xmab808

XmAb808 is a tumor-selective, co-stimulatory bispecific antibody developed using Xencor’s XmAb 2+1 format. It is designed to bind both the broadly expressed tumor antigen B7-H3 (CD276) and the T-cell co-stimulatory receptor CD28. By engaging both targets simultaneously, XmAb808 provides conditional CD28-mediated co-stimulation of T cells only in the presence of B7-H3-expressing tumor cells. This approach aims to enhance anti-tumor immune responses while minimizing off-tumor activation and associated toxicities seen with previous CD28-targeted therapies. The molecule incorporates Xencor’s engineered Fc domain for improved half-life and manufacturability. XmAb808 is being investigated primarily for advanced solid tumors and has been studied in combination with pembrolizumab[1][2][4][5][9].

Other names

anti-B7-H3/CD28 bispecific antibody XmAb808