Aqueous humor mediator levels as biomarkers of anti-VEGF response in age-related macular degeneration.

PURPOSE

To monitor intraocular mediator dynamics in treatment-naïve neovascular age-related macular degeneration (nAMD) patients treated with anti-VEGF intravitreal injections (IVIs) to identify individual mediator patterns correlating with treatment response.

DESIGN

Interventional, monocentric, prospective, clinical study.

PARTICIPANTS

Treatment-naïve nAMD patients.

METHODS

Aqueous humor samples (100-200 μL) were collected by clear cornea paracentesis at baseline (before the first anti-VEGF IVI) and before the second and third anti-VEGF IVIs. The levels of 13 intraocular mediators were measured (VEGF-A, VEGF-C, PlGF, IL-1β, IL-6, IL-10, IL-18, CXCL1, CXCL5, CXCL7, CXCL8, MIP-1α and TNFα) using multiplex arrays.

MAIN OUTCOMES MEASURES

The primary endpoint was the changes in intraocular inflammatory mediator levels between baseline and month 3. Secondary endpoints were the changes in best-corrected visual acuity (BCVA) and Central Retinal Thickness (CRT) between baseline and month 4.

RESULTS

Fifteen eyes were included in the study. BCVA remained stable throughout the study (p = 0.07). CRT, foveal thickness, and the presence of intraretinal and subretinal fluid significantly decreased after anti-VEGF IVIs (p < 0.0001, p < 0.0001, p < 0.001 and p < 0.001, respectively). After anti-VEGF IVIs, VEGF-A levels significantly decreased (p < 0.0001). No significant differences in all other mediator levels were observed. Three patients had baseline VEGF-A levels ≤50 pg/mL: they showed higher baseline IL-6 levels (p = 0.05), and elevated IL-6 (p = 0.03), PlGF (p = 0.02), VEGF-C (p = 0.005), IL-8 (p = 0.04), and TNFα (p = 0.013) levels after the first IVI. Good clinical responders had significantly higher baseline VEGF-A levels (p = 0.007). Patients who required a fourth IVI within 8 weeks of the loading dose had higher baseline TNFα levels (p = 0.05); higher MIP-1α levels after the first IVI (p = 0.045); and elevated TNFα (p = 0.026) and IL-8 (p = 0.029) levels after the second IVI.

CONCLUSIONS

The aqueous humor levels of the studied mediators remained stable after anti-VEGF IVIs, except for a significant decrease in VEGF-A levels in all patients. Patients with low baseline intraocular VEGF-A levels (i.e., ≤50 pg/mL) showed an intraocular inflammatory profile with elevated IL-6, PlGF, VEGF-C, IL-8 and TNFα levels. Treatment response correlated with high baseline VEGF-A levels. An interval > 8 weeks between the third and fourth anti-VEGF IVIs was associated with a pro-angiogenic/pro-inflammatory environment.