The Future of Targeted Treatment of Primary Sjögren's Syndrome: A Focus on Extra-Glandular Pathology

Abstract

Primary Sjögren's syndrome (pSS) is a chronic, systemic autoimmune disease defined as exocrine gland hypofunction resulting in dry eyes and dry mouth. Recent interest in biological therapies for pSS has been garnered, however achieving FDA-approval has been challenging due to the numerous complications in the trials. Current literature lacks insight and a molecular target-based approach to the development of biological therapies. This review focuses on novel research in newly defined drug targets and latest clinical trials for pSS treatment. A literature search was conducted on ClinicalTrials.gov using the search term “Primary Sjögren's syndrome”. Articles published between 2000 and 2021 in English language were included. Our findings revealed the potential targets for pSS treatment in clinical trials and the most recent advances in understand-ing of molecular mechanisms underlying the pathogenesis of pSS. A prominent gap in current trials is overlooking the treatment of extraglandular symptoms such as fatigue, depression and anxiety which pervade most patients with pSS. Based on dryness and these symptom-directed therapies, emerging biological agents targeting inflammatory cytokines, signal pathways and immune reaction have been studied and proved the efficacy and safety. Novel therapies may complement existing non-pharmacological methods of alleviating symptoms of pSS. Better grad-ing systems adding extraglandular symptoms to gauge disease activity and severity should be created. The future of pSS therapies may lie in gene therapy, stem cell and tissue engineering ther-apy.