Platelet GPIIb-IIIa blockers

Regardless of the event that stimulates the aggregation of platelets, the r eceptor alpha(IIb)beta(3)-one of a family of adhesion receptors known as in tegrins-has a key role in the process. The past decade has seen the publica tion of 10 phase III (randomised) clinical trials of four members of a new class of antiplatelet drugs, the GPIIb-IIIa blockers, targeted at this impo rtant receptor. Three (abciximab, eptifibatide, and tirofiban) are licensed for human use. 10 other GbIIb-IIIa blockers are in phase II or III human s tudies. In all 10 placebo-controlled trials, done in the clinical settings of percutaneous coronary intervention or acute coronary syndrome in patient s on aspirin, the endpoints favoured the active drug, with a risk reduction for death or non-fatal myocardial infarction of about 21% overall. With at tention to heparin dose the risk of bleeding is not a major concern with th ese agents. The GPIIb-IIIa blockers are taking the clinician and patient ou t of the era of aspirin monotherapy when platelet inhibition is required.