Intravitreal Macugen for Ischaemic Diabetic Macular Oedema
Status:
Completed
Trial end date:
2013-03-01
Target enrollment:
Participant gender:
Summary
Diabetic macular oedema (DME) is one of the leading causes of blindness in the United
Kingdom's working population. It affects the macula, which lies at the centre of the retina,
at the back of the eye. Damage to the macula can occur either because the blood supply is
reduced (ischaemic DME), or because the blood vessels are leaking excessively (exudative
DME).
A chemical called vascular endothelial growth factor (VEGF) may underlie some of the
abnormalities seen in DME. Studies have shown that VEGF encourages leakage of fluid from
blood vessels and increases the stickiness of white blood cells. When white blood cells are
sticky they can attach to blood vessel walls. This may cause small blood vessels to block,
and lead to ischaemia.
Laser treatment often helps to stabilise exudative DME, but there is currently no recognised
treatment for ischaemic DME. Macugen (pegaptanib), a drug that inactivates VEGF, has been
tried and found to be of benefit in treating exudative DME. Since VEGF promotes ischaemia, it
is possible that Macugen will also prove to be beneficial for ischaemic DME. This has not
been tested before.
A healthy macula is essential for good vision. The innermost area of the macula, the foveal
avascular zone (FAZ), is the most important part. The FAZ is enlarged when it is ischaemic.
This is a pilot study to assess whether Macugen can reduce the size of the FAZ in ischaemic
DME. The investigators will also assess whether it can reduce retinal thickness and improve
vision in ischaemic DME. Thirty patients will be involved in the study for thirty weeks each.
They will have their eyes examined and receive an injection of Macugen into the eye every 6
weeks. The study is taking place in the Oxford Eye Hospital and is being funded by Pfizer,
the company that makes Macugen.