Do published trial results influence physician prescribing patterns? Intravitreal antivascular endothelial growth factor usage by the United States Ophthalmologists before and after Protocol T study.

Abstract

Clinical trial publications may influence physician prescribing patterns. The Diabetic Retinopathy Clinical Research Network (DRCR.net) Protocol T study, published in 2015, examined outcomes of intravitreal antivascular endothelial growth factor (VEGF) medications for treatment of diabetic macular oedema (DME). This study investigates if the Protocol T 1-year results were associated with changes in prescribing patterns. Anti-VEGF agents have revolutionized treatment of DME by blocking angiogenesis signalled by VEGF. Three commonly used anti-VEGF agents are on-label aflibercept (Eylea, Regeneron) and ranibizumab (Lucentis, Genentech) and off-label bevacizumab (Avastin, Genentech). From 2013 to 2018, there was a significant positive trend in the average number of aflibercept injections for any indication ( P < 0.002). There was no significant trend in the average number of bevacizumab ( P = 0.09) and ranibizumab ( P = 0.43) for any indication. The mean proportion of aflibercept injections per provider per year was 0.181, 0.217, 0.311, 0.403, 0.419 and 0.427; each year-by-year comparison was significant (all P < 0.001), and the largest increase was in 2015, the year of publication of Protocol T 1-year results. These results imply and reinforce that clinical trial publications may have significant effects on ophthalmologist prescribing patterns.