This study is designed to explore the efficacy and safety of upadacitinib and clarify the influence on immune function in the treatment of primary Sjögren's Syndrome.
Male or female >18 years of age at screening visits
Participants with diagnosis of pSS according to the 2016 ACR/EULAR criteria
Participants have an ESSDAI score ≥ 5
Participants must be on a stable dose of prednisone (≤10mg/day), antimalarials or equivalent, and cholinergic stimulants prior to Baseline.
Pregnant or breastfeeding female.
Diagnosis of other autoimmune disease, or other sicca syndrome.