Efficacy of Lapaquistat Acetate Alone or Combined With Simvastatin in Subjects With Hypercholesterolemia

Elevated plasma cholesterol (hypercholesterolemia) and various other plasma lipid imbalances (dyslipidemias) are major risk factors for coronary heart disease. Patients with hypercholesterolemia have elevated low-density lipoprotein cholesterol, which leads to atherosclerotic deposition of cholesterol in the arterial walls. As identified by the National Cholesterol Education Program Adult Treatment Panel III, lowering the low-density lipoprotein cholesterol plasma concentration effectively reduces cardiovascular morbidity and mortality and is essential for the prevention and management of coronary heart disease. Currently, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) are the first-line monotherapies prescribed to reduce low-density lipoprotein cholesterol, after diet and therapeutic lifestyle change. However, low doses of statins often fail to produce the ATP III-recommended levels of low-density lipoprotein cholesterol reduction, making it necessary to increase the dose or add an additional treatment. Dose increases of statins in turn may result in decreased tolerability and potential safety concerns which contribute to the high discontinuation rates of statins and their prescription at low, and often ineffective, doses. The purpose of this study is to determine whether administration of lapaquistat acetate co-administered with simvastatin will be more efficacious in lowering low-density lipoprotein cholesterol, compared to lapaquistat or simvastatin alone. Total participation time in this study is anticipated to be 19 weeks.