title: Aflibercept in branch retinal vein occlusion as second line therapy: clinical outcome 12 months after changing treatment from bevacizumab/ranibizumab-a pilot study.
abstract: OBJECTIVE
  To evaluate the effect of aflibercept (as second line therapy) on the clinical outcome in patients with chronic macular edema secondary to branch retinal vein occlusion (BRVO) insufficiently responding to prior treatment with bevacizumab and/or ranibizumab.
  
  
  METHODS
  Ten eyes of ten patients (n = 10) with chronic macular edema secondary to BRVO were included in a retrospective analysis. These patients received aflibercept after an insufficient response to treatment with ranibizumab and/- or bevacizumab. All intravitreal injections were administered according to a "treat and extend" regimen. Insufficient response was defined as the necessity of injection intervals of 6 weeks or less. The primary outcome of the study was the change in mean injection interval from baseline (prior switching to aflibercept) to month 12 after conversion to aflibercept. Secondary outcomes included the change in best corrected visual acuity (BCVA), central retinal thickness (CRT), central retinal volume (CRV) and intraocular pressure (IOP).
  
  
  RESULTS
  All patients completed 12 months follow-up. In total, patients received a mean of 15.5 injections of ranibizumab and/or bevacizumab over a mean period of 23.1 months prior to switching to aflibercept. The primary endpoint indicated a significant increase in the injection interval from 5.0 weeks at baseline to 8.3 weeks at month 12 (p = 0.002). Secondary outcomes showed favorable results. Mean BCVA increased from 72.7 letters at baseline to 77.9 letters at month 12 after treatment initiation with aflibercept (+5.2 letters, p = 0.375). Correspondingly, CRT values decreased by 61.7 µm (p = 0.344) and the mean CRV (6 mm diameter) by 0.86 mm3(p = 0.021) from baseline to 1 year after treatment initiation with aflibercept. During the treatment period with aflibercept no significant changes in intraocular pressure were registered (p = 0.238).
  
  
  CONCLUSIONS
  Changing treatment to aflibercept in patients with chronic macular edema secondary to BRVO showed a statistically significant extension of the retreatment interval as well as beneficial anatomic changes in our study group. Our data do not allow a definite conclusion since the study was not controlled.
authors.affiliation: Department of Ophthalmology, City Hospital Triemli Zurich, Zurich, Switzerland.
authors.forename: Magdalena A
authors.initials: MA
authors.lastname: Wirth
authors.affiliation: Department of Ophthalmology, City Hospital Triemli Zurich, Zurich, Switzerland ; Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany.
authors.forename: Matthias D
authors.initials: MD
authors.lastname: Becker
authors.affiliation: Graf Biostatistics, Winterthur, Switzerland.
authors.forename: Nicole
authors.initials: N
authors.lastname: Graf
authors.affiliation: Department of Ophthalmology, City Hospital Triemli Zurich, Zurich, Switzerland ; Department of Ophthalmology, University of Zurich, Zurich, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Michels
keywords: Aflibercept; Anti-VEGF; Branch retinal vein occlusion; Macular edema