A new first-of-its-kind therapy is launching onto the U.S. marketplace with a costly price tag — and value-based deals with a handful of health insurers that should help with patient access while assuring them that they are paying for value.

On Aug. 10, the FDA approved Alnylam Pharmaceuticals, Inc.’s Onpattro (patisiran) for the treatment of adults with polyneuropathy caused by hereditary transthyretin-mediated (hATTR) amyloidosis. It is the first drug the agency has approved for this condition, as well as the first in a new class of drugs called small interfering ribonucleic acid (siRNA) treatment.

Dosing for Onpattro, an intravenous infusion administered over about 80 minutes, is weight-based. With a cost per vial of $9,500, the average annual list price is $450,000, based on an average of 2.7 vials administered an average of 17.5 times per year. But after taking into account mandatory government discounts, Alnylam estimates that the average annual net price will be $345,000.

On Aug. 13, Orsini Healthcare Specialty Pharmacy and US Bioservices, a specialty pharmacy that’s part of AmerisourceBergen Corp., said that Alnylam had selected them to distribute Onpattro.

Barry Greene, Alnylam president, says that the company has been “negotiating value-based agreements with several insurers to ensure that payment for the drug is based on the ability of Onpattro to potentially halt or in some patients reverse neuropathy impairment.” Alnylam has “agreed in principle” with Harvard Pilgrim Health Care, Inc. “and other major insurance carriers” on the structure of such arrangements.

Besides Harvard Pilgrim, Aetna Inc. would appear to be another company inking a value-based deal for Onpattro, as Jim Clement, executive director of value based care and supply chain management at Aetna Pharmacy Management, said he was “looking forward to being a part of this Alnylam initiative.”