Clinical applications of the sustained-release dexamethasone implant for treatment of macular edema

Abstract

Macular edema is one of the leading causes of vision loss among patients with retinal vein occlusion, diabetic retinopathy, and posterior chamber inflammatory disease. However, the treatment of macular edema is considerably limited by the difficulty in delivering effective doses of therapeutic agents into the vitreous cavity. In recent years, the development of a sustained-release dexamethasone intravitreal implant (Ozurdex(®)) has enabled more controlled drug release at a stable rate over a long period of time, with a potentially lower rate of adverse events. Clinical studies indicate that this dexamethasone implant is a promising new treatment option for patients with persistent macular edema resulting from retinal vein occlusion, diabetic retinopathy, and uveitis or Irvine-Gass syndrome.

Keywords: Ozurdex®; diabetic retinopathy; macular edema; posterior-segment inflammatory disease; retinal vein occlusion; sustained-release dexamethasone implant.

Figure 1

Dexamethasone Posterior Segment Drug Delivery System^® Applicator and approximate vitreous location of dexamethasone implant after insertion. The implant is approximately 6 mm long and is inserted into the vitreous cavity through the 22-gauge needle of the applicator.

Figure 2

Temporal kinetics of dexamethasone concentrations in the vitreous cavity, retina, and plasma following placement of the 0.7 mg dexamethasone implant in monkeys. The dexamethasone concentration was below the minimum detection limit in plasma after day 60.

Figure 3

Percentage of patients with a ≥10-letter or a ≥15-letter improvement in best corrected visual acuity following treatment with the 0.7 mg dexamethasone implant at days 90 and 180. Notes: ^aP < 0.001, ^bP = 0.06, ^cP = 0.006, and ^dP = 0.02 compared with observation. A P < 0.025 was considered a statistically significant difference. Abbreviation: DEX, dexamethasone.

Figure 4

Efficacy of the dexamethasone implant in improving BCVA stratified by the underlying cause of macular edema in patients who participated in the Phase II trial. Notes: ^aP not determined; ^bP = 0.029 and ^cP = 0.007 compared with the observation group; ^duveitis or Irvine-Gass syndrome; ^en = 35 for the 0.7 mg dexamethasone implant; ^fn = 13 for the 0.7 mg dexamethasone implant. Abbreviations: DEX, dexamethasone; BVCA, best corrected visual acuity.

Figure 5

Time to achieve 15 letters of improvement from baseline BVCA in patients with macular edema secondary to central retinal vein occlusion or branch retinal vein occlusion who participated in the Phase III trials. Abbreviations: DEX, dexamethasone; BVCA, best corrected visual acuity.

Figure 6

Mean change from baseline BVCA in patients with macular edema secondary to central retinal vein occlusion or branch retinal vein occlusion who participated in the Phase III trials. Notes: ^aP ≤ 0.006 compared to sham. Abbreviations: DEX, dexamethasone; BVCA, best corrected visual acuity.

Figure 7

Mean change from baseline BCVA stratified by the underlying cause of macular edema of patients who participated in the Phase III trials. Notes: ^aP < 0.001, ^bP = 0.008, and ^cP = 0.305 compared to sham. Abbreviations: DEX, dexamethasone; BVCA, best corrected visual acuity; BRVO, branch retinal vein occlusion; CRVO, central retinal vein occlusion.