A Trial to Evaluate the Efficacy and Safety of Sibeprenlimab Administered Subcutaneously in Participants With Sjögren's

Key Inclusion Criteria: * Diagnosed with Sjögren's disease. * ESSDAI score (which measures disease activity) must be 5 or higher. * Salivary flow rate must be at least 0.05 mL/min. * Serum IgG level must be higher than 900 mg/dL. * Must be able to communicate well with the investigator and agree to follow the trial requirements. * Participants can continue certain medications (hydroxychloroquine, methotrexate, leflunomide, or azathioprine) if they have been on a stable dose for at least 30 days. * Corticosteroid dose must be stable and no more than 10 mg/day for at least 30 days. * Test positive for anti-Ro52 and/or anti-Ro60 antibodies. Key Exclusion Criteria: * Another active autoimmune rheumatic disease. * Prior use of B-cell depleting therapy or prohibited immunosuppressants. * Significant comorbidities including uncontrolled type 2 diabetes, malignancy, and chronic and/or acute infections. * Suicidal ideation or behavior based on the Patient Health Questionnaire-9 (PHQ-9).