ARB-272572 (ARB272572, Compound A) is a potent small-molecule PD-L1 inhibitor, inhibits PD-1/PD-L1 with HTRF IC50 of 0.4 nM.
ARB-272572 induces PD-L1 dimerization and internalization, exhibits similar upregulation of CMV responses as αPD-L1 antibodies in CMV recall assay with IC50 of 3.0 nM.
ARB-272572 is a potent in vitro inhibitor of PD-1/PD-L1 cell signaling through induction of PD-L1 protein homo-interactions, which can lead to immunostimulatory activity in human primary cells.
ARB-272572 inhibits tumor growth of PD-1/PD-L1 humanized mice implanted with MC38 cells expressing humanized PD-L1 (10 mg/kg orally).
ARB-272572 enhance HBV-specific immune responses not only activated Ag-specific T cells (IFN-γ production), but also directly stimulated Ag-specific B cells to proliferate and differentiate into Ab-secreting cells.
