A systematic review to assess the 'treat-and-extend' dosing regimen for neovascular age-related macular degeneration using ranibizumab.

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the developed world. Monthly or as-needed (PRN) dosing strategies of intravitreal ranibizumab have been established as efficacious treatment options for neovascular AMD. More recently, the 'treat-and-extend' dosing regimen (TREX) is being adopted in clinical practice as it represents a patient-centric and economical option, reducing treatment burden by extending injection intervals when possible. However, the efficacy of TREX using ranibizumab monotherapy remains to be defined. Therefore, we performed a systematic review to assess the current evidence for TREX using ranibizumab by searching MEDLINE, Embase and PubMed. Of the 1733 articles identified, nine TREX studies were included in our analysis (n=748 eyes). Average patient age was 79.25 (range: 77.34-82.00; SD: 7.27). Baseline BCVA ranged from 48.5-68.9 ETDRS letters. BCVA improvement was 8.92 letters at 1 year (range: 6.5-11.5; SD: 7.54), as a weighted mean accounting for numbers of study eyes. The weighted mean number of injections at one year was 8.60 (range: 7.3-12.0; SD: 1.73). Previously, the landmark ANCHOR and MARINA trials reported gains of 11.3 and 7.2 letters, respectively, using monthly ranibizumab. Chin-Yee et al reported a gain of 3.5 ETDRS letters with 5.3 (S.D. 0.66) PRN ranibizumab injections as weighted means at 1 year in their recent systematic review. Our analysis suggests that TREX delivers visual outcomes superior to PRN and approaches similar efficacy to monthly injections. Further RCTs are needed to fully evaluate the efficacy and economy of TREX in the long-term.