Efficacy and Safety Comparison of Ranibizumab and Conbercept Pretreatment Before Vitrectomy in Proliferative Diabetic Retinopathy

Proliferative diabetic retinopathy (PDR) is the most common causes of irreversible blindness in diabetic retinopathy (DR).It is characterized by progressive loss of vision, retinal edema, vitreous hemorrhage (VH), retinal neovascularization, fibrovascular proliferation, tractional retinal detachment (TRD) and neovascular glaucoma (NVG).Although pars plana vitrectomy (PPV) is the cornerstone for treatment of advanced PDR, related postoperative complications such as recurrent VH, NVG, and postoperative fibrovascular proliferation progression may still cause serious visual impairment. It is well known that vascular endothelial growth factor (VEGF) is a leading role of the neovascularization, vascular permeability, and diabetic macular edema.preoperative intravitreal injections of anti-VEGF drugs may represent a new strategy for making vitrectomy safer and more effective for severe PDR.Until now, there are two kinds of anti-VEGF drugs in China, including monoclonal antibodies, like imported drug Ranibizumab, militating by block VEGF-A, and fusion proteins, like domectic drug Conbercept, competitively inhibiting the binding of VEGF with its receptor by blocking multiple targets, VEGF-A, VEGF-B, and placental insulin-like growth factor (PlGF). Studies focusing on the comparison of efficacy between preoperative intravitreal injections of the two drugs for patients with severe PDR undergoing vitrectomy is still limited. Thus, in this study, we aim to carry out a more comprehensive comparison in intraoperative and postoperative aspects on the efficacy and safety between intravitreal ranibizumab injection (IVR) and intravitreal conbercept injection (IVC) before vitrectomy of PDR.