Can the levels of inflammatory cytokines in the anterior chamber of eyes with diabetic macular edema predict response to therapy?

Abstract

Purpose :
To determine correlation between levels of interleukin 6 & 8 in the anterior chamber (AC) fluid of eyes with diabetic macular edema (DME) and their response to anti-VEGF therapy in the READ-3 study.

Methods : The READ-3 study enrolled 152 eyes with center involving DME. Subjects received monthly intravitreal injections of ranibizumab 0.5mg or 2.0mg. Starting at month 6, eyes received treatment if central sub-filed thickness (CST) >250 µm on TD-OCT and/or fluid was observed within a prespecified area of the macula on SD-OCT. Response to therapy was defined in terms of 1) number of injections received to achieve complete resolution of ME and 2) time to reappearance of ME after initial resolution and cessation of therapy.
Eyes were divided into two groups: (1) Eyes with no resolution of edema throughout the study (Persistent); (2) Eyes with resolution of edema at any time point during the study (Resolved). Both study groups were compared for differences in CST, BCVA, IL-6 and IL-8 levels at BL, ΔBCVA and ΔCST at M12 and M24. Multi-logistic regression was utilized to assess the BL IL-6 and IL-8 levels as predictor of: 1) Edema status (Persistent vs Resolved); 2) Time to resolution of edema in subjects in the resolved group; 3) Mean number of injections needed to achieve edema resolution; 4) Time to rebound after resolution (≤3M vs >3M).

Results : Data from 132 subjects were analyzed while 20 did not meet inclusion criteria for this sub-study. Table outlines the BL BCVA, CST, IL-6 and IL-8 levels between the two study groups. BL CST in the persistent study group was significantly higher than the resolved study group (p<0.05). There was no significant difference between BL AC fluid IL-6 and 8 levels between the groups. Multi-logistic regression analysis did not find BL IL-6 and IL-8 levels to be predictive of 1) ME status; 2) Time to resolution in subjects in the resolved group; 3) Number of injections needed to achieve ME resolution; 4) Time to rebound after resolution.

Conclusions : BL IL-6 and IL-8 levels in the AC fluid are not predictors of the ME outcomes as defined in this study. Subjects with persistent edema have a higher BL CST compared to subjects with resolved of edema.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

Table 1. Comparison of BL CST, BCVA, IL-6 and IL-8 and ΔBCVA and ΔCST at M12 and M24 among the study groups