Efficacy of Clotinab in Acute Myocardial Infarction Trial- ST Elevation Myocardial Infarction

It is well known that platelet-mediated thrombosis is account for the pathophysiology of acute coronary syndrome (ACS) (1,2). In the treatment of ACS, intravenous platelet glycoprotein (GP) IIb/IIIa receptor antagonists for platelet aggregation may reduce the risk of ischemic complications (3-7). Therefore, in the management of ACS, Platelet GP IIb/IIIa receptor inhibitors have been developed as a promising new therapy for the reduction of coronary events and the improvement of clinical outcomes.

Abciximab, one of platelet GP IIb/IIIa receptor blockers, was developed by Coller in 1985 and named as 7E3(8). Abciximab is a chimeric human monoclonal antibody and binds to platelet surface GP IIb/IIIa receptor competitively with adhesive molecules such as fibrinogen and von Willebrand factor, and blocks the final stage of platelet aggregation(9). The effect of Abciximab has been proved in many clinical trials such as the EPIC trial(9), EPILOG trial(10), TARGET(11) etc. The contribution of GP IIb/IIIa inhibition in ACS (Tirofiban) is shown in placebo-controlled trials in which upstream GP IIb/IIIa inhibition was initiated upon admission (12,13). Although these results are encouraging, there are few other data to support the use of upstream GP IIb/IIIa inhibitors. Moreover, according to the GUSTO-IV trial (14), the use of Abciximab was not recommended in the manner of upstream use. To evaluate the role of abciximab in conservatively treated non-ST-elevation ACS patients, the GUSTO-IV study randomized 7800 patients with non-ST-elevation ACS to receive either placebo or an Abciximab bolus (0.25 mg/kg) and 24-hour or 48-hour infusion(0.125 µg/kg/min). However, in fact, a trend was noted for potential harm with the higher abciximab dose. Even subgroup analyses including high-risk troponin-positive patients showed no benefit with either abciximab regimen (9.7% with placebo, 10.2% with 24-hour abciximab, 11.7% with 48-hour abciximab for death or MI at 30 days, P = NS). Because of these results, the majority of patients received abciximab relatively late, at the time of PCI in clinical practices.

However, the ADMIRAL study (3) demonstrated that early administration of abciximab in patients with ST elevation acute myocardial infarction prior to PCI improves clinical outcomes and also no specifically designed randomized study has addressed the issue of early upstream use of GP IIb/IIIa inhibitors in ST elevation acute myocardial infarction who are undergoing PCI, especially in the era of routine pretreatment with 600 mg of clopidogrel. Therefore, the objective of the randomized ECLAT-STEMI study was to assess the hypothesis that the early upstream use of Clotinab is a useful therapy in patients with ST elevation MI undergoing PCI compared to "provisional use", even after pretreatment with a 600-mg loading dose of clopidogrel.

The Clotinab, a product made in ISU ABXIS CO., LTD, was produced by inserting anti- platelet GP IIb/IIIa DNA into Chinese hamster's ovary cell. Since it contains identical active ingredient as ReoPro® on the domestic market, it is expected that the Clotinab has same efficacy to ReoPro® as a platelet GP IIb/IIIa receptor inhibitor. Recently, the Clotinab is shown to be safe and effective in preventing ischemic heart complications for high-risk patients who will undergo PCI.

2. Study Protocol 2-1. Objectives: Randomized, controlled, single blind, multi-center trial To assess the hypothesis that the early upstream use of Clotinab is a useful therapy in patients with ST elevation myocardial infarction undergoing PCI compared to "provisional use", even after pretreatment with a 600-mg loading dose of clopidogrel.