Drug Treatment Benefits Some People with the Optic Nerve Disease LHON
August 4, 2011 - Leber Hereditary Optic Neuropathy (LHON) is a heritable blinding disease that damages the optic nerve. Vision loss usually begins suddenly and progresses rapidly, often over a brief period of a few weeks or months. Although the condition often begins in one eye, in most cases both eyes are ultimately affected. LHON affects more men than women and usually becomes apparent in young adulthood. Until now, it has been considered untreatable.
In the past year, however, British scientists at Newcastle University have been testing a drug called idebenone for the treatment of LHON. Idebenone has been known for decades as a free-radical scavenger and antioxidant, which reaches the brain after oral administration and may have beneficial effects in aging and diseases of the brain. Patients with LHON were recruited from Newcastle Hospitals in the UK, as well as hospitals in Munich, Germany and Montreal. The 85 patients participating in this multi-centre, double-blinded, randomized, placebo-controlled trial received either idebenone or a placebo, taking one 300 mg tablet three times a day, every day, for 24 weeks. Findings of this study were published recently in the medical journal Brain.
Idebenone at this dose was found to be safe and well tolerated. It did not benefit all of the people who took it, but at the end of the six-month trial, visual acuity and colour vision were improved in some patients taking the drug, especially those whose vision at the beginning of the trial was much better in one eye than in the other. Luckily, the treatment seemed most likely to benefit patients having the mutations that account for 80% of all LHON cases in Europe and North America.
"We saw most progress in people who had better vision in one eye than the other,” says Professor Patrick Chinnery, lead investigator on the trial. “This tends to indicate that they are at an earlier stage of the condition. While we know that their vision is not what it once was, we also know that this treatment can dramatically improve their lives."
Mike Scholes, from West Sussex in the UK, is one such patient. He lost the sight in his left eye rapidly over a five-day period, and by the time he was diagnosed with LHON seven months later, the vision in his right eye was also beginning to deteriorate.
"I couldn't see in an increasingly large area in the centre of my eyes and gradually colours disappeared. At worst the only colours I could make out were shades of blue,” says Mike. "Soon after friends spotted a clinical trial in Newcastle. I volunteered to take part and started taking the tablets three times a day – not knowing whether I was taking a placebo or the drug.”
"After just a month and a half I noticed that the area affected in the centre of my vision was smaller. The improvement continued and I began to appreciate colours again seeing yellow and most reds. The noticeable improvement in my vision means daily life is easier. I can use a computerised viewer to help me read, I can get dressed without having to use a detector for the colours of clothes and while initially I couldn't even see the eye chart, now if I get really close to a street sign I can read it."
Some people with severe vision loss also showed significant improvement in the trial. Of the 36 people who could not read an eye chart at the start of the trial, nine were able to read at least one line after six months of treatment. Still, since idebenone appeared to benefit people in the early stages of disease the most, Dr. Chinnery suggests that "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."
The drug company that sponsored this trial, Santhera Pharmaceuticals, is now seeking approval from the European Medicines Agency to offer idebenone on the open market as a standard form of treatment for LHON. Off-label use may also be possible, as idebenone has been approved in Canada (under the trade name Catena®) for the treatment of Friedreich's ataxia, another hereditary neurodegenerative condition. People diagnosed with LHON may wish to speak to their doctors about these findings.
For more details about this study, please review these information pages provided by Newcastle University.