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Evaluation of an Intravitreous Dexamethasone Drug Delivery System in Patients with Persistent Diabetic Macular Edema
Diabetic Retinopathy Highlights from Retina/Vitreous Free Papers
| Sunday, November 12, 2006 |
| George A Williams, MD, Julia A Haller MD, Baruch D Kuppermann, MD, PhD, Mark S Blumenkranz, MD, David V Weinberg, MD, Connie Chou, PhD, Scott M Whitcup, MD
Intravitreal corticosteroid therapy has been shown to reduce macular thickness, clear hemorrhage, and improve visual acuity in eyes with diabetic macular edema (DME). However, the need for frequent repeat injections, cataract formation, and increased intraocular pressure are significant limitations of intravitreal corticosteroids. The Posurdex device permits long-term intravitreal corticosteroid treatment, eliminating the need for frequent reinjections.
A safety and efficacy study of eyes with persistent DME of 7-90 days duration previously treated and unresponsive to medical or surgical treatment was conducted. Eyes were randomized to observation, 350 mcg, or 700 mcg dexamethasone (DEX) delivered via the Posurdex implant. At 90 days postimplantation, 33.3% of patients randomized to 700 mcg DEX had a 7-10 letter improvement in best-corrected visual acuity (BCVA). The number of patients included in the study was not stated, but this finding was statistically significant at P=.007 vs observation. 21.1% of patients randomized to 350 mcg DEX (P=.209) and 12.3% of patients randomized to observation experienced a similar improvement in BCVA. No cataract formation was observed. Efficacy persisted 180 days postimplantation. Intraocular pressure increased in 15%-18% of treated patients. Vitreous hemorrhage occurred in 21.8% of patients at both doses. Dr Williams concluded that patients with persistent DME respond favorably to 700 mcg DEX delivered by the Posurdex implant.
In the panel discussion, Dr Bressler noted the excellent study design. Dr Williams commented he would not consider Posurdex primary treatment for DME. Dr Haller noted that only 10% of patients experienced improvements in visual acuity ≥15 letters, and wondered whether this indicated that eyes with DME only have the potential to improve by about 10 letters. Dr Williams felt that neuroprotection would be the next development in DME treatment. |
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