By: Patrick Totty
Successful clinical trials of a topical drug called mecamylamine may lead to a potent new treatment for the diabetes-induced eye disease known as macular edema. Diabetic macular edema* involves the part of the retina called the macula. High blood sugar levels inflame its blood vessels, leading to leakiness and fluid accumulation. Left uncontrolled, those symptoms can lead to blurriness, impaired vision, and even blindness.
In the early-stage human experiments with mecamylamine, conducted by the Wilmer Eye Institute at Johns Hopkins University School of Medicine in Maryland, patients with diabetic macular edema gave themselves mecamylamine eye drops twice daily for 16 weeks. The patients met with researchers every four weeks to track results and progress.
At the end of the 16 weeks, 40 percent of the participants showed “significant improvement” in the thickness of their retinas and/or their overall vision. (Forty percent of participants showed no change, and 20 percent had their condition worsen.)
One of the most encouraging aspects of the study was the fact that topical application alone was enough for the drug to reach retinal blood vessels. The ability to bypass inconvenient or time-consuming laser surgery or vitrectomies would be a boon to people suffering from the condition.
Mecamylamine was developed by the South San Francisco, California, biotech company CoMentis, Inc., with funding from the Juvenile Diabetes Research Foundation through its Industry Drug Development Partnership Program. In the past year, the JDRF has funded $22 million worth of research on “Complications Therapies” for diabetes.
The results of the study were published in the American Journal of Ophthalmology.
*Diabetic macular edema is an advanced form of diabetic retinopathy, a common complication in people with diabetes. Diabetic retinopathy is a progressive disease. Over time, high blood sugar levels can swell the retina and begin to destroy its small blood vessels. As the disease advances, the body responds by growing new blood vessels along the retina. However, these vessels are fragile and can hemorrhage easily, sending blood into the vitreous humor-the part of the eye filled with a gel-like substance-causing blurred vision, floaters, and vision loss. Other complications include scarring and retinal detachment, as well as glaucoma.
* * *