First Author: D.Nixon CANADA
Co Author(s): N. Flinn
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To investigate changes from baseline to week 20 in contrast sensitivity (CS), visual acuity (VA), central retinal thickness (CRT) and vision-related quality of life in subjects with recalcitrant diabetic macular edema (DME) switched from long-term ranibizumab treatment to aflibercept.
Tri Med Laser Eye Centre, a private medical clinic in Barrie, Ontario Canada.
In this prospective, IRB approved, investigator masked, single-centre study, 40 non-consecutive DME patients with persistent fluid following at least 3 consecutive ranibizumab injections in the previous 6 months were switched to aflibercept therapy with 5 consecutive monthly loading doses (week 0, 4, 8, 12, and 16). The primary efficacy measure was change from baseline to week 20 in CS measured using the Pelli-Robson Chart. Change from baseline in best-corrected visual acuity (Snellen BCVA), CRT (Heidelberg Spectralis), and National Eye Institute 25-Item Visual Function Questionnaire (NEI VFQ-25) score were recorded.
49 eyes of 40 patients (baseline VA>6/30, median age 71.3 years) with DME were evaluated. A median of 19±11.5 (range 3–52) ranibizumab injections were administered prior to initiation of aflibercept treatment. The median CS increased from 1.40±0.16log units at baseline to 1.50±0.18 at week 20 (p=0.0389), while the median VA was also improved over the study period with logarithm of the minimum angle of resolution [LogMAR] VA 0.24±0.16 at week 20 compared to 0.32±0.17 at baseline (p=0.0034). Median CRT decreased to 265±57µm at week 20 from 293±76µm at baseline, a statistically significant decrease of 28µm (p<0.001). There was an associated relationship between change in CS and change in CRT (p<0.001) while no relationship existed between change in CRT and change in VA (p=0.399). 24 of 40 (60%) patients perceived an overall improvement in NEI VFQ-25 score; 6 patients (15%) perceived no change; 10 patients (25%) perceived a decrease. No adverse events occurred throughout the duration of the trial.
In this study population of recalcitrant DME patients, it was demonstrated that switching from ranibizumab to aflibercept resulted in an improvement in all measured metrics including CS, VA, and CRT. The majority of patients also indicated an improvement in vision related quality of life. There was a statistically significant relationship between a decrease in CRT and an improvement in CS. Although there was an overall improvement in VA there was no relationship between changes in CRT and improvements in VA. This finding of a disconnect between changes in CRT and VA could have implications for present and future studies evaluating treatment patterns and novel drug therapies in this patient population. The inclusion of CS as a measurable endpoint of visual function may yield a more complete understanding of visual outcomes than that obtained using VA measurement alone.