Structure−Activity Relationship Studies Leading to the Identification of (2E)-3-[l-[(2,4-Dichlorophenyl)methyl]-5-fluoro-3-methyl-lH-indol-7-yl]-N-[(4,5-dichloro-2-thienyl)sulfonyl]-2-propenamide (DG-041), a Potent and Selective Prostanoid EP3 Receptor Antagonist, as a Novel Antiplatelet Agent That Does Not Prolong Bleeding

The EP3 receptor on the platelet mediates prostaglandin E2 potentiation of thrombogenic coagonists including collagen and adenosine diphosphate (ADP). A pharmacophore driven approach led to the identification of diverse peri-substituted heterocycles as potent and selective EP3 receptor antagonists. A simultaneous chemical optimization and druglike assessment of prioritized molecules converged on a lead compound 50 (DG-041) that displayed favorable in vitro and functional activities as an inhibitor of human platelet aggregation. This agent is currently in human clinical trials for the treatment of atherothrombosis.