Early corticosteroid intravitreal implant treatment needed for macular edema in RVO cases

Paolo Lanzetta

Macular edema associated with branch retinal vein occlusion or central retinal vein occlusion can be reduced using a dexamethasone intravitreal implant, but early treatment is necessary, according to a study.

“If treated early, patients can regain three or more lines of vision, but any delay decreases this likelihood in a highly significant manner,” Paolo Lanzetta, MD, said at the Euretina meeting in Paris.

These findings represent a paradigm shift, he said. Official guidelines state that there is no proven early treatment that will alter the visual prognosis in retinal vein occlusion, and surveillance has been recommended. Laser photocoagulation is indicated as the only available option in specific cases of neovascularization, and it should not be used earlier than 3 to 6 months after the initial event in BRVO.

“New pharmacotherapies are going to revolutionize our approach to RVO. Treatment options are available, should be started as early as possible and can indeed modify the visual prognosis,” Dr. Lanzetta said.

Ozurdex (dexamethasone intravitreal implant 0.7 mg, Allergan) is a biodegradable implant for sustained delivery of dexamethasone. It is injected intravitreally using a 22-gauge delivery system, providing a stable level of corticosteroids for about 3 months. Ozurdex was approved by the U.S. Food and Drug Administration in June 2009 for the treatment of macular edema associated with RVO.

In August 2010, following the results of the GENEVA clinical trial, it received marketing approval in Europe.

The study

The GENEVA study provided a unique opportunity to compare the response of immediate vs. delayed dexamethasone treatment. The trial enrolled 1,200 patients with macular edema associated with BRVO or CRVO. Approximately 80% of these patients had a relatively long duration of macular edema of 3 months or longer at baseline. Patients were randomly assigned to one of three groups: Ozurdex 700 µg, Ozurdex 350 µg or sham treatment for a period of 6 months.

In the following 6 months, all group received the active treatment.

“Our analysis showed a significant difference between delayed vs. early treatment groups. A 6-month delay was found to decrease by 60% the chance of gaining three or more lines of vision,” Dr. Lanzetta said.

“This allowed us to reach the first conclusion: Early treatment leads to a significantly better response in both BRVO and CRVO,” he said.

Second analysis

A second analysis was made to assess the impact of each month of treatment delay on the final outcome.

“For BRVO, we found a steady 10% decrease of the chances to gain three of more lines for each month of delay. At 1 month it was 10%, at 3 months it was approximately 30% and at 6 months it was 60%. For CRVO, we also found a progressive decrease, though on a reduced scale and of borderline significance,” Dr. Lanzetta said.

“The conclusion in this case was that increased duration of macular edema at the time of Ozurdex treatment is associated with a proportionally lower likelihood of gaining vision,” he said.

These findings will produce significant changes in clinical practice. After the diagnosis of macular edema in BRVO or CRVO, dexamethasone treatment should be started immediately to ensure patients have the best possible visual outcomes.

“Now there is no rationale for waiting and delaying the treatment,” Dr. Lanzetta said.

This new early-intervention approach will also be evaluated for other potential treatments, such as anti-VEGFs. – by Michela Cimberle

• Paolo Lanzetta, MD, can be reached at the University of Udine, Department of Ophthalmology, Piazzale S. Maria della Misericordia, 33100 Udine, Italy; 39-0432-559-905; fax: 39-0432-559-904; e-mail: paolo.lanzetta@uniud.it.
• Disclosure: Dr. Lanzetta is a consultant to Allergan.