Measure Liver Fat Content After ISIS 301012 (Mipomersen) Administration

This was a randomized, double-blind, placebo-controlled study to measure the effect of treatment with mipomersen on liver triglyceride (TG) content in patients with varying degrees of hyperlipidemia and risk for hepatic steatosis.

The original study design included 4 cohorts (Cohorts A through D). Subsequent protocol amendments added 3 cohorts (Cohorts E, F, and G) to the study, truncated the enrollment of Cohort D, and eliminated Cohorts B and C. The study consisted of up to a 3-week screening period; a 4-week (Cohorts A and D), 13-week (Cohort E), or 52-week (Cohort G) treatment period; and a 20-week post-treatment follow-up period. Cohort F was an observational cohort, and therefore, was not treated with study drug. Patients in this cohort underwent a 15-week Magnetic resonance spectroscopy (MRS) and ultrasound evaluation period.

The study cohorts are:

Cohort A: Healthy volunteers with LDL-C <140 mg/dL (3.6 mmol/L), serum TG <200 mg/dL (2.3 mmol/L), hemoglobin A1c (HbA1c) <6.0%, and hepatic TG content <5% (as measured by MRS at screening). Patients were randomized to mipomersen 200 mg or placebo and treated for 4 weeks.

Cohorts B+C were eliminated in a protocol amendment prior to enrolling any patients and are not discussed further.

Cohort D: In an amendment to the protocol, Cohort D was closed to enrollment. One patient had already been enrolled in the study prior to the amendment. The patient enrolled in this cohort had impaired fasting glucose (defined as fasting blood glucose >6 mmol/L and <7 mmol/L) and mixed dyslipidemia (LDL-C <215 mg/dL [5.6 mmol/L] and serum TG >200 mg/dL [2.3 mmol/L]). The patient was treated with mipomersen 200 mg for 4 weeks.

Cohort E: Patients with uncomplicated heterozygous familial hypercholesterolemia (HeFH) (Alanine aminotransferase (ALT) ≤1.5 * upper limit of normal Upper limit of normal (ULN), no evidence of insulin resistance or metabolic syndrome, and hepatic TG content <5% by MRS at screening). Patients were to remain on their baseline statin ± ezetimibe regimen but were to wash out from other lipid-lowering agents (e.g., fenofibrate, non-dietary omega-3 fatty acids, and niacin) at least 8 weeks prior to the MRS at screening. Patients were randomized to either mipomersen 200 mg or placebo for 13 weeks.

Cohort F: Patients with familial hypobetalipoproteinemia (FHBL) (a documented APOB gene mutation that results in the expression of a truncated form of apo B). Patients in this cohort were evaluated by MRS, ultrasound, and laboratory tests; however, they were not treated with mipomersen or placebo.

Cohort G: Patients with well-controlled type 2 diabetes mellitus (HbA1c ≤8.0%), hypercholesterolemia (LDL-C >100 mg/dL (2.59 mmol/L), and normal serum TG levels (≤200 mg/dL [2.26 mmol/L]). Patients were to have been on a stable dose of antidiabetic and lipid-lowering medications >3 months prior to screening and were expected to remain stable for the duration of the study. Patients were randomized to either mipomersen 200 mg or placebo for 26 weeks, followed by 26 additional weeks of mipomersen 200 mg. Recruiting difficulties caused this cohort to close early.