Inclusion Criteria:  Primary Sjogren's syndrome (pSS) diagnosed according to the American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) 2016 Criteria. Lymphocyte focus score (local lymphocytic infiltrates) >= 1 in sublabial salivary gland specimen. Subjects with sublabial salivary gland biopsy obtained 3 months prior to Screening and meeting this criterion will be eligible without a biopsy at Screening. Subjects without a sublabial salivary gland biopsy within 3 months of Screening will obtain a biopsy for a lymphocyte focus score at Screening. EULAR Sjogren's Syndrome Disease Activity Index (ESSDAI) >= 5 at Screening. EULAR Sjogren's Syndrome Patient Reported Index (ESSPRI) >= 6 at Screening.  Exclusion Criteria:  History of clinically significant drug or alcohol abuse within the last 6 months. History of an allergic reaction or significant sensitivity to constituents of the study drug (and its excipients), the ingredients of Chinese hamster ovary cells and/or other products in the same class.