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DRCR.net has great impact on understanding, treatment of diabetes-related eye disease
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I have previously written several commentaries on the topic of diabetes, diabetic retinopathy and diabetic macular edema. Rather than repeating these comments, I would like to share some thoughts on the source of much of my information, the Diabetic Retinopathy Clinical Research Network. DRCR.net is a collaborative network created to facilitate multicenter clinical research into diabetes-associated eye disease, including DR and DME, cataract, glaucoma, vitreous hemorrhage and other conditions associated with diabetes. This network, funded by the National Eye Institute, has contributed greatly to our understanding and treatment of eye disease associated with diabetes.
The DRCR.net was established in September 2002 and is a fantastic example of public-private collaboration. The clinician network currently includes more than 115 participating private practice and academic medical center sites with more than 400 committed vitreoretinal specialist ophthalmologists. The network also collaborates constructively with industry, evaluating the comparative safety and efficacy of drugs and devices. Any retina specialist who qualifies can participate and also submit a protocol idea. The network chair is Lee M. Jampol, MD, of Northwestern University Feinberg School of Medicine. The Coordinating Center is based at the Jaeb Center for Health Research in Tampa, Florida, and directed by Adam R. Glassman, MS, and Roy W. Beck, MD, PhD. The NEI Project Officer is Eleanor Schron, PhD, RN.
The knowledge gained from the multiple clinical trials supported by DRCR.net is nothing short of amazing and has transformed the clinical treatment of DR and DME worldwide. The number of protocols completed and ongoing (more than 30) are too many to list but include well-designed and well-conducted clinical trials evaluating laser, triamcinolone, topical NSAIDs and all three commercially available anti-VEGF injectables in the treatment of DR and DME as well as vitreous hemorrhage. In addition, clinical trials into the proper management of patients with diabetic eye disease about to undergo cataract surgery have been very instructive.
At least six clinical trials are ongoing at this time, and many others are in the planning stage. A few of the critical learnings regarding DME include the Protocol B finding that focal/grid photocoagulation is more effective and has fewer side effects than 1 mg or 4 mg doses of intravitreal triamcinolone; the Protocol E finding that in cases of DME with good visual acuity, peribulbar triamcinolone, with or without focal photocoagulation, is unlikely to be of substantial benefit; the Protocol H finding that intravitreal bevacizumab can reduce DME in some eyes; the Protocol I finding that intravitreal ranibizumab with prompt or deferred focal/grid laser photocoagulation is more effective through 2 years in increasing visual acuity compared with focal/grid photocoagulation alone for DME involving the central macula; and the Protocol K finding that visual improvement continues long term after focal/grid photocoagulation without additional treatment. Protocol F suggested that panretinal photocoagulation in one sitting vs. four was equally effective, Protocol J supported combined therapy with laser and intravitreal steroid or anti-VEGF, Protocol C showed that retinal thickness measured by OCT was fairly stable from 8 a.m. to 4 p.m., and Protocol G showed that subclinical DME progresses to clinically significant DME in 25% to 50% of patients. Protocol O established macular thickness of 320 µm for men and 305 µm for women as normal and showed that different OCT devices generate different macular thickness measurements, but that they can be normalized to one another. All in all, more than 25 well-managed prospective clinical trials have resulted in more than 65 peer-reviewed publications with many more to come.
The recent groundbreaking DRCR.net clinical trial looking at the comparative efficacy of the three available anti-VEGF injectables is discussed in the accompanying cover story. Interested ophthalmologists can learn more on the public website for DRCR.net.
In my opinion, these clinical trials have been a very productive use for some of the approximately $675 million a year currently appropriated by Congress to the NEI. I would love to see similar clinical trials help us better understand many areas of therapeutic controversy and ambiguity in the treatment of anterior segment disease. The American Society of Cataract and Refractive Surgery has recently funded the establishment of a Clinical Research Council (CRC) whose goal is to mirror the exemplary collaboration among our vitreoretinal colleagues. My colleagues at Minnesota Eye Consultants and I look forward to participating in future clinical trials catalyzed by the ASCRS CRC.