Where next for dry AMD and Stargardt research?Posted: Thursday 18 October 2018
Online searches bring up dozens of suggested treatments for macular disease, each with enthusiastic support from people who claim it has saved their sight. But which treatments are supported by evidence, and which should we be investigating next?
A team from Warwick Medical School reviewed hundreds of articles about possible treatments. One aim was to identify emerging treatments for the dry form of age-related macular degeneration (AMD), and for Stargardt disease. Their report lists several treatments that look promising but need further research.
Studies into possible treatments for dry AMD are hard to judge – for many people, their sight loss progresses so gradually that we can’t be confident about whether the treatment is making a difference for many years. The good news is that some of the drugs that look promising are already approved for other conditions, and have a known safety record, so could be approved relatively quickly.
These are the treatments which the report recommended as high priorities for research:
Statins are widely prescribed to lower high cholesterol, and there is some evidence that potent (relatively strong) statins could slow the build-up of drusen in AMD, so a trial seems justified.
A trial of a drug called fenretinide, which is also being trialled against cancer, had mixed results: its effect on the spread of dry AMD was uncertain because not everyone responded, but it did reduce progression to wet AMD.
A large study from the USA found that people taking levodopa (L-dopa) for Parkinson’s disease were less likely to have AMD. Interestingly, if they did go on to develop AMD, it was about seven years later than people who weren’t taking L-dopa. Looking at UK data to see if there’s a similar pattern might show whether it is worth testing for AMD.
Fenretinide is also a possible treatment for Stargardt disease, as it seems to prevent the build-up of the lipofuscin that damages the retina.
Another very small trial reported that people lost sight more slowly when their eyes were protected from light, so we’d like to see a larger trial of light-reducing glasses or contact lenses.
Given what we know about Stargardt disease, the antioxidants called lutein and zeaxanthin may protect the macula. We don’t have evidence for that, so a trial comparing people taking supplements with those who didn’t would help.
Like statins, fenofibrate is used to reduce blood fat levels. In a study of heart disease in people with diabetes, people taking fenofibrate were less likely to develop diabetic retinopathy. There is also some evidence that it may reduce the build-up of lipofuscin, so a trial in Stargardt seems worthwhile.