TOPICAL ADMINISTRATION OF SOMATOSTATIN AND BRIMONIDINE IN THE EARLY STAGES OF DIABETIC RETINOPATHY: RESULTS OF THE EUROCONDOR STUDY

Abstract

Purpose : To present the initial results of the first clinical trial using neuroprotective agents (somatostatin 0.1% [SST] and brimonidine tartrate BMN 0.2% [BMN]) administered in eye drops for treating DR (EUROCONDOR- European Consortium for Early treatment of Diabetic Retinopathy- clinical trial (NCT01726075). The primary objective was to assess whether these neuroprotective drugs, administered topically, were able to prevent or arrest neurodegeneration, as well as the development and progression of the early stages of DR.

Methods : 449 type 2 diabetic patients with either no visible DR (ETDRS level <20; n=193) or only early stages of DR (ETDRS level 20-35; n=256) were enrolled in a prospective (2 years of follow-up), multicenter and randomized clinical trial. Exclusion criteria included retinal diseases associated with neurodegeneration, renal failure, and HbA1c > 10% in the previous 6 months before recruitment. Eye drops were administered twice per day in each eye. Color fundus photography, SD-OCT and mfERG were performed every 6 months and graded by a centralized reading center.

Results : Similar clinical features and degree of metabolic control (HbA1c) were observed among the three arms (placebo, SST and BMN) at baseline and during follow-up. We did not observe differences at the end of follow-up regarding new cases of neurodegeneration among the three arms. However, in those patients in whom neurodegeneration was already detected at baseline (≥6 abnormal hexagons for implicit time in mfERG), SST and BMN arrested the progression of neurodegeneration in comparison with placebo (p<0.01). No effect was observed in the development or progression of microvascular disease assessed by ETDRS scale. The overall drop-out rate was 23%. The only remarkable secondary effect was the high local side effects reported with BMN, which significantly contributed to the drop-outs.

Conclusions : Topical administration of SST and BMN are useful in arresting the progression of neurodegeneration in early DR. The high rate of local adverse effects observed with BMN seems a limiting factor for using this drug as chronic treatment. Further studies with SST with more longer follow-up in order to determine whether this beneficial neuroprotective effect results in reduction of microvascular disease are needed.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.