Study Indicates When Geographic Atrophy Will Reach Fovea

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A study found a lesion will reach the fovea in 5.85 years, 6.52 years, 7.36 years, and 8.46 years if treatment reduces growth in geographic atrophy by 15%, 25%, 35%, and 45%.

Without treatment, a lesion of area 8 mm2 with a posterior edge 500 µm will reach the fovea in 5.08 years. Meanwhile, a lesion with a posterior edge 1000 µm from the will reach the fovea 10.1 years. Thus, depending on the posterior edge, a lesion may take longer to reach the fovea if geographic atrophy is treated. Current treatment of geographic atrophy includes OAKS & DERBY which was an efficacy of 26% for PM (pegcetacoplan monthly) and 22% for PEOM (pegcetacoplan every other month), and the effective radius growth is linked to lesion perimeter regardless of lesion area.

A previous study of geographic atrophy natural history calculated the geographic atrophy local border explanation rate for 237 eyes in the Age-Related Eye Disease. The study divided the retina into 7 concentric circular topographic zones centered at the fovea with 0.5 mm increments in radius up to 3.5 mm. The investigators of this previous study found that the border explanation rate increased with retinal eccentricity from 0.0985 mm/year in zone 1, close to the foveal center, to 0.2401 mm/year in zone 7.

The new study, presented at 127th Annual American Academy of Ophthalmology (AAO) conference in San Francisco, California and led by Casey Zhang, BA, intended on quantifying how long it would take a lesion to reach the central fovea due to decreasing geographic atrophy (GA) growth rates compared to natural history. The investigators examined the reduction in the rate of GA lesion area growth to the control group because the test is often used to determine the efficacy of treatment. They used the followed treatment efficacies: 15%, 25%, 35%, and 45%.

The investigators discovered without treatment geographic atrophy lesions with the posterior edge 500 µm would take 3.07-4.31 years to reach the fovea, for 1,000 µm it would take 6.13-8.62 years, and for 1,500 µm it would take 9.20-12.9 years. With monthly pegcetacoplan (PM), the lesion would reach the fovea in 3.56-5.01 (500 µm), 7.13-10 (1,000 µm), and 10.7-15 years (1,500 µm). For pegcetacoplan every other month (PEOM), geographic atrophy would reach the fovea at 3.47-4.88 (500 µm), 6.95-9.76, and 10.4-14.6 years.

“Ultimately, this study informs patient and clinical decision making by determine this time benefit of foveal preservation using GA treatments of varying efficacy compared to the natural history of GA,” the investigators wrote.

References

^{Zhang, C, Kahan, E, Friedman, S, et al. Time to Fovea: A Comparison of GA Growth with and Without Pegcetacoplan. Presented at the 2023 American Academy of Ophthalmology Annual Meeting, November 3 – 6, 2023.}