A randomized clinical trial comparing fixed vs pro-re-nata dosing of Ozurdex in refractory diabetic macular oedema (OZDRY study)

To compare the clinical effectiveness and safety of 5-monthly fixed dosing vs pro-re-nata (PRN) Ozurdex treatment in patients with refractory diabetic macular oedema (DMO).Prospective, multicentre, randomized active-controlled non-inferiority clinical trial.Participants were 100 patients who attended Medical Retina Clinics for management of centre-involving refractory DMO.Participants were randomized 1 : 1 to either 5-monthly fixed dosing or optical coherence tomography (OCT)-guided PRN regimen of Ozurdex therapy for DMO. Data were collected on best-corrected visual acuity (BCVA), patient-reported outcome measures (PROM), macular thickness and morphology, diabetic retinopathy status, number of injections and adverse events from baseline for a period of 12 months.Main outcome measuresThe primary outcome was the difference between arms in change in BCVA from baseline to 12 months. The prespecified non-inferiority margin was five ETDRS letters. Key secondary outcomes included change in PROM scores, change in macular thickness, change in retinopathy and macular morphology, and safety profile.The mean change in BCVA was +1.48 (SD 14.8) in the fixed arm vs -0.17 (SD 13.1) in the PRN arm, with adjusted effect estimate +0.97, 90% confidence interval (-4.01, +5.95), P=0.02 (per protocol analysis). The conclusions of the ITT analysis were primarily supportive, -0.34 (-5.49, 4.81) P=0.07, but sensitive to an alternative assumption on missing data, +0.28 (-4.72, 5.27) P=0.04.The mean change in BCVA with 5-monthly fixed dosing of Ozurdex was non-inferior to OCT-guided PRN Ozurdex therapy for refractory DMO based on a per protocol analysis.