A clinical trial has found that a quarter of patients who took idebenone for 24 weeks enjoying such improved vision that they were able to read an entire row of letters on a standard chart.
British researchers say it is the first evidence of a treatment that can reverse the effects of a mitochondrial disorder, affecting the energy factories of the eye’s cells.
The drug, manufactured by Santhera Pharmaceuticals, will now be assessed by European regulators before it can be offered to more patients.
Prof Patrick Chinnery of Newcastle University, which led the trial, said: “This is the first proven treatment for a mitochondrial disorder. 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. For these patients, it can mean a vast improvement in their quality of life.
“While we know that their vision is not what it once was, we also know that this treatment can dramatically improve their lives – some were able to move around more easily or even see family photos again.”
In a paper published in the journal Brain, he and colleagues describe how they recruited 62 patients suffering from Leber’s Hereditary Optic Neuropathy (LHON), an inherited condition that can see people with normal vision lose the sight in one eye then the other within six months.
It is among the most common causes of inherited blindness and affects about 2,000 people in Britain.
In the trial, patients were either given the new drug or a placebo for 24 weeks, after which time several taking idebenone, marketed as Catena, were found to have greatly improved eyesight.
Nine of the 36 patients taking the drug were able to read at least one row of letters on a chart, while none of the 26 on the placebo showed the same improvement.
Those who had better vision in one eye than the other, likely to be at an earlier stage of the condition, showed the greatest improvement.
The drug works by penetrating the mitochondria in the eyes and “mopping up” toxic molecules that damage tissue.