AN OVERVIEW OF THE RESULTS OF CLINICAL-TRIALS WITH GLYCOPROTEIN IIB IIIA INHIBITORS/

The era of platelet glycoprotein (CP) IIb/IIIa receptor inhibition in cardiology was inaugurated in 1994 with the publication of the Evaluat ion of 7E3 for the Prevention of Ischemic Complications (EPIC) trial r esults. EPIC demonstrated that the GP IIb/IIIa blocker abciximab, admi nistered as a bolus and 12-hour infusion, afforded protection against ischemic complications in high-risk patients undergoing angioplasty an d atherectomy, including those with unstable angina or evolving myocar dial infarction (MI). A significant reduction in the incidence of deat h, acute MI, or revascularization was apparent at 30 days and also sus tained at 6-month and 3-year follow-up. The subsequent Evaluation in P TCA 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 ben efits in low-risk patients as well. The EPILOG trial also proved that any excess bleeding risk associated with potent antiplatelet therapy c ould be brought down to placebo levels through the use of a low-dose, weight-adjusted heparin regimen, early vascular sheath removal, and el imination of routine postprocedural heparinization. The potential for an advantage of GP IIb/lIIa blockade in patients with refractory unsta ble angina/non-q-wave MI was demonstrated in the c7E3 Fab Antiplatelet Therapy in Unstable Refractory Angina (CAPTURE) trial, which showed t hat a 24-hour preprocedural abciximab infusion effectively stabilized these patients, thereby enhancing the safety of intervention and reduc ing the 30-day incidence of ischemic events. A similar pattern of bene fit has emerged from clinical trials of such other GP IIb/IIIa inhibit ors as eptifibatide, lamifiban, and tirofiban. Trials are currently un derway to clarify the benefits of GP IIb/IIIa blockers in patients und ergoing stenting and as an adjunct to thrombolytic therapy or primary angioplasty in patients with acute MI (ST-segment elevation).