Topical treatment of diabetic macular edema using dexamethasone ophthalmic suspension: A randomized, double-masked, vehicle-controlled study

PURPOSE: To evaluate topical dexamethasone ophthalmic suspension OCS-01 (Oculis SA, Lausanne, Switzerland) in diabetic macular edema (DME).

METHODS: This was a multicenter, double-masked, parallel-group, randomized, Phase 2 study. Patients aged 18-85 years with DME of <3 years duration, ETDRS central subfield thickness ≥ 310 μm by SD-OCT, and ETDRS letter score ≤ 73 and ≥ 24 in the study eye were randomized 2:1 to OCS-01 or matching vehicle, 1 drop 3 times/day for 12 weeks. Efficacy was evaluated as change from baseline to Week 12 of ETDRS letter score and central macular thickness (CMT). The primary analysis used a linear model with baseline ETDRS letters as a covariate, and missing data imputed using multiple imputation pattern mixture model techniques. Active treatment was considered superior to vehicle if the one-sided p-value was <0.15 and the difference in mean change from baseline in ETDRS letters was >0.

RESULTS: Mean CMT showed a greater decrease from baseline with OCS-01 (N = 99) than vehicle (N = 45) at Week 12 (-53.6 vs -16.8 μm, p = 0.0115), with significant differences favouring OCS-01 from Weeks 2 to 12. OCS-01 was well-tolerated, and increased intraocular pressure was the most common adverse event. Mean change in ETDRS letter score from baseline to Week 12 met the p was +2.6 letters with topical OCS-01 and 1 letter with vehicle (p = 0.125). In a post-hoc analysis, there was a greater difference in patients with baseline BCVA ≤65 letters, the OCS-01 group improved 3.8 letters compared with 0.9 letters with vehicle.

CONCLUSION: Topical OCS-01 was significantly more effective than vehicle in improving central macular thickness in patients with DME. Visual improvement was better in eyes with lower baseline vision.