Idebenone accepted by FDA for priority review for Leber Hereditary Optic Neuropathy

The US Food and Drug Administration (FDA) has granted Priority Review to Chiesi Global Rare Diseases’ idebenone for Leber Hereditary Optic Neuropathy (LHON)

Currently there are no clinically proven therapies for LHON in the US. Idebenone is approved under the name Raxone across EU countries and ex-EU countries, including Israel, South Korea, Serbia, Switzerland, Chile, Bahrain, and Taiwan.

LHON is an inherited mitochondrial disorder that leads to progressive, rapid and severe vision loss caused by genetic mutations that impair the ability of retinal ganglion cells. LHON often begins as a sudden, painless clouding or blurring accompanied by loss of sharpness and color vision. In 75% of cases, the onset of vision loss occurs in one eye first, followed by the other eye within a few weeks or months.

The submission was based on the safety and efficacy data from the phase 3 (RHODOS) and phase 4 (LEROS) studies.

In a phase 3 study (RHODOS), a total of 85 patients with LHON, aged 14 to 65 years, carrying 1 of the 3 primary mitochondrial DNA mutations (m.11778G>A, m.3460G>A, or m.14484T>C), and with disease duration of ≤5 years, were enrolled.

The primary efficacy endpoint was the best recovery of visual acuity (VA), defined as the change from baseline to week 24 in the eye showing the most improvement or least deterioration, measured using Early Treatment Diabetic Retinopathy Study (ETDRS) charts.

A higher proportion of patients in the idebenone group achieved clinically meaningful improvements in visual acuity compared to placebo. These findings were consistent across multiple definitions of response and were further supported by propensity score–weighted analyses.

Nancy J Newman, MD, LeoDelle Jolley chair in ophthalmology at Emory University School of Medicine, commented in a press release from the company, saying, "LHON is a serious condition marked by rapid central vision loss, often beginning in one eye and quickly affecting the other, placing a profound and immediate burden on patients and their loved ones. If approved in the United States, idebenone would represent a meaningful advancement in treatment, offering hope to the LHON community.”

The target action date for the FDA decision is February 28, 2026.

Continue reading about LHON

Recently Alfredo Sadun, MD, PhD, detailed an unexpected outcome from a gene therapy in development for Leber hereditary optic neuropathy (LHON).

References:

1. Idebenone Accepted by FDA for Priority Review for Leber Hereditary Optic Neuropathy (LHON). Published September 22, 2025. Accessed September 22, 2025. https://chiesirarediseases.com/media/20250922-idebenone-accepted-by-fda-for-priority-review-for-leber-hereditary-optic-neuropathy-lhon