Intraocular Cytokines in Non-responders to Ranibizumab Treatment for Neovascular AMD

Overview

The purpose of this study is to evaluate the level of cytokines (which are small proteins important in cell signalling) in eye fluid (aqueous humour) in patients with wet age related macular degeneration patients who have been treated with an injection in the eye (intravitreal injection) with a drug called ranibizumab. The level of cytokines will be compared between patients who have a good response to ranibizumab treatment and patients who are non-responsive to ranibizumab and need other forms of therapy. This knowledge will help for the future treatment and to potentially develop new medication for wet age-related macular degeneration.

In the treatment of CNV (Choroidal NeoVascularization) secondary from AMD (Age Related Macular Degeneration) by using ranibizumab, patients who are non-responders can be found in approximately 1-10% of treatments. Thus, failure of treatment can lead to loss of vision. Growth factors and cytokines, such as vascular endothelial growth factor (VEGF), pigment epithelium derived factor (PEDF), interleukin 6 (IL-6) and placenta growth factor (PLGF) are known to play an important role in the development of CNV angiogenesis. The rationale for conducting this study to compare VEGF, PEDF, IL-6 and PLGF cytokine levels in the aqueous humor of wet AMD and Polypoidal Choroidal Vasculopathy (PCV) patients who are poor responders to anti VEGF treatment and age-matched "good" responders to anti VEGF. Ranibizumab poor responders in AMD and PCV, who are treated with a combination of PDT/ranibizumab or intravitreous injection of aflibercept (Eyelea®, Regeneron Pharmaceuticals Inc. Tarrytown, NY, USA and Bayer, Basel, Switzerland) will be enrolled to the study. An aqueous humor sample will be obtained when patient receives intravitreal injection treatment and also at 1, 2 months follow up period. VEGF, PEDF,IL-6 and PLGF in aqueous will be analyzed and used to compare between the poor response group and age matched patient with good response to ranibizumab. Age, gender, visual acuity, central macular thickness by OCT, lesion size and fundus autofluorescence data will be collected and used to compare between these groups. Subgroup analysis of different treatment comparison with ranibizumab good responder group will be evaluated. Factors associated with the non-responders of ranibizumab will be analyzed. Non-responders to ranibizumab treatment in AMD may have different levels and responses of inflammatory cytokines compared to the responder group. Understanding the pathogenesis and characteristic of this specific group of patients can help narrow down a specific choice of treatment and prevent the reduction of visual acuity of the patient. This study also helps identify factors associated to poor responders from ranibizumab treatment for wAMD.