A prospective cohort study published in the American Journal of Ophthalmology investigated the relationship between geographic atrophy (GA) growth rate and multimodal imaging markers with patient demographics.
Give me some background first.
Current FDA-approved treatment options available for GA secondary to AMD now include:
- Syfovre (pegcetacoplan; Apellis Pharmaceuticals)
- Izervay (avacincaptad pegol; Iveric Bio, an Astellas company)
While these new therapies have proved to be game-changers for the GA treatment field, less is known about imaging biomarkers for GA progression once it’s established, according to researchers.
Thus, investigators sought to identify an association between common imaging biomarkers and patient demographics with GA growth rate.
Now, talk about the study.
Researchers evaluated 121 eyes of 66 patients diagnosed with advanced non-neovascular AMD (nnAMD), comprising 32 (48%) male patients and 94% Caucasian patients (62/66).
Participant criteria included:
- Aged 55-99 (mean age of 81.6)
- Diagnosed with AMD in at least one eye (none for control group)
- No history of choroidal neovascularization or prior intravitreal injections
And how were they categorized?
Researchers categorized the participants—taken from the University of Colorado AMD registry—using the classification described by the Beckman Initiative for Macular Research Committee.
The presence of GA was defined by using the Classification of Atrophy Meetings (CAM) criteria for outer retina atrophy (cRORA), which requires the eye to meet three criteria:
- Loss of outer retinal layers
- Loss of RPE
- choroidal hyper-transmission of at least 250 µm in size in patients with AMD and no other retinal disease
How was the study conducted?
Multimodal images were taken of participants and reviewed by two vitreoretinal specialists for imaging biomarkers at enrollment.
A third vitreoretinal specialist reviewed patient images and records to ensure no conversion to nAMD or other concomitant retinal or uveitis diseases occurred during the study.
GA growth rate and square-root transformed (SQRT) GA growth rate were evaluated during enrollment and the follow-up visit.
SQRT GA growth rate was calculated by taking the square root of the consensus GA size measurements at enrolment and final visit then subtracting the SQRT at enrolment measurement from the SQRT measurement at the final visit. The researchers divided this number by the number of days between enrollment and the final visit and then multiplied the value by 365 to determine the growth rate per year.
Findings?
There was a significant association between SQRT GA growth rate and:
- Increasing patient age (β=0.005, 95% confidence interval (CI): 0.001 to 0.009, p=0.010)
- Female sex (β=0.069, 95% CI: 0.005 to 0.133, p=0.035)
Conversely, no significant association was noted between SQRT GA growth rate and:
- Race
- Smoking history
- Family history of AMD
However, a negative association was identified between SQRT GA growth rate and body mass index (BMI) (β=-0.0050, 95% CI: -0.00098 to -0.0002, p=0.041).
Expert opinion?
The researchers stated that this data and potential further research could help better determine which patients would benefit from current and future treatment options.
They added: “Given the cost, time, and safety concerns of the currently available GA therapies, careful patient selection of those at greatest risk for rapid disease progression is critical.”
Anything else?
The researchers also commented that their findings support prior research and provide further insight into potential imaging biomarkers associated with GA growth rate.
Limitations?
The researchers note that the study sample size was small and that a larger size would enhance the ability to detect changes in rates of GA growth of certain biomarkers by either low, medium, or high—allowing for the development of a more comprehensive risk score.
Take home.
Patients may have a more rapid progression of GA lesions and benefit from treatment if they:
- Are older
- Are female
- Have non-exudative SRF
- Have iRORA
- Have very thin choroids