The “Other” AMD

Many people may be familiar with dry AMD, characterized by RPE pigment or drusen formation, as well as wet AMD, characterized by the choroidal neovascular membrane and associated leaking and bleeding. But the third form, Geographic Atrophy (GA) ,a subset of dry AMD, is characterized by defined areas of RPE loss. While it may be less known and more poorly understood, it is equally as important, often under-reported, and responsible for significant vision loss in patients with the disease. It is responsible for severe vision loss in 20% of all patients with AMD, and 42% of patients with GA are legally blind

GA is currently estimated to affect more than 1 million Americans, almost as common as wet AMD. Its onset increases with age, as does all forms of AMD, with a mean onset of 67.4 +/-5.2 years. It is found in 3.5% of pts over 75.

Due to recent research, more is known about GA lesions than previously. We now know that once a lesion begins, it grows at a rate around 1.2-2.8 mm 2 per year. We also know larger lesions enlarge faster than smaller lesions, and on average the rate of growth is faster toward the periphery than toward the fovea. Further, it takes approximately 2.5 years median time to develop central GA after initial GA diagnosis, and 7 years to develop bilateral GA after the development of GA in the first eye.

Currently, there are a few treatments in the pipeline for GA. These agents have been shown to slow down the progression rate of the GA lesions. The one that may hold the most promise is pegcetacoplan, a C3 inhibitor, by Apellis Pharmaceuticals. Two separate phase 3 studies showed that intravitreal pegcetacoplan reduced GA lesion growth and demonstrated a favorable safety profile at 18 months. In the OAKS study, GA lesion growth was reduced by 22% with monthly and 16% with every-other-month treatment. The DERBY study demonstrated reduced lesion growth of 13% with monthly and 12% with every-other-month treatment. The company plans to submit it to the FDA later this year. Hopefully, this will be the first approved treatment for GA and will help preserve vision for those patients living with GA.

Both Visible Genomics’ genetic tests evaluate for the risk of Geographic Atrophy. The AMDiGuard Lifetime Risk Assessment can assess an individual patient’s risk of developing advanced AMD (GA or CNVM associated with neovascular AMD) over their lifetime. The AMDiGuard Progression Assessment can assess a patient with early AMD risk to advanced AMD, including GA, over the next 5,10, 20, or up to 30 years. This information can be used to create an individualized treatment plan, consisting of follow-up and risk counseling. To learn more, go to Visible Genomics.