Efficacy and safety data of belimumab in patients with systemic lupus erythematosus.

Belimumab is a human genome derived monoclonal antibody with specificity for BLyS (B lymphocyte stimulator, or B-cell activating factor [BAFF]), a cytokine that promotes the survival and maturation of B cells into antibody-secreting plasmablasts. Recent phase III clinical trials with belimumab in patients with active systemic lupus erythematosus (SLE) have been completed and achieved primary efficacy endpoints employing validated disease activity measures (SLEDAI and BILAG) as well as additional secondary endpoints related to disease flares and sparing of corticosteroid use. Significant decreases in numbers of activated B cells as well as levels of autoantibodies are observed during treatment with belimumab. The majority of observed clinical improvements are observed in musculoskeletal, mucocutaneous, and serologic domains of disease activity; the potential effects on more severe neurologic or renal domains of disease are not known. Treatment with belimumab is well tolerated and has not been associated with significant toxicity.