Patients with diabetic macular edema (DME) treated with OCS-01 eye drops (Oculis) demonstrated rapid and sustained improvements in best-corrected visual acuity (BCVA) and retinal thickness in the initial stage of the DIAMOND-1 phase 2/3 trial, Patricio G. Schlottmann, MD, reported at the 2025 European Society of Retina Specialists (Euretina) congress in Paris.
DIAMOND (DIAbetic Macular edema patients ON a Drop) is a 2-stage, double-masked, randomized, multicenter clinical program designed to evaluate the efficacy and safety of OCS-01, which delivers high-concentration dexamethasone (15 mg/ml) to both anterior and posterior segments. Stage 1 involved 148 patients randomized 2:1 to receive either OCS-01 or a vehicle control. Participants underwent a 6-week loading phase with 6 daily doses, followed by a 6-week maintenance phase with 3 daily doses. The primary endpoint was assessed at week 6, with secondary endpoints evaluated at week 12. Stage 2 comprises 2 parallel 52-week phase 3 trials, the second stage of the DIAMOND-1 trial and DIAMOND-2, a trial being conducted in a separate cohort of DME patients to confirm reproducibility of DIAMOND-1 results.
OCS-01 uses a soluble nanotechnology formulation designed to deliver drug to both the anterior and posterior segments of the eye. This approach is intended to overcome limitations that have hindered previous efforts to develop effective topical treatments for DME.
Dr. Schlottmann, a consultant to Oculis, reported that 100 DIAMOND stage 1 patients receiving OCS-01 gained a mean of 7.2 ETDRS letters at week 6, compared with 3.1 letters for 48 vehicle patients (P=.007), with gains maintained through week 12. The proportion of patients achieving ≥15-letter improvement was higher with OCS-01, reaching 25.3% vs 9.8% at week 6 (P=.025) and 27.4% vs 7.5% at week 12 (P=.009). Retinal thickness reductions paralleled visual gains, with mean central retinal thickness decreasing by 71 μm in treatment-naïve eyes and 52.3 μm in previously treated eyes.
Post hoc analyses showed benefits were consistent regardless of prior anti-VEGF treatment or lens status, with treatment-naïve eyes gaining 7.5 letters vs 2.8 with vehicle, and previously treated eyes gaining 6.4 vs 3.6 letters.
OCS-01 was well tolerated, with the most common adverse events including increased intraocular pressure and macular edema. No treatment-related serious adverse events or cataract formation were reported. “OCS-01 met all functional, clinical, and pharmacodynamic endpoints, supporting its potential as a noninvasive option for DME,” concluded Dr. Schlottmann.