– PGN-9856 (PGN9856) is a novel potent, selective prostaglandin EP2 receptor agonist with pKi of > 8.3, shows higi selectivity over EP1 , EP3 , EP4 , DP, FP, IP and TP receptors; displays a potency (pEC50 >8.5) and a maximal response (increase in cAMP) comp