A team of researchers has discovered that the experimental Alzheimer’s drug idebenone can be used to restore lost vision in patients with Leber’s hereditary optic neuropathy (LHON), according to a study in the July online issue of Brain.

LHON is a maternally inherited mitochondrial disorder that results in degeneration of the retinal ganglion cells. It is one of the most common causes of inherited blindness in the world and was previously believed to be irreversible.

“This is the first proven treatment for a mitochondrial disorder,” says author Patrick Chinnery, Ph.D., director of the Newcastle NIHR Biomedical Research Centre at Newcastle University Medical School, in the U.K. “We have seen patients who couldn’t even see an eye chart on the wall go on to read the first line down—and some even attempted the second line.”

In this 24-week study, 62 patients with LHON were randomized to receive either 900mg of idebenone per day (36 subjects) or a placebo (26 subjects). At the end of the study, nine of the 36 patients on idebenone therapy were able to read at least one row of letters on the Snellen chart. Additionally, the researchers noted that idebenone was both safe and well tolerated.

More importantly, it appears that the visual improvement remains even after therapy is discontinued.

“We are hearing from patients that they still have improved vision—even though they are no longer taking the drug, but we would like to verify this and study the effect further,” says Dr. Chinnery. “There may also be a case for offering idebenone from the first moment that LHON is diagnosed—preferably before any symptoms are shown—and a further trial would ideally examine this.”

Klopstock T, Yu-Wai-Man P, Dimitriadis K, et al. A randomized placebo-controlled trial of idebenone in Leber’s hereditary optic neuropathy. Brain 201 Jul 25. [Epub head of print]