BioPharma, Pharma

FDA approves Alnylam’s siRNA drug Onpattro for rare disorder

The drug is the first approved treatment for the condition, as well as the first siRNA drug to win the agency's approval.

Red seal and imprint "FDA APPROVED" on white surface. FDA - Food and Drug Administration is a federal agency of the United States Department of Health and Human Services.

The Food and Drug Administration has approved the first drug that targets RNA for the treatment of disease.

The agency announced Friday the approval of Cambridge, Massachusetts-based Alnylam Pharmaceuticals’ Onpattro (patisiran), an infused drug for treating peripheral nerve disease caused by hereditary transthyretin-mediated amyloidosis, also known as hATTR, in adults. Onpattro is the first drug approved for polyneuropathy caused by hATTR, and also the first FDA-approved drug belonging to the class known as small interfering RNA, or siRNA treatment.

In an investor presentation, Alnylam said the average annual list price for the drug would be $450,000, or $9,500 per vial, assuming an average 2.7 vials administered 17.5 times per year. However, with mandatory rebates for government institutions, the effective annual price would be $345,000.

Several abnormal genes can cause hereditary amyloidosis, though hATTR is the most common variety, caused by mutations in the transthyretin (TTR) gene, according to the National Organization for Rare Disorders. Hereditary amyloidosis resulting from TTR mutations occurs in approximately 1-in-100,000 Caucasians in the US, but among about 4 percent of African-Americans. The condition is prevalent in Portugal, Sweden, Japan, Ireland, Spain, France, Finland, Germany and Greece, according to NORD. The disease is debilitating and often fatal, resulting from the buildup of abnormal amyloid protein in peripheral nerves, heart and other organs, according to the FDA announcement.

“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,” FDA Commissioner Scott Gottlieb said in a statement.

Generally, siRNA drugs work by silencing a portion of RNA involved in causing a disease. Onpattro encases the siRNA into a lipid nanoparticle to deliver the drug directly to the liver in an infusion in order to alter or halt the production of disease-causing proteins.

Phase III data on Onpattro published July 4 in the New England Journal of Medicine showed that among 225 patients randomized two-to-one to receive the drug or placebo, patients who received the drug saw their neuropathic impairment reduced by about six points after 18 months, compared with an increase of about 28 points for those who received placebo.

The market for RNAi and antisense drugs remains relatively small. According to a report by Grand View Research, its global value stood at $945.8 million in 2016, and it is expected to grow to $1.81 billion by 2025. Other companies in the field include Arrowhead Pharmaceuticals, which is developing RNAi therapeutics for liver disease and envisions itself as the first company to also adapt the technology to diseases outside the liver, as well as Marina Biosciences, Benitec Biopharma and larger players like GlaxoSmithKline and Sanofi.

Photo: Waldemarus, Getty Images

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