Patients switched to dexamethasone delivered via an implanted device did not experience significant differences compared with those maintained on anti-vascular endothelial growth factor (VEGF) injections in the management of treatment-resistant diabetic macular edema (DME), according to research published in BMC Ophthalmology. Researchers compared patients switched to dexamethasone with patients treated using continued intravitreal injections after their macular edema persisted in spite of anti-VEGF therapy. The researchers say neither group had notable differences in best-corrected visual acuity (BCVA), central macular thickness (CMT), or intraocular pressure (IOP).
The researchers conducted the retrospective study to compare the efficacy of monthly anti-VEGF injection vs dexamethasone implant in patients with DME whose macular edema persisted following 3 doses of anti-VEGF therapy. The study took place between January 2014 and January 2019.
The study included patients with CMT thicker than 300 μm who had previously received 3 doses of anti-VEGF therapy (aflibercept or ranibizumab). The researchers divided the patients into 4 groups: those who received 3 more doses of the initial anti-VEGF treatment (aflibercept followed by aflibercept [AFL-AFL] or ranibizumab followed by ranibizumab [RAN-RAN]) and patients switched to dexamethasone implant treatments (aflibercept followed by dexamethasone [AFL-DEX] or ranibizumab followed by dexamethasone [RAN-DEX]). The primary outcome measures were BCVA, CMT, and IOP at 6 months.
A total of 94 eyes of 94 patients (mean age, 64.64±7 years; 61.7% men and 38.3% women), were included in the study. The groups showed no significant difference in age, stage of retinopathy, and lens status.
After 6 months of follow up, the researchers found no significant differences between patients switched to dexamethasone vs those maintained on injections in BCVA (AFL-AFL, 0.49±0.22; RAN-RAN, 0.57±0.38; AFL-DEX, 0.62±0.38; RAN-DEX, 0.80±0.43 logMAR; P =.159), CMT (AFL-AFL, 291.6±54.4; RAN-RAN, 293.1±79.5; AFL-DEX, 320±103.8; RAN-DEX, 332.5±96.8 μm; P =.295), or IOP ; IOP (AFL-AFL, 15.9±3.5; RAN-RAN, 15.59±4; AFL-DEX, 15.9±3; RAN-DEX, 18.1±3.8 mm Hg; P =.109).
At the conclusion of month 6, researchers say those in the groups that continued with 3 doses of anti-VEGF after 3 doses of anti-VEGF treatment and the patients switched dexamethasone implants did not experience any statistically significant decrease in central macular thickness, rise in intraocular pressure, or improvement in visual acuity.
“According to the results of our research, after three doses of anti-VEGF (3rd month), to apply for a medication change (to switch to dexamethasone implant treatment) should be selected according to the patient (presence of glaucoma, compliance with treatment, etc.) and cost. Dexamethasone implant has an advantage over anti-VEGF in that it needs fewer injections, and its cost is cheaper than three doses of anti-VEGF,” according to the researchers.
Limitations of the study included the retrospective design, small sample sizes in the groups, inability to evaluate inflammatory markers, and short follow-up duration.
Koc H, Alpay A, Ugurbas SH. Comparison of the efficacy of intravitreal anti-VEGF versus intravitreal dexamethasone implant in treatment resistant diabetic macular edema. BMC Ophthalmol. 2023;23(1):97. doi:10.1186/s12886-023-02831-6