Diabetic Macular Edema Has Low Response to Single Bevacizumab Dose

A single intravitreal bevacizumab dose is likely not an effective treatment for most patients with center-involving diabetic macular edema.

In the short-term, a single dose of intravitreal bevacizumab (IVB) for the treatment of diabetic macular edema (DME) may result in structural but not functional improvements, according to findings from an observational, retrospective study published in International Journal of Retina and Vitreous.

Researchers analyzed the electronic health records of 45 Patients (52 eyes; mean age, 64.22±8.12; 27 men, 19 women; 71.7% White) who underwent spectral domain optical coherence tomography at baseline, and 4-6 weeks after a single IVB treatment for DME between 2016 and 2021 the University of Kentucky in Lexington.

The patients had been diagnosed with type 2 diabetes a mean 18.47±9.92 years previously, and had an average glycated hemoglobin of 8.05±1.83%, best-corrected visual acuity (BCVA) of 63.9 ETDRS letters, and 31% had severe nonproliferative diabetic retinopathy.

More patients (n=27) were nonresponders than responders (n=19) to IVB treatment. At baseline, responders had significantly greater central subfield thickness (CST; mean, 560 vs 397 μm; P <.001), subretinal fluid (45.5% vs 13.3%; P =.01), fewer had vitreomacular adhesion (4.8% vs 28.7%; P =.03), and more had intraretinal cysts in the inner nuclear layer (95.5% vs 73.3%; P =.037) than nonresponders, respectively.

The anatomical response to IVB in our study cohort was sub-optimal with majority of patients being nonresponders.

Overall, at follow-up, patients had significantly decreased CST (mean, 466 vs 402 μm; P <.001) and total macular volume (TMV; mean, 10.45 vs 9.98 mm3; P <.001) with no improvement to BCVA (mean, 63.9 vs 65.9 ETDRS letters; P =.07).

Stratified by response, the responders did have BCVA improvement of 3.9 ETDRS letters compared with baseline (P =.026) following IVB treatment. Nonresponders were observed at follow-up to have an increase in CST by 9 µm (P =.47) and TMV by 0.08 mm3 (P =.25) compared with baseline.

This study was limited by its small sample size and retrospective design.

“The anatomical response to IVB in our study cohort was sub-optimal with majority of patients being nonresponders,” study authors report. “While no functional improvements were noted, structural responses were detected and some predictive factors of response were absence of vitreomacular adhesion, presence of posterior vitreous detachment, cystoid spaces in the inner nuclear layer, presence of subretinal fluid and higher baseline CST and TMV. These findings may provide further guidance for the initial management of center-involving DME in clinical practice when considering IVB as first-line treatment.”