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Advances in DME Treatment

Observing the AUC and Treating Early

As the prevalence of diabetic retinopathy (DR) increases in Asia-Pacific countries, so has the proportion of patients with severe visual loss or blindness. For patients with diabetes, the loss of sight is one of the most concerning complications. So, when clinical results from the VIVID and VISTA studies show five-letter visual gains, it offers doctors and patients a promising avenue to mitigate this growing threat. 

Some of these therapies for DR were discussed during the recent Asia-Pacific Academy of Ophthalmology (APAO) Congress, in a symposium titled ‘Advances in DME Treatment’. 

According to Dr. Paisan Ruamviboonsuk, who chaired the session, one strategy for determining a treatment’s long-term efficacy is by observing the area under the curve 

(AUC). He said this is important because it provides key insights into the day-to-day visual experiences of patients over time, rather than only examining letter gains or losses at pre-specified time points during clinical studies. By monitoring AUC, physicians can also catch disease progression and treat early (with aflibercept, for example) – and thus, reduce the amount of time patients experience poor vision, while increasing the opportunity for meaningful final vision gains.

Early and intensive treatment with aflibercept was also explored, with data from the VIVID and VISTA studies showed rapid and increasing visual acuity (VA) gains at year one. These results were relayed by Dr. Voraporn Chaikitmongkol, assistant professor of ophthalmology at Chiang Mai University, Thailand. Investigators found that at 52-weeks, patients who received aflibercept gained ≥10 letters from baseline – and these improvements could be sustained for three years. 

Another study covered by Dr. Chaikitmongkol was the DRCR.net Protocol T, which compared the efficacy of different anti-VEGF agents for visual impairment due to DME. This study also showed how early, intensive treatment in the first year can make a significant reduction in the treatment burden thereafter. In examining the differences between anti-VEGF agents, Protocol T results show that at week 52, patients treated with aflibercept gained more letters than those treated with bevacizumab and ranibizumab. Meanwhile, post-hoc analysis of the Protocol T study showed that lower HbA1c, younger age and patients with no history of pan retinal photocoagulation (PRP) are associated with better 2-year visual outcomes.

Dr. Chaikitmongkol also noted that emerging data from real-world studies like APOLLON are also showing good visual gains with aflibercept in DME management, with improvements of approximately 8 letters after 6 months of treatment.

Dr. Neil Bressler, a professor from Johns Hopkins University’s School of Medicine, USA, discussed another real-world study – Protocol V, a randomized, multi-center clinical trial. He presented results from the trial and again mentioned the important of the AUC. He also asked the gathered crowd: “Does it matter which anti-VEGF drug you use?” In his answer, he says that sometimes it matters, and sometimes it doesn’t. To explain, he pointed to a subgroup in Protocol V, which could have contributed to the differences in the trial’s results: In this subgroup, patients with a VA or 20/50 or worse (which was half the subgroup driving the overall results), were the ones who experienced the most superior visual outcomes with aflibercept over two years, compared with those using other agents. However, for those with VA of 20/30 or 20/40, the results comparing the three anti-VEGF agents weren’t as pronounced. Thus, aflibercept seems clinically effective for patients with lower VA.

Dr. Bressler also discussed how they calculated the AUC: Investigators took each subject’s AUC and looked at the change in baseline VA, plotted out against the x-axis of weeks. The AUC for each subject was then calculated by approximating the sum of a series of geometric figures seen on the graph. 

He also mentioned the study showed the subjects’ vision remained stable even after 6 months in both VA gained and actual VA, showing little loss of vision – even if the edema persisted beyond two years. Dr. Bressler concluded his session by saying that “the regimen does lead to a reduced number of infections,” adding that those interested could access the slides and studies on this topic at DRCR.net. 

Editor’s Note: A version of this article first appeared in APAO 2019 Show Dailies Day 3 issue published at APAO 2019 Congress in Bangkok, Thailand (page 4). The APAO Show Daily is the official conference news of Asia-Pacific Academy of Ophthalmology congress, published by PIE and CAKE Magazines. Reporting for this story also took place at APAO 2019 Bangkok, where Media MICE was the Official Media Partner.

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