The effects of pactimibe versus placebo on the progression of atherosclerosis in the carotid arteries will be assessed using standard ultrasound techniques.

Inclusion Criteria:

• Confirmed diagnosis of heterozygous familial hypercholesterolemia
• Ambulatory male (40 to 75 years, inclusive) or female (45 to 75 years, inclusive) subjects
• Calculated LDL-C level greater than or equal to 100 mg/dL (or 2.5 mmol/L) and triglycerides less than 500 mg/dL (5.65 mmol/L) while on usual and stable lipid-lowering therapy

Exclusion Criteria:

• Breast feeding or lactating women
• Previous organ transplantation
• High-grade stenosis (>75%) or the occlusion of any segment of either carotid artery
• History of carotid endarterectomy, or insertion of carotid artery stent or are scheduled to have either of these procedures