DIABETIC RETINOPATHY

The results from a clinical trial currently under way in 11 different European clinical centres have the potential to profoundly alter the therapeutic management of diabetic retinopathy in the near future, according to a report at the 14th EURETINA Congress in London.

The therapeutic strategy of the European Consortium for the Early Treatment of Diabetic Retinopathy (EUROCONDOR) project is based on neuroprotection to prevent or arrest retinal neurodegeneration in the early stages of the disease, explained Rafael Simó MD, chairman of the project and Head of the Diabetes and Metabolism Research Unit, Val d’Hebrón Research Institute, Barcelona, Spain.

“It is a prospective and randomised study in 450 type 2 diabetic patients of two neuroprotective agents, somatostatin and brimonidine, administered topically through eye drops,” said Dr Simó.

There is growing evidence to suggest that retinal neurodegeneration plays an important role in the onset of diabetic retinopathy which participates in the development of microvascular abnormalities, said Dr Simó. The phase II and III EUROCONDOR clinical trial will assess whether therapeutic strategies based on neuroprotection are effective not only in preventing or arresting retinal neurodegeneration, but also in preventing the development and progression of the early stages of diabetic retinopathy, he said.

Focusing on the growing evidence of neurodegeneration as an early event in the pathogenesis of diabetic retinopathy, Dr Simó referred to a study published by his research group in 2007, which showed the high rate of apoptosis and reactive gliosis in diabetic eyes compared to non-diabetic controls.

More recently, Dr Simó's group has demonstrated that there is an imbalance between proapoptotic and survival signalling in the early stages of diabetic retinopathy.

“This imbalance in proapoptotic signalling promotes neuron death in diabetic patients. There is a lot of evidence demonstrating that neurodegeneration measured either by multifocal electroretinorgram or spectral domain OCT exists in the absence of microvascular impairment when we perform an ophthalmoscopic examination,” said Dr Simó.

Dr Simó said that the next step was to determine whether these abnormalities participate in microvascular disease.

Dr Simó said that the EUROCONDOR study design includes three groups of 150 patients: group A who receive placebo eye drops twice daily; group B who receive brimonidine tartrate eye drops (0.2 per cent) twice daily; and group C who receive somatostatin eye drops (one per cent) twice daily. Measurements taken include mfERG, frequency domain OCT, digital fundus photography and visual field assessments. The recruitment period for the EUROCONDOR trial ended in October 2013, with the final results expected in January 2016. One of the early results of the baseline data showed that, as expected, diabetic patients present an increase of implicit time abnormalities on multifocal electroretinogram (mfERG) readings.

Rafael Simó: rafael.simo@vhir.org