Evolution of Geographic Atrophy in Patients Treated with Ranibizumab for Neovascular Age-related Macular Degeneration

Abstract

 

Purpose

 

To evaluate the incidence and progression of geographic atrophy (GA) in subjects enrolled in a prospective clinical study assessing the effects of ranibizumab therapy on choroidal vessels in eyes with neovascular age-related macular degeneration (nAMD).

 

Methods

 

From 2009 to 2012, 75 subjects with nAMD enrolled a single study eye. Each subject received 4 monthly intravitreal injections of 0.5 mg ranibizumab followed by pro re nata injections until a fluid-free macula was achieved on optical coherence tomography (OCT). GA was defined on fundus autofluorescence (FAF) as a region of hypo-autofluorescence (≥0.05 mm² area or ≥250 µm diameter) located within the macula, corresponding to sharp margins and visible large choroidal vessels on color fundus photography and/or late fluorescein angiography and retinal pigment epithelium (RPE) loss on OCT. GA areas were outlined then analyzed using square root transformation. Wilcoxon rank-sum test was used to compare continuous data.

 

Results

 

The 69 subjects (mean age 78.1±8.6 years) with ≥1 year of follow-up were followed for an average of 40.0±13.6 months. Over half (66.7%) had received prior treatment for nAMD in the study eye. Of the 64 subjects with baseline quality images, 23 (35.9%) had GA in the study eye at baseline. GA of 21 eyes with measurable areas enlarged on average by 0.27±0.24 mm/year and 13 (61.9%) were <1.3 mm² in size at baseline, whereas the remaining were 1.3-11.3 mm².<br /> <br /> Of the 41 (64.1%) study eyes without baseline GA, 8 (19.5%) developed GA during the study, all by 2 years of enrollment. Two (25%) of the eyes that developed GA were treatment naïve and 4 (50%) did not have GA in the fellow eye at baseline. By comparison, 17/33 (51.5%) eyes that did not develop GA were treatment naïve and 22/33 (66.7%) did not have GA in the fellow eye. Those who developed GA were also older than those who did not develop GA (mean age 83.8 and 76.5 years, respectively, P Value <0.01) and received fewer injections in the first year (mean number 6.9 and 10.4, respectively, P Value <0.05). FAF images of eyes that developed GA all showed abnormal RPE at baseline.

 

Conclusions

 

Approximately 20% of subjects receiving ranibizumab therapy without GA at baseline developed new GA. FAF may play a role in identifying eyes that are susceptible to developing GA. Other risk factors for GA might include increasing age and GA in the fellow eye.