Inotersen: First Global Approval

Ionis Pharmaceuticals and Akcea Therapeutics have developed inotersen (Tegsedi™), an antisense oligonucleotide inhibitor of mutant and wild-type human transthyretin (TTR), for the treatment of hereditary transthyretin amyloidosis (hATTR). Mutation of the TTR gene results in accumulation of TTR protein fragments as amyloid deposits throughout the organs in patients with hATTR, including the peripheral nervous system and the heart. Treatment with inotersen, which selectively binds to TTR mRNA, prevents the synthesis of TTR protein in the liver, thus reducing further amyloid deposition throughout the body. Subcutaneous administration of inotersen significantly reduced neurological progression and improved health-related quality of life in patients with hATTR and polyneuropathy in a phase III trial. Based on these results, inotersen was recently approved in the EU for the treatment of stage 1 or 2 polyneuropathy in adult patients with hATTR and is under evaluation in the USA and Canada for a similar indication. This article summarizes the milestones in the development of inotersen leading to this first approval.