Genetic testing covered by companies that make treatments for primary hyperoxaluria can help identify cases of this rare condition, which often leads to kidney failure at an early age.
Alnylam Pharmaceuticals, Inc., maker of the lumasiran (Oxlumo), partnered with Prevention Genetics, a unit of Exact Sciences Corporation, to run a testing program free of charge for individuals in the US and Canada. Novo Nordisk, maker of nedosiran (Rivfloza), works with Blueprint Genetics on a similar program.
These programs make it easier for physicians treating patients whose medical histories raise concerns about possible primary hyperoxaluria, said Matthew Breeggemann, MD, a nephrologist and co-medical director of the UCSF’s Kidney Stone Prevention Clinic.
The test kits are mailed to patients. “The patient just swabs the inside of their cheek and then mails it back. And you can get results sometimes within 2, 3 weeks,” he told Medscape Medical News.
Physicians are not required to prescribe the company’s primary hyperoxaluria drug when their patients are tested through its sponsored program, Breeggemann said.
“We take advantage of [these programs] to help our patients like we should, but it doesn’t mean you need to use that company’s drug — the ultimate choice is up to the patient and what is covered by their health insurance plan,” he said.
Excess Oxalate
Primary hyperoxaluria type 1, the most common form, has been estimated to affect about 1 to 3 per 1 million people, but some research suggests it may be more common.
In primary hyperoxaluria, the liver can’t properly regulate the production of oxalate. So the kidneys wind up with excess oxalate, which can combine with calcium to form kidney stones. Over time, oxalate builds up in the body, leading to complications including arrhythmias and cardiac arrest, gangrene, and bone and joint pain and fractures.
One of the potential clues for primary hyperoxaluria is finding kidney stones in children because this is unusual, Breeggemann said. In adults, one signal of this condition would be a finding of high urine oxalate levels on a lab test, Breeggemann noted.
Other signs include frequent formation of kidney stones or having family members with a history of kidney stones. Physicians may also consider genetic testing for primary hyperoxaluria in patients who have kidney stones and unexplained chronic kidney disease, especially in those who don’t have hypertension or diabetes, Breeggemann said.
Limited but Growing Treatment Options
For many years, treatments for primary hyperoxaluria were limited. Patients could try to maintain high fluid intake — intended to maintain brisk flow of diluted urine — and take citrate supplements — intended to increase urinary oxalate solubility. Vitamin B6 may also be prescribed. Some patients would have liver transplants in attempts to address the root cause of their illness. Some would undergo combined or sequential liver and kidney transplants, often preceded by periods of intensive dialysis. This sometimes involved hemodialysis many days of the week and peritoneal dialysis nightly.
But there’s been a marked change recently in the landscape of treatments for primary hyperoxaluria. Alnylam said lumasiran was the first approved pharmaceutical therapy for this condition. US and EU regulators cleared it in 2020.
Lumasiran is a small interfering RNA (siRNA) designed to inhibit the production of oxalate. In 2023, Novo Nordisk received US approval of its siRNA drug, nedosiran, also designed to curb oxalate production.
Several companies have investigational agents in clinical development for the treatment of primary hyperoxaluria as well, Alnylam noted in a regulatory filing. These include Biocodex, Inc., and YolTech Therapeutics.
In addition, Arbor Biotechnologies is working on a drug candidate, ABO-101, that it describes as “a novel gene editing therapeutic” designed to address primary hyperoxaluria type 1.
Breeggemann reported receiving consulting fees from Novo Nordisk and Alnylam Pharmaceuticals.
Kerry Dooley Young is a freelance journalist based in Washington, DC. She has covered medical research and healthcare policy for more than 20 years.