Prostaglandin E2 evokes distinct responses through four different 'E prostanoid' (EP) receptors. EP2 is a G protein-coupled receptor that has diverse roles, including those in cancer, inflammation, and neuroprotection. TG6-129 is an antagonist of the EP2 receptor, suppressing PGE2-induced elevation of cAMP in cells expressing EP2 with an IC50 value of 1.6 µM. It is without effect on EP4, DP1, IP, and β2-adrenergic receptors. TG6-129 reduces the expression of COX-2, IL-1β, IL-12, IL-23, IL-6, and TNF-α induced by the EP2-selective agonist butaprost in P388D1 macrophages. It has low cell cytotoxicity (CC50 = 326 µM), prolonged plasma half-life, and does not cross the blood-brain barrier.