Effects of Glycoprotein IIb/IIIa Antagonists: Anti Platelet Aggregation and Beyond

BACKGROUND: The use of inhibitors of glycoprotein IIb/IIIa (GPIIb/IIIa) has provided dramatic results in terms of the prevention of acute stent thrombosis and a reduction in major adverse coronary events in patients subjected to percutaneous coronary intervention. GPIIb/IIIa or alpha IIb beta 3 is a member of the beta 3 subfamily of integrins, which also includes alpha IIb beta 3. GPIIb/IIIa functions as a receptor for fibrinogen and several adhesion proteins sharing an arginine-glycine-aspartic acid (RGD) sequence. GPIIb/IIIa antagonists, through blockade of the receptor, prevent platelet aggregation. Among the three GPIIb/IIIa antagonists used in therapy, abciximab is an anti-beta 3 monoclonal antibody, while tirofiban and eptifibatide mimic the binding sequence of the fibrinogen ligand. Although antiplatelet aggregation represents the central function of GPIIb/IIIa inhibitors, further actions have been documented for these compounds. Objective: The aim of the present article is to review the structures and functions of GPIIb/IIIa antagonists and to highlight the clinical outcomes and results of randomized trials with these compounds. Hypotheses on the unexplored potential of GPIIb/IIIa antagonists will be put forward. Conclusion: GPIIb/IIIa inhibitors were developed to prevent platelet aggregation, however, these compounds can exert further biological functions, both platelet- and non-platelet-related. Large-scale studies comparing the efficacy and safety of GPIIb/IIIa antagonists are lacking. More insights into the functions of these compounds may lead to generation of novel small molecules able to antagonize platelet aggregation while promoting vascular repair.