This study is a multicenter, randomized, double-blind, placebo-controlled clinical trial. The primary objectives of this study are to examine the safety, tolerability, and efficacy of intravenous MCC-135 in limiting final infarct size, as measured by single photon emission computed tomography (SPECT), in patients who require percutaneous coronary intervention (PCI) for a first-documented ST-segment elevation acute myocardial infarction (AMI).