FDA Approves First-of-its-Kind RNA Therapy

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The new drug, Onpattro (patisiran), by Alnylam Pharmaceuticals, is in a new class of drugs called small interfering ribonucleic acid (siRNA) treatment.

FDA has approved Alnylam Pharmaceuticals’ Onpattro (patisiran) infusion, a first-of-its-kind RNA-based therapy for treating peripheral nerve disease (polyneuropathy) caused by hereditary transthyretin-mediated amyloidosis (hATTR) in adult patients, the agency announced in an Aug. 10, 2018 press release. The treatment is in a new class of drugs called small interfering ribonucleic acid (siRNA) treatment. Polyneuropathy caused by hATTR is a rare, debilitating, and often fatal genetic disease characterized by the buildup of abnormal amyloid protein in peripheral nerves, the heart, and other organs.

“This approval is part of a broader wave of advances that allows 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. In this case, the effects of the disease cause a degeneration of the nerves, which can manifest in pain, weakness, and loss of mobility,” said FDA Commissioner Scott Gottlieb, MD, in the agency’s press release. “New technologies like RNA inhibitors that alter the genetic drivers of a disease, have the potential to transform medicine, so we can better confront and even cure debilitating illnesses. We’re committed to advancing scientific principles that enable the efficient development and review of safe, effective and groundbreaking treatments that have the potential to change patients’ lives.”

RNA acts as a messenger that controls protein synthesis by carrying DNA instructions throughout cells. RNA interference is a process that occurs naturally within cells to block the expression of certain genes. Since its discovery in 1998, scientists have used RNA interference as a tool to investigate gene function and its involvement in health and disease.

siRNAs work by silencing a portion of RNA involved in causing a disease. More specifically, Onpattro encases siRNA into a lipid nanoparticle that delivers the drug directly into the liver in an infusion treatment to alter or halt the production of disease-causing proteins.


Onpattro is designed to interfere with RNA production of an abnormal form of the protein transthyretin (TTR), which can reduce the accumulation of amyloid deposits in peripheral nerves, improving symptoms and helping patients better manage the condition.

FDA granted fast track, priority review, breakthrough therapy, and orphan drug designations to the Onpattro application. On July 27, the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) granted a positive opinion for patisiran, the active ingredient in Onpattro, for treating hereditary transthyretin-mediated amyloidosis in adults with stage 1 or stage 2 polyneuropathy. The drug is under accelerated assessment by EMA. The European Commission is expected to review the CHMP recommendation in September to make a final decision on marketing authorization, which will be applicable to all 28 European Union member states, plus Iceland, Liechtenstein, and Norway. Regulatory filings in other markets, including Japan, are also planned to start in mid-2018.

Source: FDA and Alnylam Pharmaceuticals