EP4 receptor antagonist 7 (Compound 14) is an antagonist of the prostaglandin E2 (PGE2) receptor subtype EP4, with an IC50 of 1.1 nM. This compound inhibits PGE2-induced β-arrestin recruitment in HEK293 cells with an IC50 of 0.9 nM. In RAW 264.7 macrophages, it reduces the expression of PGE2-induced IL-4, macrophage mannose receptor 1 (Mrc1), chitinase-like protein 3 (Chil3), chemokine (C-X-C motif) ligand 1 (Cxcl1), triggering receptor expressed on myeloid cells 2 (Trem2), and arginase 1 (Arg1) mRNA. In the CT26 mouse colon cancer model, EP4 receptor antagonist 7, combined with an anti-PD-1 antibody, inhibits tumor growth and enhances CD8+ T cell infiltration into the tumor.