TITLE:
Aqueous Interleukin-6 (IL-6) Level Is a Marker for Treatment Resistance to Bevacizumab in Age-Related Macular Degeneration —Aqueous Cytokines after Bevacizumab
AUTHORS:
Kakarla V. Chalam, Sandeep Grover, Sankarathi Balaiya, Ravi K. Murthy
KEYWORDS:
VEGF; Interleukin-6; AMD; Bevacizumab; Aqueous; Bead Based Assay
JOURNAL NAME:
Open Journal of Ophthalmology,
Vol.4 No.1,
February
13,
2014
ABSTRACT:
Background: To prospectively evaluate the effect of intravitreal bevacizumab on
aqueous levels of interleukin-6 (IL-6) and vascular endothelial growth factor
(VEGF) in patients with exudative age-related macular degeneration (AMD) and to correlate clinical outcomes of patients and aqueous
cytokine levels before and after injection. Methods: The study group consisted of 30 eyes from 30 patients
with exudative AMD who underwent intravitreal injection
of bevacizumab three times at monthly intervals. The aqueous samples prior to
the 1st injection (baseline) and 3rd injection were analyzed for VEGF and IL-6
levels, evaluating the effect of 2 doses of intravitreal bevacizumab. Study patients were sub-grouped based upon change in
central subfield (CSF) macular thickness on SD-OCT, at 8 weeks. Group 1
included patients (n = 14) with a
decrease in CSF thickness greater than 10% from the baseline and were
categorized to have “improved”. Group 2 included patients (n = 16) who had a decrease in CSF thickness 10% or less and were considered “treatment-resistant”. Results: There was no statistically significant change in aqueous
VEGF and IL-6 levels after intravitreal bevacizumab. In sub-group analysis, in
both Groups 1 and 2 patients, aqueous IL-6 levels showed a better correlation
with CSF thickness on SD-OCT (r = 0.72 and 0.71,
respectively). Conclusions: Data
from our study suggest that aqueous IL-6 may be an important marker of
treatment response or resistance. Future therapeutic strategies may include
targeted treatment against both VEGF and IL-6, in patients who do not respond
to anti-VEGF treatment alone.