Efficacy and tolerability of 0.2% brimonidine tartrate for the treatment of acute non-arteritic anterior ischemic optic neuropathy (NAION): a 3-month, double-masked, randomised, placebo-controlled trial

Abstract

Introduction: Neuroprotection may be an option in ischemic optic nerve disease. There have been promising reports about the neuroprotective ability of topical brimonidine in animal studies. Therefore, we tested whether 0.2% brimonidine tartrate could improve the outcome of patients with non-arteritic anterior ischemic optic neuropathy (NAION). The study was stopped after an interim analysis, having not proven its feasibility within practicable time frame.

Methods: A 3-month, double-masked, placebo-controlled, randomised European multicenter trial conducted according to good clinical practice rules. Thirty-six patients (22 m, 14 f), older than 40 years with first eye involvement and typical signs of NAION were included in the study within the 1st week after visual loss (VA 0.05-1.0) and were randomized to treatment with either brimonidine 0.2% (Alphagan) or placebo. Visual acuity (VA, primary endpoint), visual field (VF, Humphrey 30-2 and Goldmann, quantified by a modified Esterman grid) and automated swinging flashlight test (SWIFT) were performed at baseline, 2 weeks, 4 weeks and 12 weeks after first visit. Primary analysis aimed at intention-to-treat group (ITT, n=29), secondary analysis to the per protocol population (PP, n=25). Tolerability and safety were tested in the safety group (n=36). A two-sample two-sided t-test was used for statistical analysis (alpha level at 0.05).

Results: VA did not show statistically significant difference by treatment. There were non-significant trends for better visual field results in the brimonidine group. Adverse events consisting of local irritation were observed six times in the verum and three times in the placebo group. No serious adverse events occurred.

Conclusion: In contradiction to an open-labeled, retrospective study published by Fazzone et al., the results of this trial did not indicate any harmful effect of brimonidine in patients suffering from NAION. However, a statistically significant advantage for the patients receiving brimonidine tartrate could not be shown.