An overview of the results of clinical trials with glycoprotein IIb/IIIa inhibitors.

The era of platelet glycoprotein (GP) IIb/IIIa receptor inhibition in cardiology was inaugurated in 1994 with the publication of the Evaluation of 7E3 for the Prevention of Ischemic Complications (EPIC) trial results. EPIC demonstrated that the GP IIb/IIIa blocker abciximab, administered as a bolus and 12-hour infusion, afforded protection against ischemic complications in high-risk patients undergoing angioplasty and atherectomy, including those with unstable angina or evolving myocardial infarction (MI). A significant reduction in the incidence of death, acute MI, or revascularization was apparent at 30 days and also sustained at 6-month and 3-year follow-up. The subsequent Evaluation in PTCA to Improve Long-Term Outcome with Abciximab GP IIb/IIIa Blockade (EPILOG) study extended these findings to the full spectrum of coronary intervention patients, confirming that abciximab provided similar benefits in low-risk patients as well. The EPILOG trial also proved that any excess bleeding risk associated with potent antiplatelet therapy could be brought down to placebo levels through the use of a low-dose, weight-adjusted heparin regimen, early vascular sheath removal, and elimination of routine postprocedural heparinization. The potential for an advantage of GP IIb/IIIa blockade in patients with refractory unstable angina/non-Q-wave MI was demonstrated in the c7E3 Fab Antiplatelet Therapy in Unstable Refractory Angina (CAPTURE) trial, which showed that a 24-hour preprocedural abciximab infusion effectively stabilized these patients, thereby enhancing the safety of intervention and reducing the 30-day incidence of ischemic events. A similar pattern of benefit has emerged from clinical trials of such other GP IIb/IIIa inhibitors as eptifibatide, lamifiban, and tirofiban. Trials are currently underway to clarify the benefits of GP IIb/IIIa blockers in patients undergoing stenting and as an adjunct to thrombolytic therapy or primary angioplasty in patients with acute MI (ST-segment elevation).