(Adds details on drug pricing, analyst comment; updates shares)
By Trisha Roy
Nov 20 (Reuters) - Alnylam Pharmaceuticals Inc priced its gene silencing drug to treat patients with a rare genetic disorder that can cause severe pain at $575,000 per year after receiving an early U.S. approval on Wednesday.
The drug, Givlaari, uses a Nobel Prize-winning mechanism known as RNA interference to target and "silence" specific genetic material and is the second such drug to be approved http://bit.ly/37oqz9Z by the U.S. Food and Drug Administration.
The injection, which is dosed based on patient weight, will be available after discounts at $442,000 per year and is approved for acute hepatic porphyria (AHP), a rare disorder that can lead to severe pain and paralysis, respiratory failure and seizures.
"Givlaari will be an entirely new therapy for a poorly treated rare disease patient population," said Oppenheimer analyst Leland Gershell. He expected peak sales of $560 million and $47 million next year based on its price tag.
Alnylam's other treatment, Onpattro, last year became the first approved treatment that uses gene silencing technology. (https://reut.rs/2XyFFFe)
The company said it reached a "value-based agreement" in principle with Harvard Pilgrim Healthcare to cover the drug and was in talks with other health insurers.
Under such agreement, Alnylam would be paid based on the ability of the drug to deliver outcomes in the real world setting comparable to those seen in clinical trials.
The population of AHP patients with diagnosed, active disease in the United States and Europe is estimated to be about 3,000, but the time to diagnosis can be as long as 15 years due to the broad, non-specific range of symptoms, Alnylam said.
The company said Givlaari will be subjected to an additional feature that will trigger rebates or discounts to insurers if the number of diagnosed patients they cover exceeds current estimates.
Shares of the Massachusetts-based drugmaker were up 10% at $108.35.
The FDA, which was due to decide on the drug by Feb. 4, said treatment options for the disorder have been limited, providing only partial relief to the patients before the approval.
Bernstein, which had modeled Givlaari at a net price in the range of $400,000-$500,000 per patient per year, said the approval was broadly expected.
(Reporting by Trisha Roy and Manas Mishra in Bengaluru; Editing by Sriraj Kalluvila and Arun Koyyur)