FDA Accepts Idebenone for Priority Review as First Potential Treatment for LHON

The U.S. Food and Drug Administration (FDA) has accepted idebenone for priority review as a potential treatment for Leber Hereditary Optic Neuropathy (LHON), a rare and vision-threatening mitochondrial disease. Submitted by Chiesi Global Rare Diseases, idebenone may become the first and only FDA-approved therapy for LHON in the United States. The agency has set a target action date of February 28, 2026.

Idebenone Under FDA Review as Potential Treatment for LHON

Currently marketed internationally under the brand name Raxone, idebenone has received regulatory approval in multiple regions. It was first authorized in Switzerland in 2014, followed by the European Union and the United Kingdom in 2015, Israel in 2017, and South Korea and Serbia in 2019. More recent approvals include Chile in 2024, with Bahrain and Taiwan expected to follow in 2025.

If approved in the U.S., idebenone would fill a significant therapeutic gap for LHON, a disease with no currently approved treatments domestically.

Addressing Mitochondrial Dysfunction at Its Source

Idebenone is designed to target mitochondrial dysfunction in retinal ganglion cells, the root cause of vision loss in LHON patients. According to Mitch Goldman, Senior Vice President of R&D at Chiesi Global Rare Diseases:

“Data from our clinical studies and in-market experience suggest that idebenone has a favorable safety profile and the potential to improve vision.”

The FDA’s evaluation is based on a robust dataset, including both randomized controlled trials and real-world observational studies, highlighting idebenone’s ability to stabilize or improve visual function.

Clinical Trial Evidence Supporting FDA Review

Phase 3 – RHODOS Trial

       • Participants: 85 LHON patients aged 14–65 with disease duration ≤5 years

       • Findings: Idebenone led to a greater average gain in visual acuity vs. placebo

       • Clinical Significance: A higher proportion of patients experienced clinically meaningful visual improvements

Phase 4 – LEROS Trial

       • Duration: Assessed visual outcomes at 12 and 24 months

       • Results: Demonstrated sustained improvements in visual acuity

       • Impact: Patients had 3x higher odds of achieving overall clinical benefit compared to natural history controls

Safety Profile of Idebenone

In clinical trials, idebenone was generally well tolerated. The most common adverse reactions, occurring in 3% or more of participants, included mild and reversible increases in liver enzymes and diarrhea.