A Phase 2, Proof of Concept, 52-Week Open Study to Evaluate the Efficacy and Safety of Belimumab (HGS1006, LymphoStat-B™), a Fully Human Monoclonal Anti-BLyS Antibody, in Subjects With Primary Sjögren's Syndrome.

Background and rationale Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by chronic inflammation of salivary and lachrymal glands, frequently accompanied by systemic symptoms. The presence of various autoantibodies such as rheumatoid factor (RF) and anti-SSA/SSB antibodies, as well as hypergammaglobulinemia, reflect B cell hyperactivity. About five percent of patients with SS develop malignant B cell lymphoma, usually of the mucosa-associated lymphoid tissue (MALT) type and most frequently located in the major salivary glands. Currently, there is a lack of evidence-based intervention therapy which may influence SS-related chronic inflammation and lymphoproliferation. B cells are involved in the pathogenesis of SS, and B cell downregulation may lead to a decrease of disease activity. Patients with more residual exocrine gland function, e.g., those with SS of shorter duration, might better benefit from systemic therapy, as reported in a preliminary study on the efficacy of B-cell depletion in SS.This study will examine the effect of the drug Belimumab in patients with SS. Patients aged more than 18 years with SS may be eligible for this study. Candidates will be screened with complete history and physical examination, chest x-rays, and oral and eye examinations.