Thrombosis triggered by severe arterial lesions is inhibited by oral administration of a glycoprotein IIb/IIIa antagonist.

Platelet aggregation and thrombosis play an important role in the onset of acute coronary events. Regardless of the stimulus for activation, platelet thrombus formation is ultimately regulated through the IIb/IIIa receptor complex. The effects of oral administration of xemilofiban, a non-peptide mimetic of the RGDF sequence of the IIb/IIIa receptor complex, on thrombus formation were evaluated in a canine model. Xemilofiban significantly reduced platelet deposition on severely damaged arterial wall. Platelet deposition was reduced at both low (13 +/- 1 from 56 +/- 18 x 10(6) platelets cm-2; P < 0.05) and high (23 +/- 2 from 111 +/- 21 x 10(6) platelets cm-2; P < 0.01) shear rates. Platelet deposition was reduced to a monolayer as seen by electron microscopy (platelet-vessel wall interaction). Therefore, the availability of an orally active IIb/IIIa antagonist for chronic use may have significant value in preventing thrombus formation in those clinical situations associated with severe arterial injury, such as atherosclerotic plaque disruption.