Background: Vitreous concentration of vascular endothelial growth factor (VEGF) rises significantly during proliferative diabetic retinopathy (PDR). Bevacizumab (Avastin) is a humanized monoclonal antibody to VEGF. Intravitreal administration of bevacizumab (IVB) has recently been shown to be effective in some ocular neovascularizations, including PDR. In this study we evaluate the efficacy of IVB in eyes with active, progressive PDR.
Methods: In an interventional prospective case series, eyes with active, progressive PDR underwent one to three IVB injections (1.25 mg) at intervals of either 6 or 12 weeks. Complete ophthalmic examinations and color fundus photography were performed at baseline and 1, 6, 12, and 20 weeks after the first injection. Fluorescein angiography (FA) was performed before injection and 20 weeks after. The primary outcome measures were clearing of vitreous hemorrhage (VH) and regression of active fibrovascular tissue (FVT). The secondary outcomes were any change in best-corrected visual acuity (BCVA) and any incidence of adverse events.
Results: Thirty eight eyes of 38 patients with a mean age of 54.7 +/- 10.1 years were included in the study. VH resolved significantly after 1 week (P = 0.014), 12 weeks (P = 0.0001), and 20 weeks (P = 0.002). The vascular component of FVT regressed, though the FVT area did not change. Mean BCVA improved significantly compared to baseline at all follow-up examinations. Two cases showing moderate fibrous proliferation developed traction retinal detachment (TRD).
Conclusions: IVB has significant therapeutic effect on eyes with active, progressive PDR: the treatment causes a significant amount of VH resolution and neovessel regression. At the same time, this procedure may increase the risk of TRD in eyes with fibrous proliferation.