Collaborative clinical research by clinicians based in Tel Aviv University, Israel, University of Buenos Aires, Argentina, the University of Leipzig, Germany and the University of Milan, Italy have shown that certain SD-OCT biomarkers may act as useful image findings pointers in DEX treatment of diabetic macular edema (DME). The research, carried out on a total of 299 eyes from 284 patients treated with DEX implant for DME, showed a correlation between specific metabolic biomarkers and successful DEX implant treatment. The results of the study demonstrated that among eyes with DME, those with sub-macular fluid, no hyper-reflective foci (HRF), and a continuous IS-OS layer appeared to respond better to DEX implants than those without such features.
A significant number of DME patients are known not to respond to first line anti-VEGF treatment. However, such patients have been shown to have improved visual acuity (VA) and to have a decrease in retinal thickness with the use of dexamethasone (DEX) intravitreal implant 0.7 mg (Ozurdex), presumably due in part to the fact that corticosteroids target different pathways in the pathogenesis of DME to those targeted by anti-VEGF treatments. Previous research has shown that certain anatomical features, such as evaluation of individual tissue layers, measurement of retinal thickness and macular volume, and the distribution and existence of hyper-reflective foci can predict treatment success or failure. The international research collaboration sought to assess if changes detectable using SD-OCT might help to predict successful DEX implant treatment in both naïve and refractory subjects.
Results of the study showed that the presence of sub-retinal fluid (odds ratio [OR], 1.98; 95% confidence interval [CI], 1.23 – 3.20; P=0.01), the absence of HRF (OR, 3.66; 95% CI, 1.40 – 9.62; P=0.01), and integrity of the IS-OS layer (OR, 2.09; 95% CI, 1.30 – 3.37; P=0.003) all appeared to be predictive of a better visual outcome following treatment with DEX implants. The study showed that eyes with naïve DME gained more vision than refractory eyes (P<0.001) and that the predictive value of the OCT findings did not appear to differ according to the classification of naïve vs. refractory. The research found that 209 DME eyes (70%) were naïve while 90 cases (30%) were refractory to previous anti-VEGF injections. In concluding their study the researchers stated that, “this series demonstrates that certain biomarkers can help predict the response to DEX implant in DME. Future prospective investigations should consider imaging and systemic biomarkers, and compare anti-VEGF drugs with DEX implants in a head-to-head trial aimed to tailor and optimize patient care.”