The US Food and Drug Administration (FDA) has accepted Chiesi’s Raxone (idebenone) for Priority Review to treat Leber Hereditary Optic Neuropathy (LHON), a rare mitochondrial disorder that causes rapid and severe central vision loss.
The agency has set a target action date of February 28, 2026. If approved, idebenone, already marketed in Europe and other regions under the brand name Raxone, would become the first and only FDA-approved therapy for LHON. The drug is already approved for LHON in multiple countries, including the EU, UK, Israel, South Korea, Switzerland, Chile, Bahrain, and Taiwan.
“LHON changes lives in an instant. This review brings hope of the first-ever approved treatment in the US for LHON, one of the most prevalent mitochondrial diseases,” said Malinda Marsh, Chris Marsh, and Lissa Poincenot, parents of children affected by LHON and co-founders of the LHON Collective.
Raxone’s Clinical Data
Idebenone, a short-chain benzoquinone, is designed to address the mitochondrial dysfunction at the heart of LHON. By preserving and reactivating retinal ganglion cell function, the therapy has demonstrated potential to improve or stabilize vision.
Mitch Goldman, Senior Vice President of R&D at Chiesi Global Rare Diseases, noted that clinical trial data and real-world use indicate idebenone has a favorable safety profile and potential to meaningfully improve outcomes.
The FDA submission included data from two major studies. A Phase 3 RHODOS trial (NCT00747487). Conducted in 85 patients aged 14–65, the study assessed the effect of idebenone on visual acuity. Results showed clinically meaningful improvements in visual acuity among idebenone-treated patients compared to placebo. Post-hoc analyses confirmed that a higher proportion of idebenone patients achieved significant recovery in vision.
A Phase 4 LEROS real-world trial compared idebenone treatment with natural history controls. At 12 months, 42.3% of eyes treated with idebenone achieved clinically relevant benefit versus 20.7% in untreated controls. The benefit was sustained at 24 months. Notably, even patients who began treatment more than a year after onset showed improvement, expanding the drug’s potential applicability.
Common adverse events included mild increases in liver enzymes and diarrhea, but these were generally reversible and did not require discontinuation.
“LHON is a serious condition marked by rapid central vision loss, placing a profound and immediate burden on patients and their loved ones,” Newman said. “Idebenone offers hope to a community that has long had none.”
