Medical update: New and Emerging Treatments for dry AMD
One of the most exciting facets of being Medical Retinal specialists is the continued evolution of Age-related Macular Degeneration (AMD) therapies.
We have come a long way from the days of photo dynamic therapy and fledgling anti-VEGF treatments. We now have agents able to restore and maintain vision with wet (neovascular) AMD, such as Avastin, Aflibercept / Eylea and Faricimab. As well as agents potentially capable of stabilizing dry (atrophic) AMD. This article specifically looks at what is new in the field of dry (atrophic) AMD.
Several therapeutic approaches have been investigated for dry AMD and are in different stages of clinical trials, but as yet there is no agent that is shown to be a real “game-changer” in management. One of the main goals is to find treatments that prevent or limit geographic atrophy, the advanced stage of dry AMD. To support treatment, it is very important for patients with dry AMD to have good baseline data which will show the extent of the disease and monitor progression, including autofluorescence photography and OCT scans.
Some new treatments for dry AMD under development include those targeting the complement pathway and senolytic therapy.
One of the components of our immune system is the complement pathway. It is a complicated set of pathways, where one step cascades onto another, like a domino effect. AMD has been shown to be activated by immune pathways, especially the complement pathway and a lot of research is concentrating in this area.
One treatment that targets a complement pathway is Pegcetacoplan, administered by intravitreal injection (reported in Viewpoint #21). Study results for the complement inhibitor Pegcetacoplan (FILLY trial) show that geographic atrophy growth can be slowed. However, the benefits of treatment only became apparent after 18 months of monthly injections. Overall there was a ~30% reduction in progression from early dry AMD to severe dry AMD. There have been some significant adverse effects recently reported, including sudden, permanent vision loss and these are now under urgent review.
Other complement inhibitors are being studied. The GATHER study looking at avacincaptad Pegol, another intravitreal agent, has shown reduction in the growth of geographic atrophy by 30% after monthly injections. Other pathways for dry AMD research include senolytic treatments; treatments that slow the ageing process in the eye by removing ageing (senescent) cells.
While these treatments show promise, and it is exciting to have proof that the process of geographic atrophy can be slowed, the treatments are not currently funded nor readily available yet in New Zealand. What it does indicate however, is that there is significant current and ongoing research, so there is hope for the future.
Dr Jo Sims & Dr Ainsley Morris
Glossary
AMD = Age-related Macular Degeneration = MD
Neovascular AMD = wet MD
Atrophic AMD = Geographic atrophy = advanced stage dry MD
