Coronary artery disease is the leading cause of death in the United States, accounting for almost 500,000 deaths each year. Studies have confirmed that myocardial infarction is related to an occlusive coronary thrombus in up to 80 percent of patients. First and second-generation thrombolytic agents (including streptokinase and rt-PA) have been successfully used to restore myocardial blood flow where thrombus has occluded an infarct-related coronary artery. However, further clinical investigation was necessary to determine the most suitable thrombolytic agent dose and method of administration, the risk of subsequent reocclusion, restenosis, and/or myocardial infarction, the need for additional therapies, and the likelihood of benefit or hemorrhagic complications.