Study of YK012 in Moderate to Severe Systemic Lupus Erythematosus

Prior treatment

• Known allergy to monoclonal antibodies or exogenous human immunoglobulins, or hypersensitivity to the investigational drug or any of its components
• Received any anti-CD19/CD20 therapy or any B-cell depleting agents within 6 months prior to enrollment, or B-cell stimulatory factor inhibitors within 3 months or 5 half-lives prior to enrollment
• Received TNF inhibitors, interleukin receptor blockers, other small molecules or biologics within 3 months or 5 half-lives prior to enrollment
• Received intravenous immunoglobulins or plasmapheresis within 3 months prior to enrollment
• Used traditional Chinese medicines/herbal preparations for SLE treatment containing within 2 weeks prior to enrollment
• Received live or attenuated vaccines within 1 month prior to enrollment
• Clinically significant cardiovascular/cerebrovascular diseases within 6 months prior to screening
• History of non-SLE conditions requiring oral/intravenous/intramuscular/subcutaneous corticosteroid therapy (\>2 weeks) within 6 months prior to enrollment
• Lupus nephritis requiring protocol-prohibited medications as assessed by the investigator
• Uncontrolled lupus crisis within 8 weeks prior to screening
• Had major surgery within 4 weeks prior to enrollment or planned during study;
• Participation in other interventional clinical trials within 4 weeks prior to enrollment

Other illness

• Has other autoimmune diseases, inflammatory joint diseases, or skin disorders (other than SLE) that may interfere with disease activity assessment
• History of malignancy within 5 years before screening, except for cured cases with no recurrence for at least 5 years, such as basal cell or squamous cell skin cancer, cervical carcinoma in situ, ductal carcinoma in situ of breast, or papillary thyroid cancer
• Presence of poorly controlled hypertension at screening
• Active tuberculosis at screening or untreated latent tuberculosis
• History of solid organ or bone marrow transplantation
• Presence of active infections
• History of central nervous system (CNS) disorders
• Presence of clinically unstable or uncontrolled medical conditions at screening
• Presence of active viral infections (e.g., hepatitis B, hepatitis C, HIV, or active syphilis)
• Other conditions deemed by investigators to preclude study participation.

Lab values

• Presence of clinically significant abnormal laboratory test results

Other

• Presence of QTcF interval prolongation on electrocardiogram (ECG)
• Pregnant or lactating women, or individuals with pregnancy plans during the study and within a specified period after treatment who are unwilling to use effective contraception

• Aged 18 to 75 years (inclusive) at screening, regardless of sex
• Meet the 2019 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for SLE, with a confirmed SLE diagnosis for at least 24 weeks at screening
• Positive for anti-dsDNA antibody and/or antinuclear antibody (ANA) and/or anti-Smith antibody at screening, as determined using the local laboratory's reference ranges at the study site
• Medium to high disease activity at screening, defined as: Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score ≥7
• Receiving stable background therapy at screening
• Capable of understanding and voluntarily participating in this clinical trial, having provided written informed consent, and able to comply with scheduled visits, treatments, examinations, and other study procedures.