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  • Natural History of Geographic Atrophy Secondary to AMD

    By Lynda Seminara
    Selected By: Stephen D. McLeod, MD

    Journal Highlights

    Ophthalmology, June 2020

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    Despite termination of the phase 3 lampalizumab clinical studies in 2017 due to insufficient efficacy, the Proxima A and B portions of the trials have yielded important data on the relationship between visual function and worsening geographic atrophy (GA) from age-re­lated macular degeneration (AMD). In a comparative analysis, Holekamp et al. found that the natural history studies spotlight the major functional loss and rapid progression that are common with GA, even in early stages of the disease.

    Between May 2015 and February 2017, three cohorts were involved in these prospective studies:

    • patients with bilateral GA and no choroidal neovascularization (CNV) in either eye (Proxima A cohort; 295 participants)
    • patients with GA but no CNV in the study eye plus CNV in the other eye with or without GA (Proxima B/fel­low-eye cohort; 168 participants)
    • patients with GA only in the study eye and no CNV in either eye (Proxima B/fellow-eye intermediate AMD cohort; 32 participants)

    Follow-up duration varied because of early termination of studies. The primary outcome was the mean change in GA lesion area in the study eyes.

    At 24 months, the adjusted mean (standard error) change in lesion area was 3.87 (0.15) mm2 in the Proxima A cohort, 3.55 (0.16) mm2 in the fellow-eye CNV cohort of Proxima B, and 2.96 (0.25) mm2 in the fellow-eye interme­diate AMD cohort of Proxima B. In all three groups, visual function decreased from baseline to month 24. Adjusted mean changes in corrected visual acuity (VA) were ‒13.88 (1.40) in Proxima A, ‒9.49 (1.29) in the fellow-eye CNV cohort of Proxima B, and ‒11.48 (3.39) in the fellow-eye in­termediate AMD cohort. Mean changes in low-luminance VA were ‒7.65 (1.20), ‒7.57 (1.26), and ‒8.37 (3.02), respec­tively. In the intermediate AMD cohort, 30% of patients had conversion to GA in the fellow eye, and 6.7% had conver­sion to CNV by 12 months.

    The authors cautioned that the difference in progression rates between Proxima A and B at 24 months may relate to the variability in GA area at baseline. The high rate of conversion from unilateral to bilateral GA within 12 months underscores the stealth of the disease and suggests it may be more rapid—and have greater effects on quality of life—than previously thought.

    The original article can be found here.