Monoclonal Antibodies in the Treatment of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by B cell hyperactivity and defective T-cell function, with production of high titer autoantibodies. In the recent years, conceptual advances and the introduction of new therapies are yielding improvements in the management of this disease. In recent years, clinical studies have been undertaken with selected monoclonal antibodies (mAbs) in the treatment of SLE. The important role of B cells in the pathogenesis of autoimmune disorders has provided a strong rationale to target B cells in SLE. Selective therapeutic depletion of B-cells became possible with the availability of the anti-CD20 antibody rituximab and anti-CD22 antibody epratuzumab. Several clinical studies confirm high activity of rituximab in SLE patients especially with lupus nephritis and neuropsychiatric involvement. Recently, several new mAbs reacting with CD20 have been developed. New mAbs directed against CD20 include fully human mAb ofatumumab (HuMax CD20), IMMU-106 (hA20) which has a > 90% humanized framework and GA-101, a novel third-generation fully humanized and optimized mAb. These agents are highly cytotoxic against B-cell lymphoid cells. Proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and iterleukin-6 (IL-6) play an important role in propagating the inflammatory process responsible for tissue damage. Blocking of these cytokines by mAbs can be also a successful therapy for patients with SLE. Finally, mAb eculizumab that specifically inhibits terminal complement activation has been recently developed and investigated in the phase I single dose study in SLE. In this review, new mAbs, potentially useful in SLE are presented.