Alnylam Pharmaceuticals has secured FDA approval for Oxlumo (lumasiran), marking a significant breakthrough as the first treatment for primary hyperoxaluria type 1 (PH1), an ultra-rare and potentially fatal genetic disorder. This approval, which follows European Union authorization last week, represents the third RNA interference (RNAi) therapeutic from Alnylam's pipeline to reach the market.
PH1 affects patients by causing excessive production of oxalate, a substance that combines with calcium to form kidney stones and deposits. As the disease progresses, kidney function deteriorates, potentially leading to kidney failure requiring dialysis. When kidney function worsens, oxalate accumulation can damage multiple organs including the heart, bones, and eyes.
Mechanism of Action and Clinical Evidence
Oxlumo employs Alnylam's gene-silencing RNAi technology, specifically targeting hydroxyacid oxidase 1 mRNA that codes for the enzyme glycolate oxidase. By preventing the production of this enzyme, the drug reduces oxalate synthesis at its source.
The approval follows successful clinical trial results from the phase 3 ILLUMINATE-A study, which demonstrated that Oxlumo achieved its primary endpoint of significantly reducing urinary oxalate excretion compared to placebo. The drug also met all six secondary endpoints, including bringing urinary oxalate levels to near-normal ranges in a significant proportion of patients.
"PH1 is a devastating disease that is extremely challenging to diagnose, often taking around six years before physicians correctly identify it," said John Maraganore, Alnylam's Chief Executive Officer. "With Oxlumo, we now have a treatment option that addresses the underlying cause of the disease rather than just managing symptoms."
Market Position and Competition
The approval gives Alnylam a clear advantage in this niche market. The nearest competitor, Dicerna Pharmaceuticals, is developing DCR-PHXC for both PH1 and PH2, but this candidate remains further back in clinical development with pivotal trial results expected later this year.
Another company, OxThera, is pursuing a different approach with Oxabact, a therapy based on freeze-dried bacteria that break down oxalate in the gut. OxThera's phase 3 trial results are anticipated in mid-2021.
Economic Implications
While Alnylam has not yet announced pricing for Oxlumo, industry analysts expect it to command a premium price given the ultra-rare nature of PH1. The company's previous rare disease treatments provide some indication: Givlaari, approved last year for acute hepatic porphyria, costs $575,000 per year before discounts in the US, while Onpattro for hereditary ATTR amyloidosis is priced at approximately $450,000 annually.
Financial analysts have projected peak sales estimates for Oxlumo ranging from $400 million to $600 million, with Alnylam's own projections sitting at approximately $500 million.
Expanding RNAi Portfolio
Oxlumo's approval strengthens Alnylam's position as the leader in commercializing RNAi therapeutics. The company's first product, Onpattro, was approved in 2018 for polyneuropathy in hereditary ATTR amyloidosis, followed by Givlaari in 2019 for acute hepatic porphyria.
Despite these successes, Alnylam is not yet profitable. The company reported increased losses in Q3 2020, reaching more than $253 million compared to $208.5 million in the same period last year. However, the company anticipates growing revenue streams from its expanding product portfolio and partnership payments.
Alnylam also stands to benefit from its relationship with Novartis, which acquired The Medicines Company and its rights to inclisiran, another RNAi therapeutic developed with Alnylam's technology. Inclisiran, currently under regulatory review for cholesterol management, is widely predicted to achieve blockbuster status if approved.
Patient Impact
For patients with PH1, Oxlumo represents a groundbreaking advance in treatment options. Prior to this approval, management strategies were limited to hyperhydration, crystallization inhibitors, and ultimately kidney and/or liver transplantation in severe cases.
"The approval of Oxlumo addresses a significant unmet need for patients with PH1," noted a clinical investigator involved in the trials. "By targeting the disease at its biochemical roots, we can now offer patients a therapy that may prevent the devastating progression of this condition and potentially avoid the need for invasive procedures like dialysis and organ transplantation."
As Alnylam works to establish pricing agreements with healthcare systems globally, the company has stated it will pursue separate pricing deals with each European member state to ensure patient access as quickly as possible.
