XmAb657

XmAb657 is a rationally designed bispecific T-cell engager antibody targeting CD19 and CD3, developed for the treatment of autoimmune diseases. It is engineered to deplete B cells by engaging both the B-lymphocyte antigen CD19 on B cells and the T cell surface glycoprotein CD3 on T cells, thereby redirecting cytotoxic T cells to eliminate pathogenic B cells. The molecule features an extended half-life, which may allow for less frequent dosing compared to other agents in its class. Preclinical studies have demonstrated deep depletion of B cells (>99.98%) in non-human primates across peripheral blood and bone marrow compartments[1][2][9]. XmAb657 is being developed by Xencor as a potential therapy for patients with autoimmune diseases who may benefit from targeted B-cell depletion[1][2][9].