Baruch D. Kuppermann, MD, PhD (Irvine, CA),* Connie Chou, PhD (Irvine, CA),* David V. Weinberg, MD (Milwaukee, WI),* Scott M. Whitcup, MD (Irvine, CA),* Julia A. Haller, MD (Baltimore, MD),* Mark S. Blumenkranz, MD (Stanford, CA),* George A. Williams, MD (Royal Oak, MI)*

PURPOSE:

To evaluate the response of different patterns of persistent diabetic macular edema (DME) unresponsive to prior medical or laser therapy to treatment with a novel intravitreal sustained-release dexamethasone posterior-segment drug-delivery system (dexamethasone DDS).

METHODS:

Prospective, multicenter, masked, randomized, controlled clinical study. Eyes with central macular edema due to diabetic retinopathy unresponsive to prior medical or laser therapy for at least 3 months with a best-corrected ETDRS visual acuity (BCVA) of 20/40 to 20/200 were randomized to observation or treatment with 350 μg or 700 μg dexamethasone DDS (n=57
per group). At baseline, DME was characterized as focal (n=96); cystoid (n=66); diffuse (n=94); or combined cystoid and diffuse (cystoid-diffuse; n=51) based on the clinical exam. (Note: patients could exhibit more than one pattern of DME). Outcome measures included BCVA and central retinal thickness measured by OCT.

RESULTS:

Efficacy was seen across all patterns of DME, but there was a significant treatment-by-DME pattern interaction (P=.038) favoring the 700 μg dose when cystoid-diffuse DME was present. At day 90, an improvement of =10 letters was seen in 42% (11/26) of cystoid-diffuse eyes in the 700μg group (P=.001 vs observation), 17.2% (5/29) in the 350 μg group (P=.123 vs observation), and 4% (1/25) of eyes in the observation group. Other patterns of ME showed =10 letter improvement in 32-39% of eyes. (P=.04 to .004 vs observation) in the 700 μg group and in 18-24% of eyes in the 350 μg group (P=.283 to .165 vs observation). Changes in central retinal thickness for all DME patterns ranged from -132 to -183 μm in the 700 μg group (P=.005 to <.001 vs observation), and from +4.6 to -45 μm in the 350 μg group (P=.589 to .061 vs observation) while the among-group treatment-by-DME pattern interaction was borderline statistically significant (700 μg group only) at P=.058.

CONCLUSION:

Despite failing prior therapy, eyes with all patterns of DME had significant improvements in BCVA and central retinal thickness following treatment with 700 μg dexamethasone in a novel intravitreal sustainedrelease posterior-segment drug-delivery system. Eyes with combined cystoid-diffuse DME showed a more favorable response than other patterns of
DME.
* Financial interest disclosed