April 28, 2010
Comparative-effectiveness study confirms new treatment for diabetic macular edema
Researchers have shown that ranibizumab (Lucentis) eye injections, often in combination with laser treatment, result in better vision than laser treatment alone for diabetes-associated swelling of the retina.
Laser treatment alone has been the standard care for the past 25 years. But nearly 50 percent of patients who received this new treatment experienced substantial visual improvement after one year, compared with 28 percent who received the standard laser treatment. The study involved 52 clinical sites within the Diabetic Retinopathy Clinical Research Network (DRCR.net), supported by the National Eye Institute (NEI) and the National Institute of Diabetes and Digestive and Kidney Diseases, part of the National Institutes of Health.
The UW was one of the clinical sites participating in the study. Dr. James Kinyoun, a professor of ophthalmology who practices at the UW Medicine Eye Institute, led the UW clinical site for this research.
The chair of the Diabetic Retinopathy Clinical Research Network Dr. Neil Bressler said, “These results indicate a treatment breakthrough for saving the vision of people with diabetic macular edema. Eye injections of ranibizumab with prompt or deferred laser treatment should now be considered for patients with characteristics similar to those in this clinical trial.” Bressler is chief of the Retina Division at the Wilmer Eye Institute, Johns Hopkins University, Baltimore, Md.
Diabetic retinopathy is the most common cause of vision loss in working-age Americans. This condition damages the small blood vessels in the eye’s light-sensitive retinal tissue. When these damaged blood vessels begin to leak fluid near the center of the retina, known as the macula, macular edema occurs. The macula provides detailed central vision used for such activities as reading, driving, and distinguishing faces. In macular edema the retinal tissue swells, which can lead to vision loss if left untreated.
Laser treatment of the retina has been the standard care for diabetic macular edema since an NEI-supported study in 1985 showed it to be beneficial. However, recent small short-term studies have revealed the visual benefits of eye injections of medications that block a chemical signal that stimulates blood vessel growth, known as vascular endothelial growth factor (VEGF). These studies have indicated that repeated doses of anti-VEGF medications, such as ranibizumab, may prevent blood vessels from leaking fluid and causing macular edema. The DRCR.net study, published online April 27 in Ophthalmology, confirms preliminary results and provides evidence of the treatment’s effectiveness in combination with laser therapy through at least one year of follow up.
“This comparative-effectiveness study demonstrated that a new treatment can protect and, in many cases, improve the vision of people with diabetic macular edema,” said NEI Director Dr. Paul A. Sieving.
“For over 20 years, laser coagulation has been the main treatment for diabetic macular edema,” said the UW clinical site director Dr. James Kinyoun, “Although effective in decreasing vision loss, laser treatment has not been very effective in improving vision already lost from diabetic macular edema. Now, ophthalmologists have a treatment that not only is more effective in decreasing vision loss, but also in improving vision already lost to diabetic macular edema. The treatment does not result in the macular scars due to laser coagulation, and overall, the risk of intravitreal ranibizumab is very low.” Intravitreal refers to the delivery of medication into the eye.
The study results appear in the Ophthalmology article titled, “Randomized Trial Evaluating Ranibizumab Plus Prompt or Deferred Laser or Triamcinolone Plus Prompt Laser for Diabetic Macular Edema.” Ophthalmology is the official journal of the American Academy of Ophthalmology.
The current study included a total of 854 eyes of 691 people, who had one or both eyes treated. Participants, who were on average in their early 60s, were diagnosed with type 1 or 2 diabetes and macular edema. They were randomly assigned to one of four study groups: sham injections plus prompt laser treatment within one week; ranibizumab injections plus prompt laser treatment; ranibizumab plus deferred laser treatment after six months or more; or injections of corticosteroid medication known as triamcinolone (Trivaris) plus prompt laser treatment.
Ranibizumab injections could be given as often as every four weeks, and triamcinolone injections or laser treatments could be given as often as every 16 weeks. In general, treatment was continued until a participant’s vision or retinal thickness returned to normal, or additional treatment did not improve vision or retinal swelling.
After one year, nearly 50 percent of eyes treated with ranibizumab and prompt or deferred laser treatment showed a substantial visual improvement. People could read at least two additional lines on an eye chart with the treated eye, or letters that were at least one-third smaller than they could read before the study treatment. Fewer than 5 percent of eyes in these groups experienced a visual loss of two or more lines. The results were similar whether patients received prompt or deferred laser treatment with the ranibizumab injections.
In contrast, about 30 percent of eyes that received laser treatment alone or triamcinolone plus laser showed a visual improvement of two or more lines on an eye chart, while 13 to 14 percent of eyes in these groups had a visual loss of two or more lines.
Although participants in all three injection groups had a greater decrease in retinal thickness after one year than with laser treatment alone, patients who received the triamcinolone corticosteroid injections had greater complication rates. About 30 percent of people in the triamcinolone group developed high eye pressure that required medications, and about 60 percent developed cataracts that required surgery.
Few participants who received eye injections of ranibizumab had eye-related complications, such as an infection inside the eye likely caused by the injections, or worsening of a retinal detachment that existed prior to beginning treatment. The study found that eye injections of ranibizumab were not associated with any serious risks such as heart attack or stroke. DRCR.net researchers will continue to monitor the study participants for at least three years to obtain additional information about the safety and effectiveness of these macular edema treatments.
“The UW Medicine Department of Ophthalmology has been an active participant in national collaborative studies to find the best treatment for diabetic retinopathy, including diabetic macular edema, for more than 30 years,” Kinyoun said. “The study results released today are from another one of the several studies sponsored by the National Eye Institute in which we have participated. Our faculty and study personnel are committed to studies that provide the evidence necessary for ophthalmologists and their patients to decide what is the best treatment for diabetic eye disease, and this study today provides answers for diabetic macular edema.”
Other UW Medicine researchers for the study, in addition to Kinyoun, are Gurunadh Atmaran Vemulakonda, Susan Rath, Pendra Kay Burrows, Patricia K. Ernst, Juli A Pettingill, Brad C. Clifton, James D. Leslie and Chuck Stevens, all from the Department of Ophthalmology.
Find more information about this clinical trial (trial number NCT00444600).
The National Institute of Diabetes and Digestivi and Kidney Diseases, part of NIH, conducts and supports basic and clinical research and research training on some of the most common, severe, and disabling conditions affecting Americans. The Institutes research interests include diabetes and other endocrine and metabolic diseases; digestive diseases, nutrition, and obesity; and kidney, urologica and hematologic diseases. For more information, visit www.niddk.nih.gov
The National Eye Institute, part of the National Institutes of Health (NIH), leads the federal government’s research on the visual system and eye diseases. NEI supports basic and clinical science programs that result in the development of sight-saving treatments. For more information, visit www.nei.nih.gov
The National Institutes of Health (NIH) — The Nation’s Medical Research Agency — includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical, and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.