Risk Factors for Meeting Criteria for Switching from Bevacizumab to Aflibercept When Treating Eyes with Diabetic Macular Edema and Visual Acuity of < 20/40

Abstract

ObjectiveTo identify factors for meeting prespecified criteria for switching from bevacizumab to aflibercept in eyes with center-involved diabetic macular edema (CI-DME) and moderate vision loss initially treated with bevacizumab in DRCR Retina Network Protocol AC. DesignPost hoc analysis of data from a randomized clinical trial Participants270 participants with one or both eyes with CI-DME and visual acuity (VA) letter score of 69 to 24 (Snellen equivalent 20/50-20/320) MethodsEligible eyes were assigned to receive intravitreal aflibercept monotherapy (N=158) or bevacizumab followed by aflibercept if prespecified criteria for switching were met between 12 weeks and 2 years (N=154). Main Outcome MeasuresMeeting switching criteria: 1) at any time, 2) at 12 weeks, and 3) after 12 weeks. Associations between meeting the criteria for switching and factors measured at baseline and 12 weeks were evaluated in univariable analyses. Stepwise procedures were used to select variables for multivariable models. ResultsIn the bevacizumab first group, older participants had higher risk of meeting the switching criteria at any time, with a hazard ratio (HR) for a 10-year increase in age (95% confidence interval) of 1.32 (1.11 – 1.58). Male participants or eyes with worse baseline VA were more likely to switch at 12 weeks (HR for male vs. female = 4.84 [1.32 – 17.81]; HR for 5-letter lower baseline VA: 1.30 [1.03 – 1.63]). Worse 12-week CST (HR for 10-μm greater = 1.06 [1.04 – 1.07]) was associated with increased risk for switching after 12 weeks. The mean (SD) improvement after completing the switch to aflibercept was 3.7 (4.9) letters. ConclusionsThe identified factors can be used to refine expectations regarding the likelihood that an eye will meet protocol criteria to switch to aflibercept when treatment is initiated with bevacizumab. Older patients are more likely to be switched. At twelve weeks, thicker central subfield thickness was predictive of eyes most likely to be switched in the future.