Intravitreal Dexamethasone Insert in Chronic Diabetic Macular Edema Recalcitrant to anti-Vascular Endothelial Growth Factor Therapy

Abstract

Purpose : A significant proportion of patients with diabetic macular edema (DME) on anti-vascular endothelial growth factor (VEGF) therapy fail to completely respond to monotherapy. These patients have a high treatment burden even in absence of clinically significant improvement. In this study, we investigate the role of intravitreal dexamethasone insert (IDI) in patients with chronic diabetic macular edema recalcitrant to anti-VEGF monotherapy.

Methods : A non-randomized interventional study was performed among patients with chronic DME on anti-VEGF therapy beginning in June 2018. Patients required 3 minimum injections before consideration of IDI adjunctive therapy. At the fourth visit, failure to respond was evaluated. Failure to respond was defined as failure of vision to improve by 1 line or more, central subfield thickness (CST) > than 320μm, or failure of CST to improve by 10% or more. Patients with prior diagnosis of glaucoma, cup-to-disc ratio of 0.8 or more, or patients with history of steroid-responsive ocular hypertension were excluded. If previously treated with intravitreal steroids, a 3 month wash out period was required. Patients were analyzed at week 6, 12, 24 and at 1 year.

Results : Seven eyes of 5 patients were enrolled and followed for a mean of 14 months. All patients were male, with an average age of 67.1 years. The mean number of prior injections was 30.7 (range 8-58). Patients received an average of 2.7 dexamethasone injections per person-year (PY), and required breakthrough anti-VEGF injection at 1.8 injections/PY. Mean pre-treatment visual acuity was 0.457 LogMAR, improving to 0.335 LogMAR at visit 1, and stable at 0.321 at 1 year. Mean CST pre-injection was 388μm, improving to 335μm at 24 weeks, remaining stable at 324μm at 1 year (Δ-64μm). Two of 7 eyes required topical ocular hypotensives.

Conclusions : Intravitreal dexamethasone insert appears effective in patients with long-standing recalcitrant DME. In our patient series, IDI resulted in excellent anatomic improvement on SD-OCT, as well as modest visual improvement. Additionally, IDI appears effective in reducing overall injection burden in these patients who may otherwise receive years of monthly treatments. Overall safety profile was like prior studies, though this study is not powered to detect uncommon side-effects.

This is a 2020 ARVO Annual Meeting abstract.