Introduction: Vilazodone is a potent serotonin (5-HT) reuptake inhibitor and 5-HT₁A receptor partial agonist approved by the US Food and Drug Administration for the treatment of major depressive disorder (MDD) in adults. This study evaluated the efficacy and tolerability of vilazodone in the treatment of MDD.
Method: This 8-week, randomized (1:1), double-blind, placebo-controlled, parallel-group, fixed-dose study conducted from January 2012 to February 2013 compared vilazodone 40 mg/d with placebo in outpatients with DSM-IV-TR-diagnosed MDD. The primary efficacy measure was Montgomery-Asberg Depression Rating Scale (MADRS) total score change from baseline to week 8 analyzed by a mixed-effects model for repeated measures on the intent-to-treat population (placebo = 252, vilazodone = 253). Secondary efficacy outcomes were Clinical Global Impressions-Severity of Illness (CGI-S) Scale score change from baseline and MADRS sustained response rate (total score ≤ 12 for at least the last 2 consecutive double-blind visits).
Results: Approximately 83% of patients completed the study. Least squares mean differences (95% CI) were statistically significant for vilazodone versus placebo on MADRS (-5.117 [-6.886 to -3.347], P < .00001) and CGI-S (-0.622 [-0.845 to -0.399], P < .00001) change from baseline; statistically significant improvements versus placebo occurred at week 2 and persisted for the study duration. The MADRS sustained response rate was 17% for placebo and 27% for vilazodone (P < .01). Patients taking vilazodone versus placebo had higher rates of diarrhea and nausea; most incidences were mild in severity. Weight increase and sexual dysfunction adverse events were low in both groups.
Conclusions: A large and significant treatment effect on the MADRS and statistically significant improvement on the CGI-S demonstrated meaningful depressive symptom improvements. Vilazodone was generally well tolerated.
Trial registration: ClinicalTrials.gov identifier: NCT01473394.
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