Nedosiran (Rivfloza), a once-monthly RNA interference (RNAi) injection, gained FDA approval for certain patients with primary hyperoxaluria type 1 (PH1), drugmaker Novo Nordisk announced Monday.

The lactate dehydrogenase A-directed small interfering RNA is indicated to lower Urinary Oxalate levels in patients ages 9 years and older with relatively preserved kidney function, defined as an eGFR ≥30 mL/min/1.73 m².

The rare genetic disease causes overproduction of Oxalate by the liver. PH1 is the most common of the PH subtypes, accounting for about 80% of all patients, mainly affecting the kidneys. This is also the most severe of the three PH subtypes.

“RNA interference is a proven treatment approach for individuals with PH1. With the approval of Rivfloza, we now have a novel treatment that lowers Oxalate Production safely and effectively,” said David Goldfarb, MD, of NYU Langone Medical Center in New York City, in the company statement. “Using the GalXC RNAi platform, Rivfloza targets the liver-specific lactate dehydrogenase enzyme, which is the final step of oxalate production in PH1.”

Approval was based on results from the phase II PHYOX2 clinical trial and phase III PHYOX3 extension study. From days 90 to 180, participants treated with nedosiran achieved a reduction in 24-hour urinary oxalate excretion, with percent change from baseline in 24-hour urinary oxalate measured by area under the curve (AUC) analysis.

The least squares mean difference in the AUC of 24-hour urinary oxalate was -3,486 (95% CI -5,025 to -1,947) with nedosiran compared with 1,490 (95% CI 781-3,761) with placebo — a between-group difference of 4,976 (95% CI 2,803-7,149, P

The most common adverse event occurring in 20% or more of patients was injection site reaction, including reddening, pain, bruising, rash, or dimple. There are no contraindications to use, according to the drug label. Nedosiran is approved at three dosages (80 mg, 128 mg, and 160 mg), with dosing based on age and body weight.

The first drug approved for this indication was Alnylam Pharmaceuticals’s lumasiran (Oxlumo) back in 2020.