Using visual acuity to guide diabetic macular oedema treatment

Diabetic macular oedema (DME) patients with visual acuity (VA) of 20/50 or worse are likely to experience superior clinically relevant VA outcomes at 1 year and over 2 years using aflibercept vs bevacizumab or ranibizumab, according to an analysis of Diabetic Retinopathy Clinical Research (DRCR) Network’s Protocol T data presented at the 38^th Asia-Pacific Academy of Ophthalmology (APAO 2023) Congress.

“Treating DME should be considered when central subfield thickness [CST] reaches ≥300 μm, at which point management should only depend on VA,” stated presented Professor Neil Bressler of the Johns Hopkins Wilmer Eye Institute in Baltimore, Maryland, US. “As Protocol T demonstrated, on average, visual gains among patients with VA of 20/32–20/40 are comparable between aflibercept, bevacizumab and ranibizumab at 2 years [mean change in VA letter score: +7.8, +6.8, and +8.6, respectively]. However, in cases of VA of 20/50 or worse, on average, visual gains were greater with aflibercept vs bevacizumab or ranibizumab at 1 year, and vs bevacizumab at 2 years [p=0.02] [mean change in VA letter score at 2 years, aflibercept: +18.1, bevacizumab: +13.3, ranibizumab: +16.1].” [Bressler N, APAO 2023]

“Although aflibercept is superior to ranibizumab at 1 year but not at 2 years, it is still recommended to start treatment with aflibercept, as outcomes in the aflibercept group were superior to the ranibizumab group’s when averaged over the course of 2 years in patients with VA of 20/50 or worse,” advised Bressler. The mean gain in VA over 2 years was 4.5 letters more with aflibercept vs bevacizumab (p<0.001) and 3.4 letters more with aflibercept vs ranibizumab (p=0.009). [Curr Opin Ophthalmol 2017;28:636-643]

To ascertain that the mean changes in VA were clinically relevant to individual patients, the investigators assessed ≥15 letter improvement at 1 year, which translates to VA doubling in patients with VA of 20/50 or worse at baseline. At 1 year, the proportion of patients attaining ≥15 letter improvement was 67 percent, 41 percent, and 50 percent in the aflibercept, bevacizumab, and ranibizumab groups, respectively. “While this clinically relevant improvement is not different between aflibercept, bevacizumab, and ranibizumab at 2 years, we would still recommend starting treatment with aflibercept. This is because looking over 2 years, the amount of time spent with ≥15 letter improvement is greater with aflibercept vs bevacizumab [p=0.02] and with aflibercept vs ranibizumab [p=0.05],” noted Bressler.

The objective of anti-VEGF treatment for DME is to maximize VA while minimizing the number of injections. DRCR Network recommends that anti-VEGF treatment starts with six monthly injections, unless VA of 20/20 and CST ≤300 μm are achieved sooner, after which point injections should be withheld if both VA and CST remain stable. “The recommendation for six initial monthly injections of aflibercept stems from the Protocol T finding that after only three initial injections, approximately half of the eyes will have a CST ≤300 μm, and after three more monthly injections, this proportion increases to almost 70 percent. In addition, after the first three doses, the average gain in VA is equivalent to +10 letters, and it increases further to +13 letters with three additional doses,” explained Bressler. “However, after the initial six injections, there is no difference between continued treatment with aflibercept and observation with as-needed rescuing with aflibercept [in case of VA or CST changes], except for fewer injections with the latter strategy.”