Title: Advances of treatment with IL-6/IL-6 receptor inhibitors for RA
Abstract:Interleukin (IL)-6 has a wide range of effects on immune cells and contributes to the pathogenesis of autoimmune diseases. In the synovial tissue of rheumatoid arthritis (RA), fibroblast-like synovioc...Interleukin (IL)-6 has a wide range of effects on immune cells and contributes to the pathogenesis of autoimmune diseases. In the synovial tissue of rheumatoid arthritis (RA), fibroblast-like synoviocytes mainly expressed IL-6, which induces production of inflammatory mediators, such as chemokines and adhesion molecules, enhancement of angiogenesis and osteoclastogenesis, and differentiation into Th17 and plasma cell. Therefore, IL-6 signaling was thought to be a therapeutic target for RA. IL-6 is engaged by IL-6 receptor and IL-6 signal transducer/gp130, which leads to the formation of the dimer as a signaling-competent hexamer. Tocilizumab, humanized anti-IL-6 receptor monoclonal antibody (mAb), was launched on 2008 in Japan for RA. It has been shown that tocilizumab is effective for the arthritis and also inhibits bone destruction. Tocilizumab monotherapy, without methotrexate, is also effective. Tocilizumab is now world widely used for RA. Tocilizumab was also used for juvenile idiopathic arthritis and Castleman disease. Moreover, recently tocilizumab has been approved for Takayasu arteritis and giant cell arteritis. Tocilizumab may also be effective for polymyalgia rheumatica. However, treatment of tocilizumab increases frequency of serious infection and sometimes induces neutrocytopenia, thrombocytopenia, and dyslipidemia. Sarilumab, human mAb against anti-IL-6 receptor, was just approved for RA in this year. Sarilumab as well as tocilizumab binds domain 2 of IL-6 receptor. Sarilumab showed similar effects and similar adverse events for RA as tocilizumab. Sirukumab, human anti-IL-6 mAb, also showed efficacy for RA. However, US Food and Drug Administration did not approve it for RA because of slight increase of numbers of dead patients and cardiovascular events. Blockade of IL-6 signaling is effective for RA. It is expected that more IL-6 blocking drugs will be developed.Read More