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

Purpose: To 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.

Design: Post hoc analysis of data from a randomized clinical trial.

Participants: Two hundred seventy participants with one or both eyes harboring CI-DME with visual acuity (VA) letter score of 69 to 24 (Snellen equivalent, 20/50-20/320).

Methods: Eligible 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 measures: Meeting 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.

Results: In the group receiving bevacizumab first, older participants showed a higher risk of meeting the switching criteria at any time, with a hazard ratio (HR) for a 10-year increase in age of 1.32 (95% confidence interval [CI], 1.11-1.58). Male participants or eyes with worse baseline VA were more likely to switch at 12 weeks (for male vs. female: odds ratio [OR], 4.84 [95% CI, 1.32-17.81]; 5-letter lower baseline VA: OR, 1.30 [95% CI, 1.03-1.63]). Worse 12-week central subfield thickness (CST; 10-μm greater: HR, 1.06 [95% CI, 1.04-1.07]) was associated with increased risk of switching after 12 weeks. The mean ± standard deviation improvement in visual acuity after completing the switch to aflibercept was 3.7 ± 4.9 letters compared with the day of switching.

Conclusions: The 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 12 weeks, thicker CST was predictive of eyes most likely to be switched in the future.

Financial disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Keywords: Anti-VEGF; DRCR Retina Network; Diabetic macular edema.

Figure 1.

Graph showing the cumulative proportion of eyes switching from bevacizumab to aflibercept at any time by baseline age. Baseline age was grouped based on tertile values. Data from eyes that did not meet the criteria for switching were censored at the last completed visit.

Figure 2.

Graph showing the cumulative proportion of eyes switching from bevacizumab to aflibercept after 12 weeks by 12-week central subfield thickness. Central subfield thickness at the 12-week visit was grouped based on tertile values. Eyes switched at the 12-week visit were not included. Data from eyes that did not meet the criteria for switching were censored at the last completed visit.