Novel treatments for systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that is associated with the production of autoantibodies, and with considerable morbidity and mortality. There has been much interest in developing more specific therapies for this disease, which is currently managed with immunosuppressive drugs, predominantly corticosteroids, azathioprine, methotrexate and cyclophosphamide, in combination with hydroxychloroquine. Mycophenolate mofetil has been demonstrated to be as efficacious as cyclophosphamide in patients with lupus nephritis, and is being used increasingly in the clinic despite not being licensed for this indication. Novel methods of reducing autoantibody formation in SLE include the use of mAbs that modulate and/or deplete B-cells (anti-CD22 and anti-CD20 antibodies, respectively), or that interfere with the stimulatory effects of the soluble factor B-lymphocyte stimulator (anti-BLys antibodies). Alternative approaches include the use of atacicept (Merck Serono), a transmembrane activator and calcium modulator ligand interactor (TACI)-Ig fusion protein, which inhibits B-cell stimulation by binding to BLys and a profileration-inducing ligand (APRIL), or toleragens such as abetimus. Blocking costimulatory molecule interactions, such as the CD40-CD40 ligand interaction with mAbs and the CD28-B7 interaction with a soluble cytotoxic T-lymphocyte antigen 4 (CTLA-4)-IgG1 construct (abatacept), has also been attempted as a therapeutic strategy for SLE. The most promising strategy for a new drug for SLE is belimumab (Human Genome Sciences/GlaxoSmithKline), an anti-BLys antibody, as two phase III clinical trials with this drug recently met their primary endpoints. In this review, these novel approaches to the treatment of SLE, including the potential of targeting cytokine pathways involved in autoimmunity, are discussed.