ACT-453859

ACT-453859 is a potent and selective antagonist of the chemoattractant receptor-homologous molecule expressed on T helper-2 cells (CRTH2), also known as the prostaglandin D2 receptor 2 (DP2). It was developed as a small molecule oral therapy targeting inflammatory and cardiovascular disorders. The drug works by blocking CRTH2, a G-protein-coupled receptor for prostaglandin D2, which plays a key role in mediating inflammatory responses through recruitment and activation of Th2 cells, eosinophils, basophils, and group 2 innate lymphoid cells. ACT-453859 was initially developed by Actelion Pharmaceuticals; following acquisition, development continued under Janssen Pharmaceuticals (a subsidiary of Johnson & Johnson). Clinical development reached phase 1 trials in healthy volunteers for cardiovascular disorders but has not advanced further or received regulatory approval[1][3][4][7].