A drug may be more effective against the leading cause of adult blindness than laser treatments, a new study has shown.
Researchers at the University of Illinois at Chicago College of Medicine participated in a national multi-center trial comparing treatments for diabetic macular edema, a swelling of the retina associated with diabetes, that is the major cause of blindness among adult Americans.
The study looked at treatment by injection of the drug ranibizamb -- marketed by Genentech as Lucentis -- by comparing it to laser treatment, which has been the standard of care for the last 25 years.
The study, which will be published online in the journal Ophthalmology, followed 691 people who had one or both eyes treated at 52 sites, including UIC.
The study "shows the power of targeted treatment for diabetic macular edema," said Dr. Jennifer Lim, professor and Charles I. Young Chair of Ocular Research in Ophthalmology and Visual Science at UIC and a site principal investigator on the study. "We were able to achieve much higher visual acuity improvements than ever before," she said, and without significant side effects.
Patients were randomly assigned to four treatment groups: sham injections plus prompt laser treatment (within one week), ranizumab injections plus prompt laser treatment, ranizumab plus deferred laser treatment after six months or more, or injections of a corticosteroid drug plus prompt laser treatment.
After one year, nearly half the eyes treated with ranizumab showed substantial eye improvement. Patients were able to read at least two additional lines on an eye chart than before treatment. Results were similar whether ranizumab treatment was accompanied by prompt or delayed laser treatment. Fewer than 5 percent of patients in the ranizumab treatment groups experienced a visual loss of two or more lines.
Only about 30 percent of patients receiving laser treatment alone or corticosteroid plus laser improved their ability to read 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.
The findings echoed an earlier, smaller study that compared ranibizumab alone versus ranibizumab plus laser treatment or laser alone, said Lim, who served on the executive committee of the earlier study. In that study, after six months the ranibizumab-alone eyes also did best, "and we have unpublished data that suggests the results held after one year as well," she said.
"Ranizumab is an important new treatment option for people with diabetes," said Lim, who is director of retina services at UIC. She said she hoped that the high complication rate for patients treated with the corticosteroid would help to end the use of this outmoded treatment option.
Dr. Michael Blair, assistant professor of ophthalmology and visual sciences, also acted as a site principal investigator on the study.
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