Anatomical effects of dexamethasone intravitreal implant in diabetic macular oedema: a pooled analysis of 3-year phase III trials

BACKGROUND/AIM To assess long-term effects of dexamethasone intravitreal implant (DEX implant) monotherapy on retinal morphology in diabetic macular oedema (DME). METHODS Two multicentre, masked, phase III studies with identical protocols randomised patients with DME, best-corrected visual acuity of 34-68 Early Treatment Diabetic Retinopathy Study letters and central subfield retinal thickness (CSRT) ≥300 µm to DEX implant 0.7, 0.35 mg or sham procedure. Patients were followed up for 3 years (39 months if treated at month 36), with retreatment allowed at ≥6-month intervals. Patients needing other macular oedema (ME) therapy exited the study. Changes from baseline in CSRT, macular volume and ME grade, area of retinal thickening, macular leakage, macular capillary loss and diabetic retinopathy severity were assessed. RESULTS After 3 years, more eyes treated with DEX implant 0.7 and 0.35 mg than sham showed improvement (although small) in ME grade (p<0.05 vs sham). DEX implant 0.7 mg delayed time to onset of two-step progression in diabetic retinopathy severity by ∼12 months. DEX implant 0.7 and 0.35 mg produced small, non-sustained reductions in macular leakage but had no significant effect on macular capillary loss. CONCLUSIONS DEX implant 0.7 or 0.35 mg, administered at ≥6-month intervals over 3 years, produced sustained retinal structural improvement in DME. TRIAL REGISTRATION NUMBER NCT00168337 and NCT00168389.