Effect of Human Central Nervous System Stem Cell Subretinal Transplantation on Progression of Geographic Atrophy...

To evaluate the effect of subretinally transplanted human central nervous system stem cells (HuCNS-SC) on the progression of geographic atrophy (GA) in patients with nonneovascular age-related macular degeneration (AMD).

Multicenter, prospective, phase 1 open-label clinical trial.

Fifteen patients with bilateral GA solely the result of AMD.

The eye with the worst best-corrected visual acuity from each patient was selected for treatment and was considered the study eye; fellow eyes served as controls. A total of 0.25 × 10⁶ or 1.0 × 10⁶ HuCNS-SCs were infused directly into the subretinal space, superotemporal to the fovea near the junctional zone, outside the area of GA. All patients underwent spectral-domain OCT and fundus autofluorescence imaging using the Spectralis HRA+OCT (Heidelberg Engineering, Inc., Heidelberg, Germany). Total GA area in both eyes was measured at baseline and month 12 by certified reading center graders using the Spectralis Region Finder software. Sectoral (clock hour) per directional radial GA progression rates with respect to the foveal center in both eyes were calculated using the polar transformation method in Image J software (National Institutes of Health, Bethesda, MD). To facilitate comparative analysis across the cohort, all eyes were transformed to a right-eye orientation.

Total GA area and sectoral per directional GA progression rates were compared in both study and control eyes.

No statistically significant difference was found in mean change in total GA area at month 12 between study and fellow eyes (1.07 ± 0.84 mm² vs. 2.08 ± 1.97 mm²; P = 0.08). However, the month 12 sectoral per directional radial GA growth rate for the superotemporal region (i.e., the location of HuCNS-SC transplantation) showed a significantly slower progression rate in study eyes than in fellow eyes (0.29 ± 0.58 mm vs. 1.08 ± 0.65 mm; P = 0.007). The progression rate in the superotemporal quadrant of the study eye was significantly slower than in the other 3 quadrants combined (P = 0.04).

In this small pilot study, HuCNS-SC transplantation seems to be associated with slower expansion of the GA lesion in the transplanted quadrant. Larger confirmatory studies are required. Sectoral or directional analysis of growth rates of GA may be a useful approach for assessing the efficacy of locally delivered therapies.