Analyses of AREDS2 data on natural history of GA provide representative data on GA evolution and enlargement. GA enlargement, which was influenced by lesion features, was relentless, resulting in rapid central vision loss. The genetic variants associated with faster enlargement were partially distinct from those associated with risk of incident GA. These findings are relevant to further investigations of GA pathogenesis and clinical trial planning.
Emixustat did not reduce the growth rate of GA in AMD. The most common adverse events were ocular in nature and likely related to the drug's mechanism of action. Data gained from this study over a 2-year period add to the understanding of the natural history of GA and the baseline characteristics affecting the growth rate of GA.
Purpose
This study assessed the safety, tolerability, and pharmacodynamics of emixustat hydrochloride (ACU-4429), a novel visual cycle modulator, in subjects with geographic atrophy (GA) associated with dry age-related macular degeneration (AMD).
Methods
Subjects were randomly assigned to oral emixustat (2, 5, 7, or 10 mg once daily) or placebo (3:1 ratio) for 90 days. Recovery of rod photoreceptor sensitivity following a photobleach was measured by electroretinography. Safety evaluations included analysis of adverse events (AEs) and ophthalmic examinations.
Results
Seventy-two subjects (54 emixustat, 18 placebo) were evaluated. Emixustat suppressed rod photoreceptor sensitivity in a dose-dependent manner. Suppression plateaued by Day 14, and was reversible within 7-14 days after drug cessation. No systemic AEs of concern were noted. Dose-related ocular AEs (chromatopsia, 57% emixustat vs. 17% placebo; and delayed dark adaptation, 48% emixustat vs. 6% placebo) were mild to moderate, and the majority resolved on study or within 7-14 days after study drug cessation.
Conclusions
In this phase II study, emixustat produced a dose-dependent, reversible effect on rod function, and an ocular AE profile that is consistent with the proposed mechanism of action. These results support further testing of emixustat for the treatment of GA associated with dry AMD.
This study replicates the results of previous natural history studies of eyes with DPED including the high rates of progression to late AMD and vision loss (regardless of progression to late AMD). The genetic associations are consistent with genes associated with AMD progression.
These data suggest that decreases in plasma free-VEGF levels are greater after treatment with aflibercept or bevacizumab compared with ranibizumab at 4 weeks. At 52 and 104 weeks, a greater decrease was observed in bevacizumab versus ranibizumab. Results from 2 subgroups of participants who did not receive injections within at least 1 month and 2 months before collection suggest similar changes in VEGF levels after stopping injections. It is unknown whether VEGF levels return to normal as the drug is cleared from the system or whether the presence of the drug affects the assay's ability to accurately measure free VEGF. No significant associations between VEGF concentration and systemic factors were noted.
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