A Review of Ranibizumab for the Treatment of Diabetic Retinopathy

INTRODUCTION Laser photocoagulation has been the standard treatment for diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) for several decades. The discovery of vascular endothelial growth factor (VEGF) and the subsequent determination of its critical role in the development DME and PDR has led to the development of VEGF inhibitory drugs. Ranibizumab was the first anti-VEGF drug approved for the treatment of both DME and diabetic retinopathy in eyes with DME. METHODS Medline searches with the keywords "ranibizumab," "diabetic macular edema," and "proliferative diabetic retinopathy" were performed to identify pertinent pre-clinical studies and clinical trials. Top-line data, with emphasis on pivotal trials, was identified and incorporated into this manuscript. Findings from small uncontrolled trials were generally not used unless they filled important gaps in our understanding of anti-VEGF therapy. RESULTS Ranibizumab is a recombinant humanized antibody fragment that binds all isoforms of VEGF-A with high affinity. Three parallel lines of clinical research have produced level I evidence supporting the superiority of ranibizumab over laser photocoagulation for the treatment of DME. Regular injections also lead to improvement in diabetic retinopathy severity scores in a large minority of eyes. Ranibizumab is effective for PDR and produces less visual field loss than laser photocoagulation. It has an excellent safety profile, with low incidence of ocular and systemic adverse events. CONCLUSIONS Ranibizumab has become a frequently used first-line therapy for the treatment of DME. Emerging data suggest that it may become an important treatment for DR and PDR.