Imaging-based Biomarkers as Predictors of Response to Anti-VEGF Therapy in Idiopathic Choroidal Neovascularization

Abstract

Purpose: The purpose of this study was to identify biomarkers that predict the response of treatment-naive idiopathic choroidal neovascularization (iCNV) to anti-VEGF treatment.

Methods: Fourteen eyes diagnosed with iCNV underwent a dilated fundus examination, Swept Source Optical Coherence Tomography (SS-OCT) and Optical Coherence Tomography - Angiography (OCT-A), and were given an anti-VEGF injection. The same examinations were repeated at every follow-up visit. Analysis of the pre- and posttreatment images was done to identify possible biomarkers which were evaluated to check association with decreased need for multiple anti-VEGF injections.

Results: At presentation, 11 patients showed a compact pattern, while three patients showed an arborizing pattern on OCT angiography (P = 1). On follow-up imaging, seven patients showed a marked response, five patients showed a moderate response, and two patients showed a mild response to anti-VEGF injection. Among the seven patients showing a marked response, only one required a repeat injection (P = 0.03). On analysis of SS-OCT, a novel Retinal Pigment Epithelium (RPE) healing response was observed in posttreatment imaging of six patients (P = 0.59).

Conclusion: A "marked" response to the first anti-VEGF injection results in a more sustained response and is a positive prognostic factor. RPE healing response is an interesting observation that merits further evaluation. Morphology of neovascular membranes has no effect on long-term need for multiple anti-VEGF injections.

Keywords: Anti-VEGF; OCT; OCT-A; biomarkers; idiopathic choroidal neovascularization.

Figure 1

Pre- and posttreatment images of four patients. All OCT-A images have been manually segmented to the level of the outer retina. Images in the subset show the B-scan segmentation level of respective OCT-A images. The two pairs of images on the left (A1-A2 and B1-B2) show compact morphology with marked resolution. Images C1-C2 show a large arborizing lesion with moderate response to anti-VEGF. Images D1-D2 also show an arborizing lesion with moderate response to anti-VEGF

Figure 2

Pre- and posttreatment images from four patients to illustrate the “RPE Healing” response. In all four posttreatment images, the SRHM appears to be covered by a distinct hyper-reflective membrane which is continuous with the RPE. In images A2, B2, and C2, this hyper-reflective membrane (red arrowhead) is continuous and fully covers the SRHM. Note that the membrane is of irregular thickness in A2, but has uniform thickness in B2 and C2. In image D2, this membrane (red arrowhead) is discontinuous and covers the SRHM only partially