Efficacy of the Novel Antidepressant Agomelatine on the Circadian Rest-Activity Cycle and Depressive and Anxiety Symptoms in Patients With Major Depressive Disorder

OBJECTIVE: This study evaluates the efficacy of agomelatine, the first antidepressant to be an agonist at MT(1)/MT(2) receptors and an antagonist at 5-HT(2C) receptors, versus sertraline with regard to the amplitude of the circadian rest-activity cycle and depressive and anxiety symptoms in patients with major depressive disorder (MDD). METHOD: Outpatients with DSM-IV-TR-defined MDD received either agomelatine 25 to 50 mg (n = 154) or sertraline 50 to 100 mg (n = 159) during a 6-week, randomized, double-blind treatment period. The study was conducted from 2005 to 2006. The main outcome measure was the relative amplitude of the individual rest-activity cycles, expressed as change from baseline to week 6 and collected from continuous records using wrist actigraphy and sleep logs. Secondary outcome measures were sleep efficiency and sleep latency, both derived from actigraphy, and efficacy on depression symptoms (17-Item Hamilton Depression Rating Scale total score and Clinical Global Impressions scale scores) and anxiety symptoms (Hamilton Anxiety Rating Scale total score and subscores). RESULTS: A significant difference in favor of agomelatine compared to sertraline on the relative amplitude of the circadian rest-activity cycle was observed at the end of the first week (P = .01). In parallel, a significant improvement of sleep latency (P <.001) and sleep efficiency (P <.001) from week 1 to week 6 was observed with agomelatine as compared to sertraline. Over the 6-week treatment period, depressive symptoms improved significantly more with agomelatine than with sertraline (P <.05), as did anxiety symptoms (P <.05). CONCLUSIONS: The favorable effect of agomelatine on the relative amplitude of the circadian rest-activity/sleep-wake cycle in depressed patients at week 1 reflects early improvement in sleep and daytime functioning. Higher efficacy results were observed with agomelatine as compared to sertraline on both depressive and anxiety symptoms over the 6-week treatment period, together with a good tolerability profile. These findings indicate that agomelatine offers promising benefits for MDD patients. TRIAL REGISTRATION: www.isrctn.org: ISRCTN49376288.