Efficacy and Safety of Mycophenolate Mofetil in subjectswithSjogren's Syndrome

Inclusion Criteria: 1. Diagnosis of primary Sjogren's syndrome based on the 2002 American-European Consensus criteria 2. Aged 20 to 75 years 3. Stable doses of oral corticosteroids(≦5mg/d) for at least 4 weeks before enrollment 4. Intolerance or inadequate response to hydroxychloroquine and (pilocarpine or cevimeline), defined as less than 50mm on at least 2 of VAS including: 1. global assessment : 0mm (very bad) to 100mm (very good) 2. pain: 0mm (very bad) to 100mm (very good) 3. fatigue: 0mm (very bad) to 100mm (very good) 4. xerostomia: 0mm (very bad) to 100mm (very good) 5. Adequate contraception for patients of childbearing potential Exclusion Criteria: 1. Receiving biologics during the 6 previous months or any other immunosuppressant (methotrexate, cyclophosphamide, cyclosporine, azathioprine, mycophenolate mofetil (MMF), mycophenolate sodium, leflunomide, penicillamine) during the previous month 2. Any one of laboratory abnormalities: 1. Serum creatinine ≥2 mg/dl 2. aspartate aminotransferase (AST) or alanine transaminase (ALT) more than 1.5 x upper normal range of the laboratory 3. Leukopenia (WBC\<4000/μl) 4. Hb ≤ 9 g/dl (5.6 mmol/l) for males and 8.5 g/dl (5.3 mmol/l) for females 5. Neutrophil less than 1.5 x 109/l 6. Platelet count less than 150 x 109/l 3. History of other autoimmune diseases 4. Use topical cyclosporine eyedrops, antihistamine, anticholinergic, antidepressant, or antipsychotic drug with possible effects on ocular dryness or oral dryness within 1 month 5. Pregnant or lactating women 6. Previous or current malignancies adequately controlled less than 5 years, hepatitis B, hepatitis C, HIV infection, tuberculosis, or diabetes 7. Subjects with serious infections requiring hospitalization within the last 12 months 8. Subjects with herpes zoster or cytomegalovirus that resolved less than 2 months before enrollment 9. Subjects who have received any live vaccines within 3 months 10. Underlying cardiac, pulmonary, metabolic, renal, hepatic, gastrointestinal, haematological or neurological conditions, chronic or latent infectious diseases or immune deficiency which places the patient at an unacceptable risk for participation in the study 11. History of recurring or chronic infections or underlying conditions which may further predispose patients to serious infection 12. Subjects who are impaired, incapacitated, or incapable of completing study-related assessments 13. History of allergy to mycophenolate sodium 14. Nausea, vomiting, diarrhea within 1 week before enrollment 15. History of psychosis, seizure, retinopathy 16. Infection 2 weeks before enrollment 17. Heart rate \< 60/min at rest