Switching from ranibizumab/bevacizumab to aflibercept can provide better results in the resolution of persistent and treatment-resistant macular edema secondary to retinal vein occlusion (RVO), according to a literature search and meta-analysis.  

The EMBASE, PubMed and Cochrane databases were independently examined by two reviewers. Baseline characteristics of included studies were patient’s mean age between 57 and 77 years, BCVA from 28.3 to 72.7 ETDRS letters, mean CMT ranging  from 295.00 to 633.67μm and mean number of anti-VEGF injections prior to switching ranging from 4.5 to 17.9, with dosing intervals from 4.8 to 6.8 weeks. Mean study time ranged from 5.2 to 14 months.

Of the thirteen potential studies identified, eight evaluated switching therapy to aflibercept and met the eligibility and inclusion criteria for the meta-analysis in a total of 137 eyes. Reported outcomes as BCVA, CMT and injection intervals were extracted and analyzed.

While no significant changes in BCVA were reported from baseline to month 6, post-switch treatment results showed, at 6 and 12 months respectively, a greater mean increase of 9.62 and 9.08 letters with intervals less than 8 weeks. A lesser increase of 3.43 and 2.09 letters was obtained with intervals wider than 8 weeks.
Pooled data for central macular thickness showed a significant mean reduction of 256.00μm from baseline at 6 months, and 118.00μm at 12 months.  Post-switch eyes showed greater reduction in CMT with mean injection intervals of less than 8 weeks. 

According to the authors, the results of this meta-analysis demonstrated a good rationale for switching  to aflibercept in patients with no response or poor response to other anti-VEGF agents at 6 months, as the different mode of action may aide in the resolution of persistent macular edema. Alfibercept may have superior therapeutic effect over bevacizumab and ranibizumab due to the higher binding affinity with VEGF-A along with a longer half-life and the ability to target a wider range of cytokines, as well as  VEGF-B and PIGF, they noted

As the authors pointed out, this was the first meta-analysis of studies evaluating switching to aflibercept in RVO.

“Given our experience in switching anti-VEGF therapies in nAMD and DME (Chang et al. 2015; Bahrami et al. 2017), the potential benefit of switching therapy in RVO needed to be addressed,” they pointed out. 

References:

Spooner K, Fraser-Bell S, Hong T, Chang A. Effects of Switching to Aflibercept in Treatment Resistant Macular Edema Secondary to Retinal Vein Occlusion. Asia Pac J Ophthalmol (Phila). 2020 Jan 9. doi: 10.1097/01.APO.0000617924.11529.88.

Contact information: Prof Andrew Chang, Sydney Retina Clinic & Day Surgery, Sydney, Australia. Email: achang@sydneyretina.com.au