Study to Assess the Safety and Efficacy of ISIS 301012 (Mipomersen) in Homozygous Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder of lipoprotein metabolism characterized by markedly elevated low density lipoprotein (LDL), premature onset of atherosclerosis and development of xanthomata. Patients with homozygous familial hypercholesterolemia (HoFH) have a severe disease that presents in childhood with total cholesterol typically in the 650 to 1000 mg/dL range.

This was a randomized, double-blind, placebo-controlled study, which consisted of a 4-week screening period, 26 weeks of treatment, and a 24-week post- treatment follow-up period (with the exception of patients who enrolled in the open-label extension study, Study 301012-CS6; NCT00694109). Eligible patients were randomized in a 2:1 ratio to receive 200 mg mipomersen or matching volume placebo subcutaneous (SC) injections weekly. Patients who weighed <50 kg received a lower dose of 160 mg mipomersen or matching volume of placebo SC injections weekly. Patients were to have been on a stable (>=12 weeks) regimen of allowed lipid-lowering therapies at screening, and were required to remain on the same dose and regimen throughout the study.

Patients returned to the study center for clinical evaluation every other week during the first 4 weeks of treatment, once every 4 to 5 weeks for the remainder of the treatment period, and monthly during the post-treatment evaluation (follow-up) period. The primary endpoint assessment was at Week 28. Following treatment and Week 28 evaluations, eligible patients who tolerated the study drug could elect to enroll in the open-label extension study (Study 301012-CS6; NCT00694109). Patients who did not participate in the open-label extension study were required to return to the study center for clinical evaluation at least twice during the post-treatment follow-up period, including an end-of-study termination visit at the end of this 24-week period.