A Multicenter, Double-Blind, Randomized, Placebo-Controlled Study to Evaluate the Lipid-Altering Efficacy, Safety, and Tolerability of SCH 58235 When Added to Ongoing Therapy With an HMG-CoA Reductase Inhibitor (Statin) in Patients With Primary Hypercholesterolemia, Known Coronary Heart Disease, or Multiple Cardiovascular Risk Factors

This is a study to evaluate the lipid-altering efficacy, safety, and tolerability of ezetimibe when added to ongoing therapy with an 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitor (statin) in participants with primary hypercholesterolemia, multiple cardiovascular risk factors, or known coronary heart disease (CHD) or CHD-equivalent disease. The statin and dose in use by the participant at screening will be maintained at the same dose for the 8-week treatment phase of the study. Following the treatment, there will be a 6-week cholesterol reversibility phase to determine the rebound effect on cholesterol after ezetimibe is discontinued, but the participant is still on their statin therapy. The primary hypothesis is that the addition of ezetimibe 10 mg/day to ongoing statin monotherapy will result in a further reduction in low-density lipoprotein-cholesterol (LDL-C) compared with placebo.

The protocol was amended to include an extension for participants who complete the base study. The extension will evaluate the safety and tolerability of concomitant treatment of simvastatin with ezetimibe10 mg/day over a 1-year period. All participants in the extension will be converted from current statin to an equivalent dose of simvastatin for 6 weeks. Participants then will be randomly assigned to receive simvastatin coadministered with either with Ezetimibe 10 mg daily or matching placebo for the reminder of study.