The Ozurdex Implant:  New hope for patients with macular edema, or not?

Macular edema is associated with the leading causes of blindness including diabetic retinopathy, macular degeneration and retinal vein occlusions.  After the completion of phase 2 and 3 clinical trials, the Ozurdex implant has now been approved for use in the treatment of macular edema associated with retinal vein occlusions.  Here we review the details about the device, its use in retinal diseases and the alternatives.

The Ozurdex Implant

First called Posurdex, the Ozurdex implant was renamed at the request of the FDA since a new implantation device was developed for delivery of the drug.  The device delivers a biodegradable intraocular implant containing dexamethasone which is injected into the vitreous and provides a stable level of corticosteroids into the back of the eye for up about 3 months.  Corticosteroids such as dexamethasone block chemical pathways that lead to inflammation, leakage from the retinal blood vessels, and macular edema. By reducing macular edema, the Ozurdex implant can reverse vision loss.  The device has been under study for the treatment of macular edema associated with vein occlusions, diabetic retinopathy and wet macular degeneration and was recently approved for treatment of retinal vein occlusions by the FDA and Medicare.

Results

An improvement of over 2 lines of vision was observed in 20-30% of patients in the two parallel clinical trials assessing efficacy for branch and central retinal vein occlusions.  There was a 25% incidence of significant elevation of IOP and a 4% incidence of cataract.  When compared with intravitreal triamcinolone used in a separate trial (the SCORE study) comparable results were reportedly acheived at a much lower cost.  In my own practice I have observed more sustained effects of Ozurdex over intravitreal triamcinolone injections and a more gradual and sustained reduction in macular edema and improvement in vision.

Alternatives:  Anti-VEGF drugs and Laser

Intravitreal injection of anti-VEGF drugs including the full size antibody, Avastin, the anti-body fragment, Lucentis, and the nucleic acid aptamer, Macugen, have all been found to be effective against vein occlusions and appear to be more effective than Ozurdex.  These agents, however, do not provide sustained release, are not always effective, and do not last long in previously vitrectomized eyes (weeks instead of months).  In addtion, they are absolutely contraindicated in pregnancy.  For those difficult cases that respond poorly to anti-VEGF drugs, Ozurdex can be an effective alternative or adjunctive treatment.  The example figure shows such a case in a CRVO patient no longer responsive to anti-VEGF drugs but improving with Ozurdex. 

Acute as well as chronic retinal vein occulusions now have treatment options that can restore vision and reduce complicaitons for our patients.  When retinal hemorrhages or edema are present, consider the diagnosis of retinal vein occlusion and prompt referral.  For those patients non responsive to conventional treatments, Ozurdex is now available as alternative or adjunctive therapy and may soon be used on other disorders as well.

Ron P. Gallemore, M.D, Ph.D.

Founder and Director

Retina Macula Institute and the

Retina Macula Research Center

South Bay 310-944-9393

Los Angeles 310-466-9393