Dexamethasone Implant Outperformed Laser in Phase 3 DME Trial

A dexamethasone 0.7 mg intravitreal implant administered every 5 months can provide superior outcomes for acuity and retinal thickness than 3-months-as-needed laser photocoagulation therapy, according to a12-month, randomized controlled trial published in Clinical Ophthalmology. The study, conducted from January 8, 2016 to November 1, 2019, analyzed the cases of 284 patients with fovea-involved diabetic macular edema (DME).

In fact, average change in best corrected visual acuity (BCVA) from baseline to 12 months for 145 individuals using the implant was 4.3 in Early Treatment Diabetic Retinopathy Study (ETDRS) letters, compared with 1.4 letters for 127 who completed the laser protocol (P =.001). Structural effects were also enhanced with DEX. Mean central retinal thickness (CRT) was reduced by -209.5 μm, compared with -120.3 μm for those in the laser group (P <.001). Total macular leakage area shown by fluorescein angiography changed by -8.367 mm² with the dexamethasone implant, compared with -0.637 mm² using laser treatment (P <.001).

The safety profile for the dexamethasone implant was acceptable — 33.1% in the implant cohort had a mean increase of IOP of 10 mm Hg or more above baseline, and 1 patient needed a trabeculectomy. Increases were managed with customary IOP-lowering eye drops, with therapy continuing as planned. IOP crested at 2 months after injection, dropping to almost baseline before the next dose. Also, cataract onset was experienced by 21.1% in the dexamethasone set and 7.8% of the laser group. Conversely, 17.1% of participants receiving laser displayed intensified macular scar, with only 1.4% of those who received the dexamethasone implant exhibiting a worsened macular scar.

The analysis notes that improvement of BCVA in the dexamethasone cohort after the first 2 injections did not similarly occur after the third; likely due to cataract. So, researchers conducted a subgroup analysis comparing phakic and pseudophakic eyes and found mean BCVA change at 12 months in dexamethasone-treated pseudophakic eyes was +4.7 letters, although change in phakic eyes was +2.0 letters. 

Examiners who assessed BCVA were masked to treatment regimen, but patients were not, and several participants in the laser cohort discontinued the study, possibly due to avoiding this therapy option, the study speculates. Another limitation was a global recall of medical supplies in December 2018, which reduced the study’s enrollment. However, this is the first randomized controlled trial directly comparing the dexamethasone implant with laser photocoagulation in DME care.

Dexamethasone implants may well benefit individuals who attain insufficient results with anti-VEGF treatment and “can also be considered for initial therapy in selected patients (eg, patients who are pseudophakic, pregnant, or not good candidates for anti-VEGF therapy,” according to the study.

Disclosures: This study was sponsored by Allergan, acquired by AbbVie Inc., and participated in the study’s design, analysis, and data interpretation. Also, several authors are affiliated with Allergan and AbbVie Inc. Please see the original reference for a full list of disclosures.

Reference

Wei W, Chen Y, Hu B, et al. Multicenter, prospective, randomized study of dexamethasone intravitreal implant in patients with center-involved diabetic macular edema in the Asia-Pacific region. Clinical Ophthalmol. Available online October 13, 2021. doi:10.2147/OPTH.S325618