The treat-and-extend injection regimen versus alternate dosing strategies in age-related macular degeneration: a systematic review and meta-analysis.

PURPOSE: To assess outcomes of the treat-and-extend (T&E) injection regimen for neovascular age related macular degeneration (AMD) as compared to either a monthly or a pro-re-nata (PRN) treatment strategy. DESIGN: Systematic review and meta-analysis METHODS: Studies that compared the T&E regimen with either monthly or PRN dosing for treatment-naïve AMD were included. Trial eligibility, data extraction and risk of bias were assessed according to Cochrane review methods. Estimates were pooled using random effects meta-analysis. RESULTS: Four eligible studies were identified, all using ranibizumab (total n=940 eyes), including two randomized controlled trials comparing T&E to monthly and two retrospective reviews comparing T&E to PRN. No studies evaluating aflibercept were identified. Improvements in vision and central retinal thickness were similar between T&E and monthly at 12 months, with a mean difference of -1.79 letters (95% CI: 3.70, 0.13) and 3.76μm (95% CI: -13.78, 21.30) in favour of monthly injections. In contrast, visual gains were higher in the T&E compared to PRN group (difference of +6.18 letters, 95% CI: 3.28, 9.08). Fewer injections were required using the T&E regimen when compared to monthly (mean of -1.6 and -6.9 injections less at 12 and 24 months respectively). A mean of 1.44 more injections was required for the T&E compared to PRN regimen at 12 months, however this was achieved with fewer visits. CONCLUSION: Despite the growing preference for the T&E regimen, there is limited head-to-head evidence comparing dosing strategies. The evidence available however, suggests that at 12 months, T&E is comparable to monthly and superior to PRN dosing for both efficacy and safety outcomes when using ranibizumab.