A Blinded Study Conducted at Multiple Centers Evaluating Various Doses of an Investigational Agent (BO-653) Against Placebo, for Safety and Effectiveness in Preventing Post-Angioplasty Blood Vessel Re-Closure (Restenosis) in Stented Vessels.

Major Inclusion Criteria - Others Stipulated within the Protocol The study physician must assure you: * Are at least 18 years of age and have achieved a successful stent placement procedure as defined by ≤ 10% residual stenosis, no residual dissection, TIMI flow \> 3 (complete perfusion), and lack of procedural coronary perforation utilizing an FDA-approved stent, excluding self-expanding, coil, polymer and pharmacologic coated (heparin OK) stents. * Have at least one untreated target lesion in a native coronary artery meeting study entry criteria for diameter (≥ 2.5mm and ≤ 3.5mm), stenosis (≥ 50% and \< 100%), and stent length (≥ 13mm and ≤ 36mm, or total of two stents ≤ 45mm). * Have a documented history of angina pectoris or a positive functional study. * Have no symptoms suggestive of an MI (heart attack) OR have cardiac isoenzymes (CK-MB) within normal range at least 24 hours prior to stent procedure. * Use effective birth control measures, or are unable to conceive children. * Are willing to have a repeat angiogram after 6 months. Major Exclusion Criteria - Others Stipulated within the Protocol The study physician must assure you: * Have not had any coronary intervention within 30 days before, and for an expected 30 days after stenting. * Have not had a cerebrovascular accident or transient ischemic attack within 90 days prior to stent placement. * Have not had stent procedure as a bridge to non-emergency planned bypass. * Have not had a stent placed within the target vessel less than 9 months ago, or less than 5mm from the closest edge of an adjacent lesion. * Do not have an unprotected left main coronary artery disease. * Do not have a left ventricular ejection fraction of \< 30%. * Do not have a target lesion that is located at the ostium (\< 2mm from origin of left anterior descending, right coronary artery, or circumflex vessel), involves a side branch ≥2.0mm diameter, is moderately to severely calcified, or requires use of an atherectomy device. * Have not had a heart transplant. * Do not have a 12-lead ECG with a QTc interval pre- or post stent placement ≥ 460 msec (males), or ≥ 470 msec (females). * Do not have any medical, surgical or psychiatric condition, or be medical unstable as would prevent you from safely participating in the trial. * Do not have clinically relevant bleeding, clotting, or immune disorders or be intolerant of platelet inhibitors and/or anticoagulants. * Are not taking rifampin, carbamazepine, phenobarbitol, cyclophosphamide, ifosfamide, artemisinin, mephenytoin, phenytoin, or cholestyramine. * Have no clinically significant laboratory abnormality (specified: creatinine ≥ 2.2 mg/dl, liver function tests ≥ 2.0 times the upper limit of normal). * Have not participated in any investigational study within past 30 days. * Are not allergic or intolerant to soybean products. * Are not taking vitamin E in excess of 150 I.U. per day and that you are unwilling to stop.