- Alnylam Pharmaceuticals on Monday won Food and Drug Administration approval for its third medicine, an injection called Oxlumo that's used to treat a rare genetic disorder.
- Oxlumo, until recently known as lumasiran, is the first approved treatment for patients with a condition known as primary hyperoxaluria type 1, or PH1, which can cause kidney failure and become life threatening. The FDA action comes days after regulators cleared the therapy in Europe.
- Like Alnylam's other two marketed drugs, Oxlumo is expensive. The average annual list price is $493,000, though Alnylam expects that rebates and discounts will bring the average, effective price closer to $380,000.
In little more than two years, Alnylam has shepherded three medicines to market, the products of groundbreaking science that "silences" genes to halt disease. The first of these so-called RNA interference drugs, Onpattro, cleared the FDA in August 2018. The Cambridge, Massachusetts-based biotech then won approval for the second, Givlaari, in November 2019.
Oxlumo works by breaking down messenger RNA to inhibit the production of a tissue-damaging chemical called oxalate. Patients who suffer from PH1 produce too much oxalate, which can lead to kidney stones and organ damage throughout the body. Some PH1 patients with kidney failure are forced to undergo dialysis almost daily for as many as 10 to 12 hours, Alnylam said.
Research has showed that Oxlumo can significantly lower a patient's levels of oxalate, compared with a placebo. Alnylam is continuing to study the medicine's effects, including in patients on dialysis.
PH1 is quite rare. Alnylam estimates that between 1,000 and 1,700 people in the U.S. and Europe — those who have a confirmed diagnosis but haven't received a liver transplant — would be eligible for its treatment. The company expects to begin shipments by the end of the year in the U.S.
Alnylam said it's already working with payers to set up "value-based agreements" for the sale of Oxlumo, and has concluded initial talks with Express Scripts, Harvard Pilgrim and Highmark to pursue the agreements.
Costs for each patient will vary over time because the medicine, which was approved for both adults and children, is dosed by weight. Rebates will be available if the average number of vials used by a plan member tops a particular threshold, giving payers more predictability, Alnylam said.
As part of Oxlumo's approval, Alnylam gets what's known as a priority review voucher, a tool that can be used for a speedy FDA review of a future product. The program is designed to encourage drugmakers to develop medicines for rare pediatric diseases.