Intravitreal dexamethasone insert in diabetic macular edema super-refractory to anti-vascular endothelial growth factor therapy

Abstract

Background: Some patients with diabetic macular edema (DME) fail to completely respond to anti-vascular endothelial growth factor (VEGF) therapy. These patients have a high treatment burden in the absence of significant improvement. We investigate the role of intravitreal dexamethasone insert (IDI) in eyes with super-refractory DME.

Methods: A non-randomized interventional study was performed among eyes with super-refractory DME refractory to anti-VEGF therapy. Eyes were treated with IDI after failing clinical response to anti-VEGF, with a minimum of 15 prior. Failure to respond was defined as failure of vision to improve at least one line on Snellen Acuity chart, central subfield thickness (CST) greater than 320 μm, or failure of CST to improve by 10% or more. Eyes with glaucoma or prior uncontrolled steroid-responsive ocular hypertension were excluded. Patient outcomes were analyzed at weeks 6, 12, 24, and year 1.

Results: Six eyes of four patients were identified. All patients had failed aflibercept. The mean number of prior anti-VEGF injections was 34.5. Eyes received an average of 2.92 dexamethasone injections per person-year (PY) and required breakthrough anti-VEGF injection at 1.95/PY. Mean pre-treatment visual acuity was 0.475 LogMAR, improving to 0.342 at week 6, and 0.375 at 1 year. Mean CST pre-injection was 386.5 mm, improving to 315 mm at 1 year. No glaucoma developed.

Conclusions: Intravitreal dexamethasone insert appears effective in eyes with super-refractory DME. IDI resulted in excellent anatomic improvement on SD-OCT as well as modest visual improvement. Injection burden was reduced in those who may otherwise receive years of monthly treatments.

Keywords: DME; Diabetic macular edema; Ozurdex; aflibercept; anti-vascular endothelial growth factor; intravitreal dexamethasone.