PSI-697 is a quinoline derivative patented by Wyeth, John, and Brother Ltd. as a selectin inhibitor useful for the treatment of acute coronary syndromes. Surface expression of P-selectin on activated platelets induces the formation of platelet-monocyte aggregates and promotes vascular inflammation and thrombosis. In cell-based assays, PSI-697 dose-dependently inhibits the binding of human P-selectin to human P-selectin glycoprotein ligand-1. In preclinical trials, PSI-697, promotes thrombus resolution and decreases inflammation in a baboon model of venous thrombosis. Animals receiving PSI-697 demonstrated significantly increased plasma D-dimer levels versus low-molecular-weight-heparin and control animals six hours post thrombus induction. Unfortunately, in clinical trials, PSI-697 did not inhibit basal or stimulated platelet-monocyte aggregate formation in humans