Aims To provide data on plasma vascular endothelial growth factor (VEGF) concentration during three consecutive monthly intravitreal aflibercept injections and after transition to bimonthly treatment in patients with neovascular age-related macular degeneration (nAMD).

Methods Sixteen consecutive treatment-naïve Caucasian patients with nAMD were included in the study. The treatment consisted of one intravitreal aflibercept (2 mg) injection every 28 days for three consecutive months followed by a fourth injection 8 weeks later. VEGF plasma concentrations were measured with Luminex on day 0 (baseline, prior to first injection); days 1, 6 and 27 (prior to second injection); day 55 (prior to third injection) and days 97 and 111 (after third injection).

Results Baseline plasma VEGF concentration was 59.6±13.3 pg/mL. Aflibercept decreased plasma VEGF concentration to 32.5±3 pg/mL on day 1 (p<0.0001) and 34.7±6.3 pg/mL on day 6 (p<0.0001). On day 27, the VEGF plasma level increased to 50.6±6.5 pg/mL (p=0.009) and on day 55 to 52.8±8.8 pg/mL (p=0.027). There was no statistically significant difference between mean plasma VEGF concentrations on days 27 and 55 (p=0.139). Plasma VEGF concentration recovered completely 6 weeks after the third injection, reaching 57.9±9.6 pg/mL on day 97 (p=0.600) and 59.5±11.6 pg/mL on day 111 (p=0.987).

Conclusions Intravitreal aflibercept decreases plasma VEGF concentration mostly in the first week after treatment. Despite repeated monthly intravitreal injections, there was a monthly increase in plasma VEGF values to near baseline levels, with complete recovery 6 weeks after the third injection.

Trial registration number Identifier no. NCT02125864.