Beyond VEGF—The Weisenfeld Lecture

Abstract

Purpose To review advances made in the treatment of age-related macular degeneration (AMD) and share perspectives on the future of AMD treatment. Methods: Review of published clinical and experimental studies. Results: Inhibitors of vascular endothelial growth factor (VEGF) truly revolutionized the treatment of AMD. However, available results from longer-term studies suggest that a degenerative process is unveiled, and continues to occur, even when neovascularization is controlled. Furthermore, anti-VEGF therapy may play a role in the development of atrophic changes. We have proposed using neuroprotection to prevent atrophy, and multiple models of retinal degeneration have shown that it is necessary to block both apoptotic and necrotic cell death pathways. Despite the success of anti-VEGF therapy and the promise of neuroprotection, neither addresses the underlying cause of AMD. It has been postulated that in early AMD, the retention and abnormal accumulation of lipids in Bruch's membrane and below the retinal pigmented epithelium (RPE) lead to drusen. Thus, it is conceivable to target the retained lipoproteins and seek to remove them. In a case study and pilot multicenter clinical trial, we observed significant regression of drusen and an improvement in visual acuity in patients taking high-dose statin therapy. These results, though preliminary, warrant further investigation. Conclusion: Future treatment of AMD should be based on biology, which will require continued elucidation of the pathogenic mechanisms of AMD development. Neuroprotection represents a potential therapeutic approach, and other promising targets include immune pathways (e.g., inflammation, complement, and inflammasomes) and lipid/lipoprotein accumulation. Finally, due to the heterogeneity of AMD, future progress in therapy will benefit from improved phenotyping and classification.