his study is a randomized, double-blinded, and placebo-controlled phase Ia clinical study in subjects with SLE. The study is designed to assess the safety and tolerability of IASO-782 for the treatment of SLE.

This study is a multiple-dose escalation study in subjects with SLE. The study is designed to enroll subjects with SLE. This study will evaluate the safety and preliminary dose range of IASO-782 in subjects with SLE at the following dose levels:4mg/kg，6mg/kg and 10mg/kg.

Inclusion Criteria:

1. Aged 18 to 75 years;
2. Clinically confirmed diagnosis of SLE before screening;
3. Currently receiving standard treatment regimens, including any single drug or combination of drugs;
4. Organ function or laboratory test is basically normal;
5. Subjects with potential fertility and their partners must use effective contraceptive measures for at least 2 weeks before the first dose of the study drug, throughout the study period, and for 6 months after the end of the study (or early termination of the study);
6. Females with potential fertility must have a negative pregnancy test during the Screening Phase;
7. Voluntarily participate in the study and sign the informed consent form.

Exclusion Criteria:

1. History of other primary malignant neoplasm within 5 years of screening;
2. A history of cardiac disease within the recent 3 months, including New York Heart Association (NYHA) Class III/IV congestive heart failure and cardiac arrhythmias requiring drug treatment;
3. Subjects with poorly controlled hypertension despite drug treatment;
4. A history of hypersensitivity to any component of the study drug or its excipients confirmed before screening;
5. Presence of active infection requiring intravenous drug treatment within 30 days before screening;
6. Pregnant or lactating females;
7. Participation in any other clinical trial within 28 days before randomization or within 5 half-lives of the study drug in the other trial (whichever is longer);
8. Previous treatment drugs have not been adequately washed out;
9. A previous history of any arterial or venous thrombosis (stroke, transient ischemic attack, myocardial infarction, deep vein thrombosis or pulmonary embolism), or clinical symptoms and medical history suggesting thrombophilia; or any of the following: cardiac arrhythmias known to increase the risk of thrombotic events (e.g., atrial fibrillation), or a corrected QT interval (QTc) >450 msec in the subject; or a history of other coagulation abnormalities;
10. Confirmed diagnosis of severe lupus nephritis within 8 weeks before screening (defined as urine protein >6 g/24 hours or serum creatinine >2.5 mg/dL or 221 μmol/L), or requiring treatment with study-prohibited drugs, or having active nephritis requiring prednisone ≥100 mg/day or equivalent glucocorticoid for ≥14 days; active severe or unstable neuropsychiatric SLE, including but not limited to poorly controlled seizures, psychosis or acute confusional state, cerebrovascular accident, demyelinating syndrome, cranial nerve palsy, or evidence of active central nervous system vasculitis within 12 weeks before the screening visit;
11. Hepatitis B virus (HBV) infection during the Screening Phase (if HBsAg is positive, or HBsAg is negative but anti-HBc is positive, HBV-DNA testing is required, and the subject will be excluded if viral replication is indicated); positive anti-hepatitis C virus (HCV) antibody with positive peripheral blood HCV RNA; positive human immunodeficiency virus (HIV) antibody; positive specific treponema pallidum antibody with positive rapid plasma reagin test;
12. Tuberculosis (TB) infection: TB testing will be appropriately performed during screening according to local clinical practice. Subjects with active tuberculosis will be excluded, except for those with latent TB who are judged by the investigator to be eligible for the study;
13. A history of substance abuse or mental disorders;
14. Any other medical history or condition judged by the investigator to be unsuitable for study participation.