Patient case: 24-year-old female with familial hypercholesterolemia; genetic feature: PCSK9

Clinical trial: Safety and Efficacy Study of ISIS 301012 (Mipomersen) Administration in High Risk Statin Intolerant Subjects

Summary: The purpose of this study is to determine safety and efficacy of mipomersen (ISIS 301012) in the reduction of total cholesterol, low density lipoprotein cholesterol (LDL-C), and apolipoprotein B (apoB) in high risk subjects intolerant to statins.

Detailed description: In humans, apoB is the principal apolipoprotein of the atherogenic lipoproteins, comprising very low-density lipoprotein (VLDL), intermediate density lipoprotein (IDL) and low density lipoprotein (LDL). ApoB messenger ribonucleic acid (mRNA) is abundantly present in the liver. Within the endoplasmatic reticulum, apoB requires lipidation by microsomal triglyceride transfer protein, which allows apoB to be incorporated in the VLDL particle within the lumen of the endoplasmatic reticulum. Non-lipidated apoB is readily degraded via ubiquitination. Notably, apoB within the VLDL particle is obligatory for hepatic secretion of VLDL. ApoB remains present within the VLDL-metabolism pathway, from secretion to clearance of the end product LDL by the liver LDL receptor. As a consequence, apoB reliably reflects the total burden of atherogenic lipoproteins. Thus, apoB carries strong prognostic value for cardiovascular events, which exceeds the predictive value of LDL-C. Conversely, decreased levels of apoB (e.g. in familial hypobetalipoproteinemia) have been associated with reduced levels of atherosclerosis. These genetic observations have prompted interest in pharmacologic inhibition of apoB synthesis.
  Mipomersen (ISIS 301012) is an antisense drug targeted to human apoB, the principal apolipoprotein of LDL and its metabolic precursor, VLDL. Mipomersen (ISIS 301012) is complementary to the coding region of the mRNA for apoB, binding by Watson and Crick base pairing. The hybridization (binding) of mipomersen (ISIS 301012) to the cognate mRNA results in Ribonuclease (RNase) H-mediated degradation of the cognate mRNA, thus inhibiting translation of the apoB protein.
  This was a randomized, double-blind, placebo-controlled Phase 2 study to assess the safety and efficacy of mipomersen administration in high-risk statin-intolerant patients with hypercholesterolemia. This study consisted of a ≤3-week screening period, 26 weeks of treatment, and a 24-week post-treatment follow-up period.
  Eligible patients were randomized in a 2:1 ratio to receive mipomersen 200 mg or matching volume placebo subcutaneous (SC) injections weekly.
  Following the screening visit, eligible patients returned to the study center for clinical evaluation every week for study drug administration and assessments.

Eligibility: Inclusion Criteria:
  -  Diagnosis of statin intolerance
  -  Diagnosis of Coronary Artery Disease (CAD)
  -  Diagnosis of hypercholesterolemia
  -  Stable weight for > 6 weeks
  Exclusion Criteria:
  -  Significant health problems in the recent past (≤24 weeks) including heart attack, heart surgery, heart failure, uncontrolled hypothyroidism, blood disorders, digestive problems, disease of central nervous system, cancer, liver or renal disease

Relevance to patient case: not relevant