A novel modality of BAFF-specific inhibitor AMG623 peptibody reduces B-cell number and improves outcomes in murine models of autoimmune disease

AMG623, also known as A-623, is an antagonist of B-cell activating factor (BAFF). The present study was to evaluate the effects of AMG623 on murine models of autoimmune diseases. AMG623 was generated through phage library. Inhibitory activities of AMG623 against human and murine BAFF were measured by biacore binding and BAFF-mediated B-cell proliferation assay. Pharmacological effects of AMG623 were studied in BALB/c mice, collagen-induced arthritis model (CIA) and in the NZBxNZW F1 lupus model. AMG623 binds to both soluble and cell surface BAFF. AMG623 blocks both human murine BAFF binding to the receptors. Treatment of AMG623 resulted in B-cell number reduction, and improvement of arthritis and lupus development in mice. AMG623 is a novel modality of BAFF antagonist. AMG623 is a potential therapeutic agent for the treatment of SLE, rheumatoid arthritis, and other B-cell-mediated autoimmune diseases.