A Phase 2 Evaluation of Tonabersat for DME

This randomized clinical trial will evaluate the effect of tonabersat compared with placebo on central subfield thickness (CST) in eyes with center-involved diabetic macular edema (CI-DME) and good visual acuity.

Key Inclusion CriteriaAdults with type 1 or 2 diabetes mellitusAt least one eye with:Best corrected E-ETDRS visual acuity letter score ≥ 79 (i.e., 20/25 or better)Ophthalmoscopic evidence of center-involved DME in study eye confirmed by central subfield thickness on spectral domain OCTZeiss Cirrus: ≥ 290 µm in females, ≥ 305 µm in malesHeidelberg Spectralis: ≥ 305 µm in females, ≥ 320 µm in males Recruitment will be monitored with a goal to have equal proportions in the following categories above the CI-DME thresholds: <75 μm, 75 μm to <175 μm, ≥175 μm 3. Media clarity, pupillary dilation, and study participant cooperation sufficient for adequate OCT Key Exclusion CriteriaMacular edema is considered to be due to a cause other than DMEMajor ocular surgery within prior 4 months, or anticipated after randomizationHistory of focal/grid laser or other ocular surgical, intravitreal, or peribulbar treatment for DR or DME within prior 1 year, and no more than 4 prior anti-VEGF injections totalAnticipated need to treat DME or DR during the first 6 months, or anticipated need for cataract surgery during study periodAny history of vitrectomySystemic anti-VEGF or pro-VEGF treatment within 12 months prior to randomizationHistory of chronic renal failure requiring dialysis or kidney transplantHistory of moderate to severe hepatic impairment, including known liver function test (LFT) values > 3x's the upper limit of normal