The efficacy profile of vilazodone, a novel antidepressant for the treatment of major depressive disorder

Objective: Vilazodone is a novel serotonin reuptake inhibitor and serotonin 1A receptor partial agonist approved for the treatment of major depressive disorder (MDD). This evaluation presents side-by-side efficacy data from two randomized, double-blind, placebo-controlled, short-term 8-week trials (referred to as randomized controlled trial [RCT]-1 [N = 410] and RCT-2 [N = 481]); efficacy data for demographic and clinical subgroups (derived from pooled RCT data); and effectiveness data from a 52-week, open-label, long-term study (N = 616). The objective is to summarize the efficacy profile of vilazodone at its approved dose of 40 mg/day.

Methods: The main assessment in individual pivotal trials and pooled subgroup analyses was the change from baseline to end of treatment (EOT, 8 weeks) in the Montgomery-Åsberg Depression Rating Scale (MADRS) total score. Mixed-effects repeated-measures analyses were conducted in the placebo-controlled trials. Effectiveness analyses in the long-term study included mean MADRS score change over time.

Results: Vilazodone-treated patients in both short-term studies showed greater improvement from baseline to EOT in mean MADRS scores than placebo-treated patients (least-squares mean [LSM] treatment difference: -3.2 [p = 0.001], RCT-1; -2.5 [p = 0.009], RCT-2). Clinical Global Impressions-Improvement mean scores at EOT reflected greater improvement with vilazodone compared with placebo in both studies (LSM treatment difference: -0.4 [p = 0.001], RCT-1; -0.3 [p = 0.004], RCT-2). MADRS response rates were significantly greater among patients receiving vilazodone versus those receiving placebo (RCT-1: 40.4% versus 28.1%, respectively [p = 0.007]; RCT-2: 43.7% versus 30.3%, respectively [p = 0.002]). The greater efficacy of vilazodone versus placebo was consistent for the majority of demographic and MDD characteristic subgroups. In the long-term study, the mean MADRS score improved from 29.9 (baseline) to 11.4 (week 8), 8.2 (week 24), and 7.1 (week 52).

Conclusion: Vilazodone 40 mg/day resulted in clinically meaningful, statistically significant improvement in MDD symptoms in two placebo-controlled, 8-week studies. Findings are supported by subgroup analysis and open-label, long-term effectiveness data.

Trial registration: Randomized controlled trial 1: ClinicalTrials.gov identifier: NCT00285376, http://ClinicalTrials.gov/ct2/show/NCT00285376 ; randomized controlled trial 2: ClinicalTrials.gov identifier: NCT00683592, http://ClinicalTrials.gov/ct2/show/NCT00683592 ; open-label, long-term study: ClinicalTrials.gov identifier: NCT00644358, http://ClinicalTrials.gov/ct2/show/NCT00644358 .