Emerging treatments for dry age-related macular degeneration with geographic atrophy: a systematic review

Abstract

extracellular deposits (drusens) are formed between RPE and the Bruch membrane, leading to central scotomas and metamorphopsia. In the advanced stage, drusen regresses and hyperpigmentation occurs, resulting in GA. 6 On optical coherence tomography (OCT), GA is characterized by the atrophy of RPE, photoreceptors, choriocapillaris, and outer nuclear layer. 7 Unlike neovascular AMD that can be treated with anti-vascular endothelial growth factor, dry AMD with GA secondary to RPE or photoreceptors damage cannot be reversible by current therapies. 8 Hence, smoking cessation and vitamin or nutritional supplements remain the main option to improve the prognosis of dry AMD. 9 The Age-Related Eye Disease Study 2 (AREDS2) showed that dietary supplements can lower the risk of the development of wet AMD but have no effects on reducing annual GA lesion area. 10 This prompts studies to develop novel strategies to minimize GA lesions in patients with dry AMD and to reduce visual morbidity.We aim to systematically review clinical studies published within 10 years about emerging treatments of GA secondary to dry AMD and their effectiveness in preserving vision. We categorized the treatments into complement inhibitors, diet and supplement, cell-based therapies, and pharmacological agents. The efficacy, safety profile, and limitations of various therapies are discussed and compared. MethodsThe PubMed database was searched on 19 June 2021 using keywords: 'treatment' and 'geographic atrophy' or 'dry age-related macular degeneration'. Only clinical trials and randomized controlled trials published within 10 years and written in English language were included. Of 121 articles identified, 20 clinical studies describing the novel therapies for dry AMD with GA were included. Review papers, metaanalyses, and case reports were excluded. The 20 studies were manually curated for subject relevance through abstract or full text by one author, followed by discussion on the relevance with another author who made the arbitration when there was disagreement on article selection (Figure). ResultsThe emerging treatments of dry AMD with GA were categorized into complement inhibitors (Table 1), diet and supplement (Table 2), cell-based therapies (Table 3), and pharmacological agents (Table 4).