Katherine Talcott, MD: Baseline EZ Integrity Features Predict GA Progression

Baseline ellipsoid zone (EZ) integrity features on spectral-domain optical coherence tomography (SD-OCT) could help predict eyes at risk for fast progression of geographic atrophy (GA), according to a post-hoc analysis of the GATHER1 and GATHER2 trials.

These insights into the impact of baseline predicts of GA growth, presented at the American Society of Retina Specialists (ASRS) 42nd Annual Meeting, could influence GA disease management decisions, particularly with avacincaptad pegol.

“We found that for each of the EZ metrics that we looked at, there was a significant difference between the patients who had the GA that was growing the fastest and those that were growing the slowest,” presenting investigator Katherine Talcott, MD, Cole Eye Institute, Cleveland Clinic, told HCPLive. ”Basically, if you had an increase in any of these EZ metrics, you were more likely to have faster GA growth.”

GA lesion growth rates can vary across eyes. SD-OCT can be used to examine the integrity of specific retinal features, including EZ, an imaging biomarker of photoceptor structure. Using the GATHER1 and GATHER2 clinical trials, this post hoc analysis focused on the link between baseline EZ integrity features with GA growth rate.

GATHER clinical trials evaluated the efficacy and safety of avacincaptad pegol versus sham in eyes with GA. The growth rate of GA was measured by fundus autofluorescence over the first 12 months of both trials and estimated for each patient in the pooled sham group (n = 332).

Categories were broken down by quartile of GA growth rate: “very slow,” “slow,” “moderate,” and “fast.”

SD-OCT scans were used to determine multiple measures at baseline, including panmacular total and partial EZ attenuation, or the percentage of the macular with EZ-retinal pigment epithelium (RPE) thickness of 0 µm and ≤20 µm, respectively.

Partial EZ-GA gap was determined as the percentage of the macular with EZ-RPE thickness ≤20 µm minus the percentage of the macular occupied by GA, calculated based on the area of total attenuation of the RPE.

Upon analysis, faster GA growth was linked to greater baseline total and partial EZ attention. For patients with very slow (n = 70), slow (n = 69), moderate (n = 69), and fast (n = 69) GA growth, baseline mean total EZ attenuation was 22.7%, 28.3%, 31.6%, and 38.6%, respectively.

Meanwhile, the baseline mean partial EZ attenuation was 36.0%, 43.8%, 48.2%, and 60.1%, respectively.

Faster growth rates were also correlated with a higher baseline partial EZ-GA gap. Baseline mean partial EZ-GA gap was 22.0%, 25.7%, 28.1%, and 36.9%, respectively.

“If we can get a better sense of patients sitting in front of us, if their GA is going to grow faster, it would allow us to better counsel patients and maybe start treatment,” Talcott added. “Our research is trying to develop metrics to better understand that.”

Disclosures: Relevant disclosures for Talcott include Apellis, Bausch and Lomb, Genentech, Iveric Bio, Regenxbio, and others.

Reference

_{Talcott K. Baseline Ellipsoid Zone Integrity Features as Predictors of Geographic Atrophy Growth Rate in the Phase 3 GATHER Clinical Trials. Paper presented at the American Society of Retina Specialists (ASRS) 42nd Annual Meeting. Stockholm, Sweden. July 17-20, 2024.}