Study of ISIS 301012 (Mipomersen) in Heterozygous Familial Hypercholesterolemia Subjects on Lipid Lowering Therapy

Inclusion Criteria: * Weight ≥ 50 kg * Diagnosis of Heterozygous Familial Hypercholesterolemia. * Females must be non-pregnant and non-lactating. * On stable lipid lowering therapy for at least 4 weeks. * Lipid levels meet the pre-specified criteria. Exclusion Criteria: * Subject had heart problems in the prior 6 months. * Subject has elevated ALT, AST, or CPK. * History of renal disease, liver disease, or malignancy. * Use of oral anticoagulants, unless the dose has been stable for 4 weeks * Have any other conditions, which in the opinion of the Investigator would make the subject unsuitable for enrollment, or could interfere with the subject participating in or completing the study.