The Purpose of This Study is to Evaluate the Efficacy and Safety of 626 in the Treatment of SLE

Inclusion Criteria: * Able to understand protocol requirements and sign a written ICF. * Male or female subjects aged 18-70 years when signing the ICF. * Body weight between 40 and 90 kg. * Diagnosed with SLE at least 6 months before the Screening Visit by a qualified physician，confirmed according to the 2019 SLE European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for SLE. * At screening, meet at least one of the following criteria: 1. Anti-nuclear antibody (ANA) titer ≥ 1:80; 2. Positive anti-dsDNA antibody.. * Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) ≥6 with clinical SLEDAI score ≥4 points at Screening and Baseline Visit . * Currently receiving at least one of the SOC SLE medications: oral corticosteroid, antimalarial and/or immunosuppressive agent. Exclusion Criteria: * Study participant has a mixed connective tissue disease, and/or overlap syndrome of systemic lupus erythematosus (SLE) with systemic sclerosis. * Study participant has any medical or psychiatric condition (including conditions due to neuropsychiatric SLE) that, in the opinion of the Investigator, could jeopardize or would compromise the study participant's ability to participate in this study. This includes study participants with a life-threatening condition * Patients who have active Hepatitis B, Hepatitis C or HIV infections as determined by positive results at Screening. * History of cancer. * Active severe lupus nephritis present within 2 months prior to baseline. Or estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73m2, or protein:creatinine ratio \>2.0 g/g.