Onpattro first RNAi hATTR drug approved by FDA, but will carry hefty price tag

The US Food and Drug Administration has approved Onpattro (patisiran) lipid complex injection, a first-of-its-kind RNA interference (RNAi) therapeutic, for the treatment of the polyneuropathy of hereditary transthyretin-mediated (hATTR) amyloidosis in adults, says the drug’s developer, Alnylam Pharmaceuticals (Nasdaq: ALNY).

The FDA approved the drug for a narrower group of patients than investors had hoped, which could limit the early uptake of the drug. Alnylam said that fewer than 3,000 people in the USA have been diagnosed, with the news sending the firm’s shares tumbling 7.6% to $90.00 after markets closed on Friday following the announcement.

Onpattro is the first and only FDA-approved treatment for this indication. hATTR amyloidosis is a rare, inherited, rapidly progressive and life-threatening disease with a constellation of manifestations. In addition to polyneuropathy, hATTR amyloidosis can lead to other significant disabilities including decreased ambulation with the loss of the ability to walk unaided, a reduced quality of life, and a decline in cardiac functioning.