Abstract
Purpose :
In DRCR Retina Network Protocol AC, over 2 years, 70% of eyes in the bevacizumab first group met the protocol-specified criteria for suboptimal response and were switched to aflibercept. The purpose of this analysis is to identify factors for meeting the switching criteria
Methods :
Eyes with center-involved diabetic macular edema (CI-DME) and best corrected E-ETDRS visual acuity (VA) letter score of 69 to 24 (Snellen equivalent 20/50-20/320) were randomized to intravitreous aflibercept (N = 158) or intravitreous bevacizumab (N = 154). Starting from 12 weeks, eyes assigned to bevacizumab were switched to aflibercept treatment if all prespecified criteria for suboptimal response, defined based on VA and central subfield thickness (CST) values, were met after two consecutive injections. In this post hoc secondary analysis, univariable and multivariable Cox regression models were used to evaluate factors at baseline or at 12 weeks associated with time to meeting the switching criteria. Stepwise procedures were used for variable selection to create final multivariable models.
Results :
In the univariable analysis of 16 baseline factors, participants with worse baseline VA and older age had higher risk of meeting the switch criteria; age was the only factor that remained in the final model (hazard ratio [HR] for 10-year increase = 1.32; P = .002). When evaluating eyes at 12 weeks for risk of switching in the future, older age, worse 12-week CST, worse 12-week VA, and less improvement in CST and VA from baseline at 12 weeks were all associated with higher risk of meeting the switching criteria. The final multivariable model included CST at 12 weeks (HR for 10-micron increase = 1.05; P < .001), VA at 12 weeks (HR for 5-letter decrease = 1.10; P = .009) and change in CST at 12 weeks (HR for 10-micron increase = 1.02; P = .03). Based on these three factors, the estimated proportion of eyes switching by 2 years ranged from 39% to 97%.
Conclusions :
The identified risk factors can be used to refine expectations regarding the likelihood that an eye will need to switch to aflibercept when treatment is initiated with bevacizumab. Patients who are older at baseline are more likely to switch. Those with greater CST, worse VA, and less change in CST from baseline at 12 weeks are also more likely to switch in the future.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.