Alnylam's Onpattro cleared by FDA for adults with hATTR, marking first approval of RNAi therapy

The FDA on Friday authorised Alnylam Pharmaceuticals' Onpattro (patisiran) for the treatment of adults with polyneuropathy due to hereditary transthyretin-mediated amyloidosis (hATTR), marking the first drug approval for this indication in the US. The agency also noted that the therapy is the first small interfering ribonucleic acid (siRNA) treatment to gain clearance. FDA Commissioner Scott Gottlieb said "this approval is part of a broader wave of advances that allow us to treat disease by actually targeting the root cause, enabling us to arrest or reverse a condition, rather than only being able to slow its progression or treat its symptoms." 

Approval of the drug was supported by safety and efficacy data from the Apollo trial of 225 patients with hATTR-induced polyneuropathy. Results of the study, which were unveiled last year, showed that the mean change from baseline in the modified Neuropathy Impairment Score +7 (mNIS+7) was significantly lower among Onpattro-treated patients compared with placebo, while quality of life was also improved in the active treatment group versus placebo. 

Alnylam expects Onpattro to cost about $450 000 annually in the US, although the company said that the net cost of the therapy could be about $345 000 a year after discounts, noting that the price is a "reasonable return for a limited period of time for the investments it made and risks it took." Alnylam also said that it has entered into value-based agreements with Harvard Pilgrim and other insurers regarding coverage for Onpattro. The company further indicated that it is introducing Alnylam Assist, a support services programme that will provide patients with a number of resources including in-house case managers who will assist with verifying insurance benefits and financial support for eligible patients. 

Commenting on the news, Express Scripts chief medical officer Steve Miller said "we applaud Alnylam for taking a responsible approach to pricing and patient access in the rare disease space, an increasingly complicated challenge," continuing "we want to work together toward a common goal of ensuring broad, affordable access to important medicines for rare conditions."

Analysts have forecast sales of $24 million for Onpattro this year, while revenue is expected to surge to more than $1 billion by 2023. Shares in Arbutus Biopharma, which is eligible for royalties on sales of the drug, sank as much as 10 percent on the news as some investors reportedly fear that the approval might be limited to a smaller group of patients.

Alnylam initiated its rolling submission of Onpattro to the FDA last November, with the agency awarding priority review to the filing in February. The FDA granted the drug fast track and breakthrough therapy designation for this indication. 

Last month, the European Medicines Agency's Committee for Medicinal Products for Human Use (CHMP) adopted a positive opinion recommending marketing authorisation of Onpattro for the treatment of hATTR amyloidosis in adults with stage 1 or stage 2 polyneuropathy.

To read more Top Story articles, click here.