Factors associated with switching intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents in the treatment of neovascular age-related macular degeneration (nAMD)

Abstract

Purpose : To determine the factors associated with doctors’ decisions to switch intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents in the treatment of neovascular age-related macular degeneration (nAMD).

Methods :
In this retrospective study we analyzed the clinical histories of patients undergoing intravitreal anti-VEGF therapy for nAMD between 1st January 2006 and 11th November 2022. These data were collected from 14 clinical practices of 11 retina specialists in Australia, all of whom followed a treat and extend regimen and had full discretion over choice of bevacizumab, ranibizumab or aflibercept and treatment interval.
These data were analyzed with respect to several factors occurring either before or at the point of switch, including initiation drug choice, treating doctor, retinal subspeciality, geographic location of clinical site, treatment interval, and preceding visual loss.

Results : Of the 5731 eyes from 3791 patients treated in this cohort, 1873 were treated with multiple agents. Of these, 1213 had switched from ranibizumab to aflibercept, 236 vice versa, and 424 had other combinations. The percentage of eyes treated with aflibercept rose from 42% at initiation to 64% at the end of the study; ranibizumab fell from 48% to 33%.
All but one of the doctors switched drugs (from 5.2% to 57.5% of eyes). Vitreoretinal surgeons switched four times more often than their medical retinal colleagues. There was a two-fold difference in switch rates between states.
More than two thirds of all switches occurred at intervals of six weeks or less (Figure 1).
For all doctors, there was, at the time of switch, a mean loss of vision from the initial peak gained with treatment of -10.32 letters (SD 10.26), with only one doctor switching whilst the vision was better than baseline and one switching when the vision was 10 letters worse than at baseline.

Conclusions : Switching between agents is common, but the rate at which this occurs varies widely with individual clinicians, their subspecialty and geography. As nearly all physicians had delayed switching until the patient’s vision had declined to or below baseline level, further studies are required to assess whether earlier switching would have resulted in better visual outcomes.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Figure 1. Intervals at which switches occurred

 

Figure 2. Vision metrics at time of switch