Clinical outcome after switching therapy from ranibizumab and/or bevacizumab to aflibercept in Central Retinal Vein Occlusion (CRVO): 1 year results

Abstract

Purpose: After 48 months, unresolved macular edema secondary to central retinal vein occlusion (CRVO) is present in more than half of the patients treated with ranibizumab/bevazicumab. The here presented retrospective, observational clinical study examines, whether switching therapy to aflibercept, improves the clinical outcome in patients with CRVO, who have previously responded insufficiently to ranibizumab/bevacizumab.

Methods: The presented study is a retrospective analysis of CRVO patients (n=13), who initially responded insufficiently to ranibizumab/bevacizumab. Insufficient response was defined as necessity of injections every 6 weeks or more frequently to resolve macular edema. Treatment in these patients was switched to aflibercept, which was administered based on a ‘treat and extend’ regime. The injection interval, relapse-free interval, central retinal thickness, central retinal volume, visual acuity and IOP were evaluated prior to, at month 6 and at month 12 after switching therapy. The statistical analyses were performed using SPSS® Version 20. Since distributions were not normal, non-parametric tests were performed for all analyses. Dependent samples were tested with the exact Wilcoxon signed rank test.

Results: The mean injection interval increased from 1.20 months at baseline to 1.69 months at month 12 after switching therapy to aflibercept (p=0.030). Likewise, the maximal relapse-free interval increased from 4.75 weeks at baseline to 7.63 weeks at month 6 and to 7.68 weeks at month 12 (p=0.011). In accordance to the aforementioned, between baseline and month 12 the mean central retinal thickness decreased by 327.38 µm (p=0.012) and the mean central retinal volume (6 mm diameter) by -2.91 mm³ (p=0.012). Correspondingly, the mean ETDRS score increased from 66.00 at baseline to 76.25 letters at month 12 after switching therapy to aflibercept (+ 10.25 letters, p=0.031). The mean IOP was not statistically significant affected between baseline and month 12 (-1.56 mmHg, p=0.26).

Conclusions: Switching therapy from intravitreal ranibizumab/bevacizumab to aflibercept in insufficiently responding macular edema secondary to CRVO elongates the injection interval and the relapse-free interval. Furthermore, switching therapy to aflibercept provides an improved anatomical as well as functional outcome.