Morphologic parameters affect anti-VEGF therapy outcome

Patients receiving anti-vascular endothelial growth factor (anti-VEGF) therapy to treat neovascular age-related macular degeneration (AMD) exhibit a distinct response pattern and time course of certain retinal morphologic changes. Some of the changes, such as intraretinal cysts, subretinal fluid and pigment epithelial detachments, can affect the patients' potential for visual gain.

Those were the findings of a study conducted by Researchers at Vienna Reading Center, Department of Ophthalmology, and the Institute of Environmental Health, Center for Public Health, Medical University of Vienna, Austria. The researchers conducted a subanalysis of the EXCITE (Efficacy and Safety of Ranibizumab in Patients with Subfoveal Choroidal Neovascularization Secondary to Age-Related Macular Degeneration) phase IIIb clinical trial.

The researchers studied 353 treatment-naïve patients with subfoveal choroidal neovascularization. The patients were randomized to receive either quarterly (0.3 mg or 0.5 mg) or monthly (0.3 mg) doses of ranibizumab. The duration of treatment was 12 months: a loading phase consisting of 3 consecutive monthly injections, then 9 months of either the monthly or quarterly injections.

The researchers identified a significant correlation between a reduction in central retinal thickness and an increase in best-corrected visual acuity (as measured using the Early Treatment Diabetic Retinopathy Study protocol) (P

Retinal morphology was assessed by time-domain optical coherence tomography, and the researchers found that the proportion of patients showing changes decreased significantly in all three treatment groups (P

In terms of visual acuity, the baseline presence of intraretinal cysts resulted in lower best-corrected visual acuity over the study period; recurrence during the study had no additional negative effect. Baseline presence of subretinal fluid did not affect visual recovery, but patients who had a recurrence during follow up tended to display an additional negative effect on function (P = 0.06). Pigment epithelial detachments had a negative effect on visual outcome only when they occurred in combination with subretinal fluid or intraretinal cysts.

The study was published online in Ophthalmology.