Defining "strong" Versus "weak" Response to Antivascular Endothelial Growth Factor Treatment for Center-Involved Diabetic Macular Edema

Background/Purpose:To define "strong" versus "weak" antivascular endothelial growth factor (anti-VEGF) treatment response in eyes with center-involved diabetic macular edema (CI-DME).Methods:Exploratory analyses of three DRCR Retina Network randomized trials of eyes with CI-DME treated with aflibercept, bevacizumab, or ranibizumab. Thresholds of 5-, 10-, and 15-letter gain defined strong visual acuity (VA) response when baseline VA was 20/25-20/32, 20/40-20/63, or 20/80-20/320, respectively. Thresholds of 50, 100, or 200-µm reduction defined strong anatomical response when baseline central subfield thickness (CST) was <75, ≥75 to <175, or ≥175-µm above standard thresholds. Additional thresholds from regression equations were calculated.Results:At 24 weeks, outcomes for strong response were achieved by 476 of 958 eyes (50%) for VA and 505 eyes (53%) for CST. At 104 weeks among the 32% of eyes with strong VA and CST response at 24 weeks, 195 of 281 (69%) maintained strong VA and CST response, whereas 20 (7%) had neither strong VA nor strong CST response. Outcomes rates were similar across protocols and when defined using regression equations.Conclusion:These phenotypes are suitable for efforts to identify predictive biomarkers for response to anti-VEGF therapy for DME and might facilitate comparison of treatment response among diverse cohorts with DME.