Mipomersen sodium (Kynamro™) (henceforth mipomersen) is a second-generation antisense oligonucleotide inhibitor of apolipoprotein B-100, which is the main structural component of atherogenic lipid particles. Mipomersen is administered via subcutaneous injection and is indicated as adjunctive treatment for homozygous familial hypercholesterolaemia (HoFH). The drug was developed by Isis Pharmaceuticals, which now collaborates with Genzyme Corporation for on-going development and product marketing. Multinational phase III trials of mipomersen as adjunctive therapy were completed in patients with HoFH, severe FH, heterozygous FH (HeFH) with coronary artery disease (CAD), and in those with hypercholesterolaemia at high risk of CAD. Mipomersen 200 mg once weekly has been approved in the USA as an adjunct to lipid-lowering medications and diet in HoFH patients and is undergoing regulatory review in the EU for the same indication. Genzyme is also conducting a multinational phase III, open-label extension study to evaluate long-term treatment in HoFH and HeFH patients, as well as a multinational trial to evaluate a three-times-per-week mipomersen regimen in patients with severe FH. This article summarises the milestones in the development of once-weekly, subcutaneous mipomersen leading to this first approval.