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Which DRCR.net protocol has had the biggest impact on your practice?
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Protocol I
If I had to pick only one study that has had the biggest impact on my current practice among the many important multicenter randomized clinical trials carried out by DRCR.net, it would be Protocol I. At the time of study, anti-VEGF agents were being used mostly for age-related macular degeneration, and focal/grid laser treatment was the standard of care for management of diabetic macular edema. In addition, small studies suggested that intravitreal steroids may be beneficial for DME.
Protocol I showed clearly that intravitreal injections of anti-VEGF with prompt or deferred laser treatment achieved superior visual acuity outcomes compared with laser alone or steroid with prompt laser. In addition, the anti-VEGF groups were followed for 5 years, giving us an opportunity to study long-term safety and efficacy outcomes. It showed that the visual acuity benefit from anti-VEGF for DME was maintained despite needing fewer intravitreal injections over time with very few ocular side effects. Thus, Protocol I has helped to establish anti-VEGF therapy as the first-line treatment for center-involved DME; as a result, I am doing less focal/grid lasers now and use intravitreal steroids as a second-line treatment in most cases. In my opinion, this study had a profound impact on how most of us are currently treating patients with DME.
If I can mention a few other studies of note, they would be Protocol T, Protocol S and the genetics study. Protocol T helped to fine-tune which of the three anti-VEGF agents (aflibercept, bevacizumab and ranibizumab) would be beneficial for patients with DME based on baseline visual acuity and possibly retinal thickness. The 2-year data from Protocol S showed that anti-VEGF therapy is not inferior to panretinal photocoagulation, which has been the standard of care for proliferative diabetic retinopathy (PDR) for many decades. I look forward to the long-term outcomes from this study to see whether the benefit from anti-VEGF is maintained for PDR. Finally, the genetics study that is currently ongoing will help to gain many more insights into our understanding of diabetic retinopathy and treatment responses.
Judy E. Kim, MD, is an OSN Retina/Vitreous Board Member. Disclosure: Kim reports she is a vice chair of DRCR.net.
Protocol S
The DRCR.net protocol that has had the biggest impact in my practice is Protocol S, comparing panretinal photocoagulation (PRP) vs. intravitreous ranibizumab for proliferative diabetic retinopathy (PDR). PRP has been the standard treatment for PDR for the past 40 years since the Diabetic Retinopathy Study showed its beneficial effect.
Until Protocol S, the vast majority of retina specialists would treat PDR exclusively with PRP, an effective treatment but with drawbacks; it causes permanent peripheral visual field loss, decreases night vision, can exacerbate DME, takes days to weeks to have an effect on the neovascularization, is patient dependent, and needs clear media to be completed. All of these observations have made alternative treatments desirable. Protocol S has revolutionized the management approach of PDR in my practice.
Protocol S showed that ranibizumab was equal to PRP as an effective treatment of PDR and seems to have some advantages compared with PRP because less diabetic macular edema occurred and need for surgery with vitrectomy was decreased. This protocol has provided the evidence for the use of ranibizumab as a valuable tool to treat this vision-threatening complication of diabetic retinopathy, especially in patients with DME, patients who cannot tolerate full PRP or patients in which the view is not sufficient for PRP due to cataract or some degree of vitreous hemorrhage. PRP remains a useful tool in long-term management especially in patients with non-compliance or with significant traction.
Treatment with ranibizumab has enabled us for the first time to effectively, easily and quickly stop the active process of PDR and halt more vitreous bleeding or progression of neovascularization in these patients that full PRP is not feasible in a timely fashion in addition to the other potential advantages that were seen when compared with full PRP.
Dimitra Skondra, MD, PhD, is an assistant professor of ophthalmology and visual science and director of the J. Terry Ernest Ocular Imaging Center, University of Chicago. Disclosure: Skondra reports no relevant financial disclosures.