening: Known active tuberculosis or latent tuberculosis infection (LTBI);
• Any type of active infection except nail bed fungal infections;
• Severe infections;
• History of progressive multifocal leukoencephalopathy (PML);
• Diagnosed with type 1 or type 2 diabetes with poor control;
• Uncontrolled hypertension (systolic \>140 mmHg or diastolic \>90 mmHg);
• History of malignancy within 5 years prior to baseline;
• Alcohol abuse or drug misuse within 12 months prior to screening;
• Intolerance to the study drug or contraindications, including a history of severe allergic reactions to monoclonal antibodies or any component of SCTB35 injection;
• Required hospitalization for major surgery within 4 weeks prior to screening or within 12 weeks post-study drug administration;
• Participants with mental disorders or poor compliance;
• Severe lupus nephritis;
• History of solid organ or hematopoietic stem cell/bone marrow transplant, or expected to undergo transplant surgery during the study;
• Pregnant or breastfeeding;
• Any other condition that the investigator deems unsuitable for participation in the study.