Because diabetic macular edema (DME) can persist in some patients despite anti-vascular endothelial growth factor (anti-VEGF) therapy, investigators looked to improve the outcomes for these patients and theorized that adding the dexamethasone implant (Ozurdex, Allergan) to anti-VEGF therapy with ranibizumab (Lucentis, Genentech) might solve the problem of the residual DME.
Diabetic Retinopathy Clinical Research (DRCR) investigators decided to add a dexamethasone implant to treat residual DME because it is FDA approved for the treatment of DME. After at least 6 months of monthly anti-VEGF therapy, between 32% and 66% of eyes can have residual DME, according to DRCR protocol T.
The question posed by the DRCR group was: Does the addition of the dexamethasone implant in patients treated with ranibizumab provide additional benefit to patients?
In this phase II, randomized clinical trial of the DRCR Network, the hopes for improved visual outcomes were not realized. When investigators compared the combination therapy of ranibizumab and dexamethasone with ranibizumab monotherapy, no significant differences in visual acuity were found between the 2 regimens at 6 months.
However, there was an improvement in the central macular thickness on optical coherence tomography (OCT) in patients who were randomized to the combination therapy, according to Sophie Bakri, MD. Dr. Bakri is a professor of ophthalmology, Mayo Clinic, Rochester, MN.