Following an unexpected FDA complete response letter (CRL), Alnylam Pharmaceuticals Inc. said it will no longer pursue an expanded indication for Onpattro (patisiran) in the U.S. The RNAi therapeutic was approved in 2018 to treat polyneuropathy of hereditary transthyretin-mediated (ATTR) amyloidosis and seemed well on its way to snagging a second U.S. indication after the FDA’s Cardiovascular and Renal Drugs Advisory Committee voted 9-3 in September that the drug’s benefits outweighed its risks as a treatment for cardiomyopathy of ATTR amyloidosis. The FDA disagreed with the committee, saying in the CRL that patisiran’s clinical meaningfulness had not been established in the proposed indication.
With Alnylam Pharmaceuticals Inc.’s FDA clearance for Amvuttra (vutrisiran) in the rearview mirror, investors are looking ahead to potentially label-widening phase III data related to another, already approved drug: Onpattro (patisiran).
As the company unveiled 18-month results from the phase III study called Helios-A, Alnylam Pharmaceuticals Inc.’s president of R&D, Akshay Vaishnaw, said “new exploratory data with the cardiac endpoints are extremely encouraging.” The study is testing RNAi therapy vutrisiran in polyneuropathy associated with hereditary transthyretin-mediated (hATTR) amyloidosis, where Helios-A met all secondary endpoints measured at 18 months.
