Effect of EPI-743 on the clinical course of the mitochondrial disease Leber hereditary optic neuropathy.

OBJECTIVE: To evaluate the safety and efficacy of a new therapeutic agent, EPI-743, in Leber hereditary optic neuropathy (LHON) using standard clinical, anatomic, and functional visual outcome measures. DESIGN: Open-label clinical trial. SETTING: University medical center. Patients Five patients with genetically confirmed LHON with acute loss of vision were consecutively enrolled and treated with the experimental therapeutic agent EPI-743 within 90 days of conversion. Intervention During the course of the study, 5 consecutive patients received EPI-743, by mouth, 3 times daily (100-400 mg per dose). MAIN OUTCOME MEASURES: Treatment effect was assessed by serial measurements of anatomic and functional visual indices over 6 to 18 months, including Snellen visual acuity, retinal nerve fiber layer thickness measured by optical coherence tomography, Humphrey visual fields (mean decibels and area with 1-log unit depression), and color vision. Treatment effect in this clinical proof of principle study was assessed by comparison of the prospective open-label treatment group with historical controls. RESULTS: Of 5 subjects treated with EPI-743, 4 demonstrated arrest of disease progression and reversal of visual loss. Two patients exhibited a total recovery of visual acuity. No drug-related adverse events were recorded. CONCLUSIONS: In a small open-label trial, EPI-743 arrested disease progression and reversed vision loss in all but 1 of the 5 consecutively treated patients with LHON. Given the known natural history of acute and rapid progression of LHON resulting in chronic and persistent bilateral blindness, these data suggest that the previously described irreversible priming to retinal ganglion cell loss may be reversed.