&NA;Roxifiban (DMP 754, MK 0853, XJ 754) is the lead compound from a series of isoxazolines, non-peptide glycoprotein IIb/IIIa antagonists that are orally active. Roxifiban is the monoacetate prodrug and its active free acid form is XV 459. Roxifiban is an analogue of XR 300, with increased antiplatelet activity and duration of action. It has demonstrated potent and selective antiplatelet activityin vitroand is under phase II clinical development with DuPont Pharmaceuticals (formerly DuPont Merck) in the US for the treatment of thrombotic disorders. A study in aspirin treated patients undergoing coronary angioplasty is underway.