Diabetic macular edema

Is there a way to predict success of anti-VEGFs in diabetic macular edema?

Clinicians may be able to predict a patient’s long-term response to anti-vascular endothelial growth factor (VEGF) treatment of diabetic macular edema (DME) after three injections. This study was presented at AAO 2015 by Dr Pravin Dugel. 

These conclusions are based on a post hoc analysis of the Protocol 1 3-year phase III trial of 854 eyes in 691 patients with DME conducted by the Diabetic Retinopathy Clinical Research Network. That study compared prompt versus delayed laser treatment in eyes treated with ranibizumab for diabetic macular edema.

In their analysis, Dr. Dugel and his colleagues assessed outcomes in three cohorts based on best-corrected visual acuity observed. 

After giving the patients three injections in 12 weeks, they divided them into three cohorts: those who gained less than five ETDRS letters of best-corrected visual acuity, those who gained five to nine letters, and those who gained 10 or more letters.

They found a close correlation between the letters gained at 12 weeks and the letters gained at three years. The differences among the cohorts were statistically significant (p < 0.001).

Change in Mean BCVA

Cohort

Mean Letters Gained at 12 weeks

Mean Letters Gained at 3 years

0-4 Letters

0.3 3.0

5-9 Letters

6.9 8.2

≥ 10 Letters

15.2 13.8

As per Dr Dugel, if the patients do not respond after three injections of an anti-VEGF medication, clinicians can then try dexamethasone intravitreal implants. This drug may last for 3-5 months. If the fluid repeatedly returns, a clinician could next offer a fluocinolone acetonide intravitreal implant, which is a non-biodegradable device and may last for three years.

If patients who aren’t responding to anti-VEGF therapy don’t switch to one of these alternatives quickly enough, they could lose visual acuity that might have been preserved.

It is not yet clear why some patients with DME respond well to anti-VEGF therapy and some do not. There may be a natural progression of the disease from a primarily permeability driven phase to a primarily inflammation driven phase. Environmental and genetic factors may both play a role and research may lead to other tests.

Dr Dugel added that at some point, there may be a genetic marker or a biomarker, but until then, the above parameters give us some ability to distinguish patients with a high degree of accuracy.

Source

Featured image: topcon.co.jp

Posted in Diabetic Retinopathy, Implants, Pharmaceuticals/Drugs and tagged , , .