A Study of the Safety and Effectiveness of Efgartigimod in Patients With Primary Sjögren's Syndrome (pSS)

Inclusion Criteria

• Is at least the legal age of consent for clinical trials when signing the informed consent form
• Is capable of providing signed informed consent and complying with protocol requirements
• Agrees to use contraceptive measures consistent with local regulations and measures described in the protocol
• Meets the following criteria at screening: ACR/EULAR 2016 pSS who met criteria ≤7 years before screening; ESSDAI ≥5; Anti-Ro/SS-A positive; Residual salivary flow (UWSF rate >0 and/or SWSF rate >0.10)

Exclusion Criteria

• Known autoimmune disease or any medical condition that, in the investigator's judgment,would interfere with an accurate assessment of clinical symptoms of pSS or puts the participant at undue risk
• History of malignancy unless considered cured by adequate treatment with no evidence of recurrence for ≥3 years before the first administration of IMP.
• Adequately treated participants with the following cancers may be included at any time: Basal cell or squamous cell skin cancer; Carcinoma in situ of the cervix; Carcinoma in situ of the breast; Incidental histological finding of prostate cancer (TNM stage T1a or T1b) Clinically significant uncontrolled active acute or chronic bacterial, viral, or fungal infection
• Positive serum test at screening for an active infection with any of the following: HBV that is indicative of an acute or chronic infection, unless associated with a negative HBsAg or negative HBV DNA test; HCV based on HCV antibody assay unless a negative RNA test is available; HIV based on test results of a CD4 count of 200 cells/mm3 not adequately treated with antiviral therapy
• Clinically significant disease, recent major surgery (within 3 months of screening), or intention to have surgery during the study; or any other medical condition that, in the investigator's opinion, would confound the results of the study or put the participant at undue risk
• Immunoglobulin G (IgG) levels cannot be below a certain threshold ( 4g/L)
• Positive covid test at study start
• Some of the medications such as vaccines with live components or medicines that may be prescribed cannot be taken either shortly before or during this study
• Current participation in another interventional clinical study or previously participation in an efgartigimod clinical study and treatment with ≥1 dose of IMP
• Known hypersensitivity to IMP or 1 of its excipients
• History (within 12 months of screening) of current alcohol, drug, or medication abuse as assessed by the investigator
• Pregnant or lactating state or intention to become pregnant during the study
• Secondary Sjögren's syndrome overlap syndromes where another confirmed autoimmune rheumatic or systemic inflammatory condition is the primary diagnosis
• Chinese traditional medicine with known immunomodulatory action