FDA Panel Recommends Drug for Diabetes Vision Loss
Currently, there are no FDA (Food and Drug Administration) approved drugs for treatment of diabetic macular edema, a condition that affects more than half a million people in the United States. An FDA advisory panel has recommended the agency approve Lucentis for treatment of this eye disease, although the FDA does not have to abide by the panel's recommendation.
New hope for diabetic macular edema in sight
Diabetic macular edema is an eye complication that develops from another complication of diabetes, called diabetic retinopathy, a condition in which the blood vessels in the eye are damaged. The damaged vessels leak fluid (plasma constituents) into the macula, the central part of the eye that contains nerve cells (cones) that are responsible for sensing light. If the macula fills with fluid, blurry vision is the result, and it can be severe.
The severity of diabetic macular edema depends on several factors, including the degree of diabetic retinopathy, how long a patient has had diabetes, the presence of high blood pressure, the level of fat in the blood (cholesterol and triglycerides), and type of diabetes a person has.
The standard treatment of diabetic macular edema includes glycemic control, blood pressure control, and laser photocoagulation, a method that can reduce the risk of visual loss, although some patients still experience permanent loss of vision after treatment.
If Lucentis is approved by the FDA for diabetic macular edema, it will be the first drug for this purpose. The FDA's Dermatologic & Ophthalmic Drugs Advisory Committee (DODAC) voted 10-to-0 to approve the 0.3 milligram dose of Lucentis (ranibizumab injection) and 8-to-2 to approve the 0.5 mg dose.
Results from two clinical trials conducted by Roche (Lucentis is made by Genentech, a member of the Roche Group) showed that 39% of patients who received the 0.3 mg dose were able to read three additional lines of letters on an eye chart after two years compared with 41% who received the 0.5 mg dose.
Lucentis and Avastin
Lucentis is in the same drug class (anti-vascular endothelial growth factor, or anti-VEGF) as Avastin (bevacizumab), another Roche drug, and one that is used to treat wet age-related macular degeneration, although it does not have FDA approval for this indication. A number of clinical trials and other research have shown bevacizumab also to be effective in the treatment of diabetic macular edema.
A study published in the May 2012 issue of the European Journal of Ophthalmology, for example, noted that bevacizumab seems to be an effective primary treatment option for macular edema due to CRVO [central retinal vein occlusion]." A look at the US government's clinical trials website reveals dozens of studies that have been conducted or are presently underway to explore the effects of bevacizumab in the treatment of diabetic macular edema.
In another recent study published in Advances in Therapy, researchers reported on the use of bevacizumab in 29 patients with diabetic macular edema. Use of the drug resulted in improvement in visual acuity in patients who had mild, moderate, or severe diabetic retinopathy, and also caused a decrease in central macular thickness in all patients.
One reason a comparison between Lucentis and Avastin is interesting, besides their efficacy in treating diabetic macular edema, is that Lucentis costs approximately 40 times more than Avastin. If Avastin were to be approved for treatment of diabetic macular edema, the cost savings could be significant.
The best and safest way to help prevent diabetic vision loss is making lifestyle choices that keep blood glucose, blood pressure, and other risk factors for diabetes in check. On the pharmaceutical front, patients with diabetes could have a drug at their disposal that may help in the treatment of diabetic macular edema and a way to help prevent vision loss that is often a complication of the disease.
Daien V et al. Visual acuity outcome and predictive factors after bevacizumab for central retinal vein occlusion. European Journal of Opthalmology 2012 May 5. Eprint ahead of pub
Erol N et al. Vision, retinal thickness, and foveal avascular zone size after intravitreal bevacizumab for diabetic macular edema. Advances in Therapy 2012 Apr; 29(4):359-69
Food and Drug Administration
National Eye Institute Fact about Diabetic Retinopathy
Image: Wikimedia Commons