Agomelatine in Generalized Anxiety Disorder: An Active Comparator and Placebo-Controlled Study

Background: Agomelatine was efficacious in reducing symptoms in a short-term placebo-controlled trial in generalized anxiety disorder (GAD) and in preventing relapse in a longer term placebo-controlled study. An additional short-term placebo-controlled study is required by regulatory agencies to confirm the efficacy of agomelatine in GAD. Method: This 12-week, placebo-controlled, double-blind, randomized, parallel group, international, multicenter study was designed to confirm the efficacy of agomelatine 25-50 mg/d in the treatment of patients with a primary DSM-IV-TR diagnosis of GAD. The primary outcome measure was the Hamilton Anxiety Rating Scale (HARS) total score. Assay sensitivity was evaluated by including an escitalopram (10-20 mg/d) group. Settings: The study was undertaken in 45 clinical centers in Argentina, Czech Republic, Finland, South Korea, Poland, Russia, and Slovakia from April 2010 to July 2011. Results: One hundred thirty-nine outpatients were included in the agomelatine group, 131 in the placebo group, and 142 in the escitalopram group. Agomelatine significantly reduced mean (SD) HARS total score (agomelatine-placebo difference: 4.71 [1.03], P < .0001) and had significant effects on secondary outcome measures, including psychic and somatic HARS subscales, response rate (estimate [standard error]) (agomelatine-placebo difference: 27.4% [5.9%], P < .0001), remission on the HARS (agomelatine-placebo difference: 16.8% [5.4%], P = .002), Clinical Global Impressions-Severity of Illness scale (CGI-S) (P < .001), functional impairment (P < .0001), and sleep quality (P < .001). Findings were confirmed in the subset of more severely ill patients (HARS total score >= 25 with or without CGI-S >= 5 at baseline). Agomelatine was well tolerated by patients, with no more adverse events than placebo. Escitalopram was similarly efficacious but was accompanied by a higher incidence of adverse events compared to placebo. Conclusions: In clinical practice, agomelatine has at least similar efficacy to that of escitalopram for the short-term treatment of GAD and is well tolerated.