Patisiran (ONPATTRO™) is a double-stranded small interfering RNA encapsulated in a lipid nanoparticle for delivery to hepatocytes. By specifically binding to a genetically conserved sequence in the 3' untranslated region of mutant and wild-type transthyretin (TTR) messenger RNA, patisiran causes its degradation (via RNA interference) and subsequently a reduction in serum TTR protein levels and tissue TTR protein deposits. Patisiran has been developed by Alnylam Pharmaceuticals; it was recently approved in the USA for the treatment of the polyneuropathy of hereditary TTR-mediated amyloidosis (hATTR) in adults and subsequently approved in the EU for the treatment of hATTR in adults with stage 1 or 2 polyneuropathy. The recommended dosage, administered as a single intravenous infusion over approximately 80 min, is 0.3 mg/kg once every 3 weeks for patients weighing < 100 kg and 30 mg once every 3 weeks for patients weighing ≥ 100 kg. This article summarizes the milestones in the development of patisiran leading to these approvals.