Visual and anatomic outcomes of sustained single agent anti-VEGF treatment versus double anti-VEGF switching in the treatment of persistent diabetic macular edema

Abstract

Background: To compare the anatomical and visual outcomes in eyes with persistent diabetic macular edema (DME) after initial anti-VEGF therapy that were retreated continuously with the same anti-VEGF drug versus those that underwent two successive cycles of medication change in anti-VEGF drugs (double anti-VEGF switch).

Methods: Retrospective review of eyes with persistent DME after 3 initial consecutive monthly anti-VEGF injections. This cohort was divided into two groups: Group 1 continued to receive the same initial anti-VEGF drug for at least 18 months while group 2 eyes were switched to different anti-VEGF medications twice. Group 1 was further subdivided into: Group 1A composed of eyes with less than 20% reduction in central subfield thickness (CRT) at month 3; and group 1B eyes with greater than or equal to 20% reduction in CRT. The percentage of eyes that achieved greater than 10 letters visual acuity (VA) gain or loss was recorded as the primary end point (through month 18 in group 1 and month 6 after 2nd switch in group 2).

Results: Group 1A, 1B and group 2 were composed of 24, 18, and 14 eyes respectively. 34.7%, 56.2% and 36.3% of eyes achieved > 10 letters gain, while 4.3%, 6.2% and 27.2% of eyes lost > 10 letters in groups 1A, 1B, and 2, respectively. Analysis of the visual acuity (VA) letter change in this time interval revealed no significant difference between all groups (p = 0.11). Mean VA and CRT measurements at the primary endpoint in all groups were 0.5, 0.39, and 0.47 logMAR (p = 0.44), and 369.7, 279.9, 321 µm, (p = 0.01) respectively.

Conclusions: There was no difference in the visual outcomes between the two treatment strategies in eyes with persistent DME after 3 consecutive anti-VEGF injections. This may indicate that anti-VEGF switching-even if it is done twice-may have comparable clinical outcomes to sustained treatment with one agent.

Keywords: Anti-VEGF; Diabetic macular edema; Diabetic retinopathy; Intravitreal; OCT.

Fig. 1

Analysis of change in visual acuity through the primary end point between all groups. A diagram illustrating the difference between groups 1A, 1B, and 2 in the amount of visual acuity (VA) letters change at the primary endpoint in comparison to VA at baseline (left), and to transition point (right, P=). There was no significant difference between all groups in both time intervals

Fig. 2

Mean visual acuity measurements in group 1 throughout study. A chart illustrating mean logMAR visual acuity in group1 and subgroups 1A and 1B through 18 months of sustained same agent anti-VEGF treatment. Data were collected at baseline, and after 3, 6, 12 and 18 months. P1 = p value in group 1, P2 = p value in subgroup 1A, P3 = p value in subgroup 1B

Fig. 3

Mean CRT measurements in group 1 throughout study. A chart illustrating mean central retinal thickness (CRT) in group 1 and subgroups 1A and 1B through 18 months of sustained same agent anti-VEGF treatment. P1 = p value in group 1, P2 = p value in subgroup 1A, P3 = p value in subgroup 1B

Fig. 4

Mean visual acuity measurements in group 2 throughout study. Line chart illustrating the logMAR visual acuity in group 2 throughout the study period. All comparisons revealed insignificant changes. Significant improvement in VA was found shortly after 2nd switch before it was rapidly lost

Fig. 5

Mean CRT measurements in group 2 throughout study. Line chart illustrating the mean central retinal thickness in group 2 throughout the study period. Significant improvement was found after the 1st switch and at month 6 after the 2nd switch in comparison to the time of 2nd switching. Significant reduction of CRT was achieved after 1st switch in comparison to baseline and was maintained at month 3 and month 5 after the 2nd switch