Do differences in pharmacology of platelet GP IIb/IIIa inhibitors affect clinical outcomes?

Comparison of outcomes in clinical trials of platelet glycoprotein (GP) IIb /IIIa antagonists suggests that abciximab treatment is associated with grea ter absolute and relative reductions in coronary event rates in patients un dergoing percutaneous coronary intervention than is treatment with availabl e small-molecule antagonists. It has been speculated that pharmacological d ifferences between abciximab and the small-molecule antagonists may be refl ected in clinical performance. Pharmacological differences between abcixima b and small-molecule inhibitors include (1) large compared with small molec ular size, (2) long platelet-bound/short plasma circulation time for abcixi mab compared with short platelet-bound/extended plasma circulation time for the small molecules, and (3) binding abciximab to GP IIb/IIIa and alpha(v) beta(3) integrins with equal affinity and weaker binding to leukocyte Mac-1 compared with avid binding to GP IIb/IIIa only. In addition to a prolonged effect of abciximab on platelet aggregation, the clinical implications of these differences may include beneficial effects of abciximab on dissolving existing thrombi (dethrombosis) and on post-injury vessel wall passivation , as well as restenotic, anti-inflammatory and anticoagulation benefits.