Dexamethasone eye drops show therapeutic potential in diabetic macular edema
Topical OCS-01, a dexamethasone ophthalmic suspension, appears to be beneficial in the treatment of patients with diabetic macular edema (DME), with the results of a phase II study showing that the drug helps improve central macular thickness.
The phase II study included patients aged 18–85 years with DME of <3 years duration, Early Treatment Diabetic Retinopathy Study (ETDRS) central subfield thickness ≥310 μm by spectral domain optical coherence tomography (SD-OCT), and ETDRS letter score ≤73 and ≥24 in the study eye. These patients were randomized to treatment with OCS-01 (n=99) or matching vehicle (n=45), one drop three times daily for 12 weeks.
Researchers assessed the change from baseline in ETDRS letter score and central macular thickness (CMT), the primary efficacy outcomes. They used a linear model with baseline ETDRS letters as a covariate, and missing data imputed using multiple imputation pattern mixture model techniques.
At week 12, mean CMT showed a much greater decrease with OCS-01 than with vehicle (−53.6 vs −16.8 μm; p=0.0115). The superiority of OCS-01 was already evident at week 2 and maintained through week 12.
Meanwhile, while more patients in the OCS-01 group gained ≥10 or ≥15 ETDRS letters (14 percent and 5 percent, respectively) than in the vehicle group (9 percent and zero, respectively), the between-group differences were not statistically significant. Furthermore, the proportion of patients losing ≥15 ETDRS letters did not differ between the two groups (zero in the active treatment group vs 2 percent in the vehicle group).
In terms of safety, OCS-01 was well-tolerated, with intraocular pressure elevations being the most common adverse event. 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.