Serum levels of vascular endothelial growth factor before and after intravitreal injection of ranibizumab or conbercept for neovascular age-related macular degeneration.

OBJECTIVE:To investigate the serum levels of vascular endothelial growth factor (VEGF) before and after intravitreal injection of conbercept or ranibizumab for neovascular age-related macular degeneration and polypoidal choroidal vasculopathy patients. METHODS:This study is a prospective, interventional case series and involved 28 patients, 18 treated with 0.5 mg of conbercept and 10 treated with 0.5 mg of ranibizumab. Serum concentrations of VEGF were determined by enzyme-linked immunosorbent assay before the injection and at 1 day, 1 week, and 1 month after anti-VEGF treatments. RESULTS:The baseline serum VEGF level of the ranibizumab group was 367.11 ± 311.87 pg/mL, whereas that of the conbercept group was 315.06 ± 170.88 pg/mL (P = 0.653). In the conbercept group, VEGF level significantly decreased to 36.32 ± 72.11 pg/mL at 1 day (P = 0.03) and returned to 136.55 ± 144.62 pg/mL at 1 week (P = 0.03). At 1 month, the concentration increased to 334.48 ± 197.41 pg/mL and showed no significant difference compared with the baseline. In the ranibizumab group, the serum VEGF levels were 292.42 ± 239.80 pg/mL, 282.60 ± 201.36 pg/mL, and 308.83 ± 266.89 pg/mL at 1 day, 1 week, and 1 month after intravitreal injection, respectively. There was no significant difference in the ranibizumab group at each detection time point (P = 0.45). CONCLUSION:Conbercept significantly decreased serum VEGF level 1 day and 1 week after injection, but this effect was not sustained for 1 month. In contrast, ranibizumab had no significant effect on serum VEGF concentration changes. The reduction in serum VEGF by conbercept may affect its systemic safety profile.