Characteristics of Japanese patients with Leber's hereditary optic neuropathy and idebenone trial: a prospective, interventional, non-comparative study.

Leber's hereditary optic neuropathy (LHON) is a mitochondrial neuropathy that causes acute vision loss. Idebenone, a short-chain ubiquinone analog that preserves mitochondrial function is thought to suppress disease progression in early-onset LHON patients. We investigated the effects of idebenone in Japanese LHON patients. Prospective, interventional, non-comparative study in patients with definite LHON diagnosis, under trial registration number UMIN000017939. Fifty-seven patients received 900 mg/day idebenone for 24 weeks. We measured baseline best-corrected visual acuity, visual fields, critical fusion frequency and retinal ganglion cell layer complex thickness; we assessed efficacy at 24 and 48 weeks, and safety throughout. Patients were predominantly male (91.2%) and most had an mt.11778G>A mutation (94.7%). All patients tolerated idebenone therapy well. Data from the 51 mt.11778 patients were compared with their baseline data. At 48 weeks, significant improvement in best-corrected visual acuity was observed in 17 patients (33.3%). Furthermore, 25.5% of patients showed improvements in visual fields and 33.3% in critical fusion frequency. However, retinal ganglion cell layer complex thickness was significantly reduced. Among patients who started idebenone >1 year after disease onset, visual improvement was found in 12 (38.7%). Among patients who developed LHON before 19 years of age, visual improvement was found in 11 (42.3%). Idebenone's potential and favorable safety profile were confirmed in Japanese LHON patients. However, this study had no placebo group; therefore, we need to undertake a prospective intervention study to further investigate the therapeutic effects of Idebenone in Japanese LHON patients.