A Study of the Safety and Efficacy of Two Different Regimens of Mipomersen in Patients With Familial Hypercholesterolemia and Inadequately Controlled Low-Density Lipoprotein Cholesterol

Primary objective:

Determine whether mipomersen (ISIS 301012) significantly reduces atherogenic lipid levels in patients with severe heterozygous familial hypercholesterolemia (severe HeFH), defined as low-density lipoprotein cholesterol (LDL-C) levels ≥200 mg/dL plus the presence of coronary heart disease (CHD)/risk equivalents or LDL-C levels ≥300 mg/dL regardless of the presence of CHD/risk equivalents (referred to as Cohort 1) compared to placebo. Two different mipomersen dosing regimens will be studied: subcutaneous (SC) mipomersen 200 mg once weekly versus placebo, and SC mipomersen 70 mg thrice weekly versus placebo.

Secondary Objectives:

* Determine whether there are qualitative differences between the safety profiles of the 2 dosing regimens and placebo in Cohort 1, patients with HeFH with LDL-C levels ≥160 mg/dL and \<200 mg/dL plus the presence of CHD/risk equivalents (referred to as Cohort 2), and the overall study population
* Determine whether there are qualitative differences between the tolerability of the 2 dosing regimens and placebo in Cohort 1, Cohort 2, and the overall study population
* Further characterize the pharmacokinetics (PK) of the 2 dosing regimens in Cohort 1, Cohort 2, and the overall study population
* Determine whether the 2 mipomersen dosing regimens significantly reduce atherogenic lipid levels in Cohort 2 compared to placebo
* Obtain additional data regarding ongoing safety and efficacy of mipomersen in patients with FH and inadequately controlled LDL-C who complete the primary efficacy assessment visit (PET) in the Blinded Treatment Period and continue treatment in Open-Label Continuation Period

The study consisted of a Screening period of up to 4 weeks, Blinded Treatment Phase of 60 weeks, Open-Label Continuation Period of 26 weeks, and Post-Treatment Phase of 24 weeks.

Study Design, masking - Study treatment was blinded (double-blinded) through the Primary Efficacy Assessment Visit in the Blinded Treatment Period. Study treatment was open-label in the Open-Label Continuation Period.

Eligibility Criteria:
Inclusion Criteria:

* Diagnosis of severe hypercholesterolemia (LDL-C ≥300 mg/dL (7.77 mmol/L) or LDL-C ≥200 mg/dL (5.18 mmol/L) with documented coronary heart disease (CHD) or CHD risk equivalents, or diagnosis of Heterozygous Familial Hypercholesterolemia and LDL-C ≥160 mg/dL (4.14 mmol/L) and \<200 mg/dL (5.18 mmol/L))
* On stable, maximally tolerated, statin therapy for at least 12 weeks or if statin intolerant, on at least 1 medication from another class of hypolipidemic agents (i.e., bile acid sequestrants, niacin/nicotinic acid, cholesterol absorption inhibitors, fibrates).
* On stable, low fat diet for 12 weeks
* Body mass index (BMI) ≤40 kg/m2 and stable weight for \> 6 weeks

Exclusion Criteria:

* Significant health problems in the recent past including heart attack, stroke, coronary syndrome, unstable angina, heart failure, significant arrhythmia, hypertension, blood disorders, liver disease, cancer, digestive disorders, Type I diabetes, or uncontrolled Type II diabetes
* Apheresis within 3 months prior to Screening or expected to start apheresis during the treatment phase