Progress in the field of GPIIb/IIIa antagonists

Platelet aggregation plays an important role in pathological situations such as myocardial infarction, unstable angina, peripheral artery disease, and stroke. Thus, pharmacological agents that specifically inhibit platelet aggregation are of great interest in the treatment and prevention of these cardiovascular diseases. Since binding of activated glycoprotein IIb/IIIa complex, a platelet surface integrin, to fibrinogen is the final step leading to platelet aggregation regardless of the initial stimulus, many researches have focused on the development of drugs that could antagonize this integrin. Three intravenous glycoprotein IIb/IIIa antagonists are currently marketed for the prevention of myocardial infarction in patients undergoing percutaneous intervention: Abciximab, Eptifibatide and Tirofiban. To further test the clinical efficacy of these agents, oral glycoprotein IIb/IIIa antagonists have been developed but only led to disappointing clinical results. Nevertheless, due to recognized usefulness of oral agents for the prevention and treatment of cardiovascular diseases, a great number of new orally active compounds are under clinical or preclinical evaluation. The aim of this review is to describe the chemical, pharmacological and clinical properties of existing and forthcoming glycoprotein IIb/IIIa antagonists.