Bapotulimab (BAY-1905254) is a human/mouse/monkey cross-reactive monoclonal antibody that targets and inhibits ILDR2 (immunoglobulin-like domain containing receptor 2), blocking its immunosuppressive activity for cancer immunotherapy. Bapotulimab promotes T-cell activation in mice, enhancing antigen-specific T-cell proliferation and cytotoxicity.

Bapotulimab inhibits the immunosuppressive effect of ILDR2 on T cell activation. This agent exhibits cross-reactivity between humans and mice, attributed to a 98% sequence identity in the extracellular domain between human and murine orthologs of ILDR2 [1]. Bapotulimab (BAY-1905254; at concentrations of 5, 25, 100, or 500 ng/mL) enhances T cell activation and promotes the proliferation of antigen-specific T cells in vitro [1].

Bapotulimab (BAY-1905254; 10 mg/kg; intraperitoneal injection; administered on days 1 and 4) demonstrated a significant increase in antigen-specific T-cell proliferation and cytotoxicity [1].