A drug based on vitamin A could prevent millions from going blind as
they get older, doctors believe.
The treatment was able to stop the most common cause of blindness in
old age during trials.
Researchers behind the drug, fenretinide, found it halted the advance
of age-related macular degeneration, for which there is currently no
They targeted the most prevalent form of the condition, known as
‘dry’ AMD, which is caused by the deterioration and death of cells in
the macula – the part of the retina used to see straight ahead.
The disease robs sufferers of their sight by creating a blackspot in
the centre of their vision.
It can make it impossible to carry out everyday tasks such as
reading, driving and watching television.
While the less common ‘wet’ form can be treated, nothing can be done
to help the bulk of patients.
The U.S. research studied fenretinide, which is derived from vitamin
A, the vitamin found in carrots, and which was originally designed to
Almost 250 men and women with dry AMD took a fenretinide pill a day
or a placebo.
In the highest dose, the drug halted visual deterioration after a
year. This suggests that while it was unable to do anything to stop
cells that were already damaged from dying, it protected healthy cells.
Although the research is still preliminary, it offers promise of a
treatment for the disease.
It affects millions across the world and 300,000 Britons. The number
of UK sufferers could more than treble to one million within 25 years as
the population ages.
Dr Jason Slakter, of New York University School of Medicine, said:
‘There are currently no effective treatments for dry AMD and the need
for finding one is grave.
‘Our study wasn’t designed to give a final answer.
‘It was designed to see if there was a biological effect and if the
drug was working in the way we’d expect and to find out if it was well
tolerated by patents.
‘I think we answered all of these points favourably. The bottom line
is that I am excited about doing more studies.’
Further, larger trials are planned for the end of next year.
If the drug lives up to its initial promise, it could be in
widespread use for dry AMD by 2015.
The treatment works because in normal circumstances the eye needs
vitamin A to help it see. The retina naturally uses the vitamin and is
helped to do so by a compound called retinol binding protein, or RBP.
However in some patients, the vitamin can produce poisons that kill
the delicate cells, leading to loss of vision.
Fenretinide acts as a decoy, attaching itself to the RBP and stopping
vitamin A from causing harm, the American Academy of Ophthalmology’s
annual conference heard.
Wet AMD, in which tiny blood vessels bleed into the retina, is less
common, but progresses more rapidly, with central vision being lost
within months of diagnosis.
Caught early enough, wet AMD can be stopped in its tracks by a
technique called photodynamic therapy, which uses a light-activated dye
to destroy abnormal blood vessels. Drug treatments are also available.
Fenretinide also halved the odds of the patients, who already had dry
AMD, going on to develop wet AMD.
A spokesman for the research team said: ‘Years of use of fenretinide
to treat cancers, rheumatoid arthritis have shown it to be safe and