Mepolizumab ( 美泊珠单抗 )

Mepolizumab is a humanized IL-5 antagonist monoclonal antibody produced by recombinant DNA technology in Chinese hamster ovary cells.It has a molecular weight of approximately 149 kDa.It was approved by the FDA in November,2015 for the treatment of asthma under the brand name Nucala (marketed by GlaxoSmithKline).Mepolizumab has been investigated in the treatment of severe nasal polyposis,among numerous other conditions.Mepolizumab is an interleukin-5 antagonist (IgG1 kappa).IL-5 is the major cytokine responsible for the growth and differentiation, recruitment, activation,and survival of eosinophils.Mepolizumab binds to IL-5 with a dissociation constant of 100 pM,inhibiting the bioactivity of IL-5 by blocking its binding to the alpha chain of the IL-5 receptor complex expressed on the eosinophil cell surface.Inflammation is an important component in the pathogenesis of asthma. Multiple cell types (e.g., mast cells,eosinophils, neutrophils,macrophages, lymphocytes) and mediators (e.g., histamine, eicosanoids, leukotrienes, cytokines) are involved in inflammation.Mepolizumab,by inhibiting IL-5 signaling, reduces the production and survival of eosinophils;however,the mechanism of mepolizumab action in asthma has not been definitively established.