STEROIDS FOR VEIN OCCLUSION

The wait-and-see approach to treating retinal vein occlusion (RVO) is obsolete, according to Baruch D Kuppermann MD, PhD, of University of California, Irvine, USA.

“Steroids are uniquely positioned to address the cascade of events leading to macular oedema in eyes with RVO. Steroids block a multitude of actions in eyes with RVO. These include the inhibition of cytokines, prostaglandins and leukotrienes, decreased vascular permeability and increased tight junction integrity, leading to decreased paracellular permeability,” said Dr Kuppermann.

Speaking at a session of the 15th EURETINA Congress in Nice, France, Dr Kuppermann reminded the audience that 30 per cent of RVO patient eyes with macular oedema have vascular endothelial growth factor (VEGF) levels within normal limits, so anti-VEGF might not be able to help these eyes. Indeed, the cytokine IL-6 appears to be a better discriminator of disease than VEGF, which makes steroid treatment particularly efficacious.

“The SCORE trials compared the efficacy and safety of 1mg and 4mg doses of preservative-free intravitreal triamcinolone (IVTA) with observation (CRVO) or grid photocoagulation (BRVO) for eyes with vision loss associated with macular oedema. They concluded that IVTA is superior to observation for CRVO, and equivalent to laser for BRVO, albeit with an increased risk of cataract and intraocular pressure elevation, particularly for 4mg dose.

VITREOUS DURABILITY

Dr Kuppermann was particularly interested in the advantages of Kenalog® (triamcinolone) as compared to other steroid formulations. “Kenalog® has longer vitreous durability in animal models,” he said.

But research has moved on to more advanced delivery methods for intravitreal steroids. Dexamethasone is a more potent corticosteroid than triamcinolone. However, dexamethasone has an intraocular half-life of only three hours, necessitating a sustained-release formulation. Ozurdex® was developed with this in mind.

Dr Kuppermann has had significant experience with Ozurdex®, because it is readily covered by health insurance in the USA. Steroids have not gained the same type of preference as anti-VEGF agents in the treatment of RVO. Why might this be?

Dr Kuppermann pointed out that more than 80 per cent of patients in the GENEVA study (Ozurdex® for RVO) were enrolled more than three months after the onset of macular oedema, leading to lower efficacy than if treatment had been initiated earlier.

“Each month delay in treatment with Ozurdex® results in 11 per cent less likelihood of achieving 15-letter best corrected visual acuity improvement, so the ‘wait-and-see’ philosophy is obsolete. Early treatment of macular oedema in RVO unequivocally results in better outcomes,” he concluded.

Studies are ongoing to predict patients’ likelihood of being non-responders to anti-VEGF treatment, allowing steroid treatment to be started instead.

Baruch D Kuppermann: Bdkupper@uci.edu