Biologic therapies in primary Sjögren's syndrome

Primary Sjögren's Syndrome (PSS) is characterized by dryness of the eyes and mouth due to lymphocytic infiltration of secretory exocrine glands. As well as disabling dryness, patients commonly have fatigue and arthralgia and an associated reduction in quality of life. The condition principally affects adult women and is relatively common--approximately 1:1000 to 1:250 adult women are estimated to have the condition in European/North American studies. Current therapy is principally symptomatic with the use of artificial tears and oral gels, pastilles and sprays. Medications to stimulate residual glandular secretion can be helpful for appropriate individuals. A proportion of patients also develop extraglandular features such as skin vasculitis, or lung, neurological, haematological or other systemic involvement. Conventional general immunosuppressive therapies such as corticosteroids or disease-modifying drugs, have been used in some patients with these clinical features. Biologic therapies specifically directed against molecules involved in disease pathogenesis represent a potentially more effective approach to therapeutic intervention in rheumatic diseases including PSS. The greatest experience in PSS is with rituximab, an anti-B-cell monoclonal antibody already in use for the treatment of B-cell lymphoma and rheumatoid arthritis. A randomised placebo controlled study is currently recruiting in France and a further study is planned in the UK. This review discusses the utility of biologic therapies in PSS, potential challenges for their use, the available data on rituximab and the potential role for other biologic therapies currently in development, or in clinical trials, in other autoimmune conditions.