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 ant…