BACKGROUND: Percutaneous coronary intervention (PCI) is a highly effective therapy for acute ST-elevation myocardial infarction. Adjunctive therapy with platelet glycoprotein (GP) IIb/IIIa inhibitor can result in increased vessel patency and improved outcomes in ST-elevation myocardial infarction patients undergoing PCI. The investigation of novel dosing and delivery strategies of this therapy may help to further improve outcomes. METHODS: IC-Clearly is a randomized, open-label, multicenter trial, with the purpose of evaluating the effectiveness of an intracoronary bolus dose of abciximab delivered using the ClearWay RX catheter vs. an intravenous bolus of abciximab for ST-elevation myocardial infarction with angiographically visible thrombus (thrombus grade ≥ 2). A total of 150 patients will be randomized 1: 1 to treatment of the culprit artery with intracoronary abciximab (75 patients) or intravenous abciximab (75 patients) in addition to a maintenance infusion regimen of abciximab administered intravenously for 12 h after PCI. The number of patients included in this study is based on the estimation of sample size needed to identify a statistically significant difference in the primary endpoints between the two groups. The primary endpoint chosen to evaluate this hypothesis is infarct size assessed by cardiac magnetic resonance. Clinical outcomes will be assessed for each patient through hospital discharge and at 30-day follow-up. CONCLUSION: The purpose of this study is to evaluate whether an intracoronary bolus of abciximab delivered with the ClearWay RX catheter prior to the 12 h post-PCI intravenous infusion regimen of abciximab will result in significant additional clot resolution in vivo and improved myocardial perfusion when compared with an intravenous bolus of abciximab on top of the 12 h post-PCI intravenous infusion regimen of abciximab as per standard practice. The primary endpoint chosen to evaluate this hypothesis is infarct size as assessed by cardiac magnetic resonance. © 2010 Italian Federation of Cardiology.