XB628

XB628 is a first-in-class bispecific antibody designed as a natural killer (NK) cell engager for cancer immunotherapy. It simultaneously targets NK group 2 member A (NKG2A), an inhibitory receptor on NK cells, and programmed death-ligand 1 (PD-L1), an immune checkpoint protein expressed on tumor cells. By dual targeting these molecules, XB628 aims to enhance anti-tumor immune responses by activating NK cells and blocking tumor-mediated immune evasion. The drug was developed through a collaboration between Exelixis and Invenra, utilizing Invenra's B-Body® platform for multispecific antibodies with optimized biophysical properties. Preclinical studies have demonstrated that XB628 is effective in promoting tumor cell killing both in vitro and in vivo, supporting its advancement into clinical development for advanced or metastatic solid tumors[1][3][4][5][6][10].