Correlation of Functional and Structural Outcomes with Serum Antibody Profiles in Patients with Neovascular Age-Related Macular Degeneration Treated with Ranibizumab and Healthy Subjects: A Prospective, Controlled Monocenter Trial

Background: Age-related macular degeneration (AMD) is a multifactorial disorder, and there is growing evidence of immunological involvement in its pathogenesis. To address this, we aimed to identify biomarker candidates related to retinal antigens in patients with neovascular AMD treated with ranibizumab and healthy subjects. Materials and Methods: This study was designed as a prospective, open, parallel-group, interventional, single-center phase IV trial. Fifty subjects with neovascular AMD and twenty healthy volunteers were enrolled. The primary objective was to assess the efficacy of intravitreally (IVT) administered ranibizumab in terms of the change in best-corrected visual acuity in subjects with all subtypes of neovascular AMD and in a subgroup of pretreated AMD subjects. A secondary objective was to assess the efficacy of the same in terms of the change in central retinal thickness (CRT) in the same subjects. Another secondary objective was to identify antibodies against retinal antigens in patients with neovascular AMD treated with ranibizumab and healthy subjects. The last secondary objective was to correlate functional and structural parameters with the identified biomarker candidates to differentiate between initial and deferred responders to IVT administered ranibizumab. Serum was analyzed using customized antigen microarrays containing 58 antigens. Results: After 12 weeks of ranibizumab treatment, treated patients gained 4.02 letters on average. The central retinal thickness (CRT) measured in the complete AMD study population was significantly (p < 0.001) decreased at Week 24 compared to the baseline measurement, and the mean CRT dropped from 393.4 to 296.8 µm. A significant increase in the following autoantibodies was detected between the control group and AMD group at Week 24, as well as in the AMD group between baseline and Week 24: antibodies targeting the proteins serotransferrin, opioid growth factor receptor, 60 kDa chaperonin 2, neurotrophin-4, dermcidin, clusterin and vascular endothelial growth factor. Conclusions: The present trial was able to confirm the efficacy of ranibizumab treatment in neovascular AMD, and treatment-naïve patients benefitted the most. Up- and downregulations of antibodies were observed over the course of treatment with ranibizumab. Some antibodies seemed to have a fair correlation with the classification of initial and deferred responders.