PHOENIX – Vilazodone was associated with significantly higher rates of response and remission than placebo, and it demonstrated efficacy across all symptoms in patients with major depressive disorder in an analysis of pooled data from two pivotal randomized controlled trials.
The efficacy of the serotonin reuptake inhibitor and 5-HT receptor partial agonist was established in the two 8-week phase III studies, and safety and tolerability were demonstrated in a 52-week open-label phase III study. These findings led to the 2011 Food and Drug Administration approval of vilazodone hydrochloride under the trade name of Viibryd for treatment of MDD in adults.
The current post hoc pooled analysis of data from the two 8-week studies further demonstrates the drug’s efficacy across the symptoms of depression, Dr. Arif Khan and colleagues reported in a poster at a meeting of the New Clinical Drug Evaluation Unit sponsored by the National Institute of Mental Health.
Compared with 432 patients who received placebo, the 431 patients randomized to receive vilazodone experienced significant improvements in Montgomery-Åsberg Depression Rating Scale (MADRS) scores (least squared mean difference of –2.79), as well as significant improvement on all secondary measures, including the Hamilton Depression Rating Scale (HAMD), the Clinical Global Impressions-Improvement (CGI-I) and Severity (CGI-S) scales, and the Hamilton Anxiety Rating Scale (HAMA), according to Dr. Khan of the Northwest Clinical Research Center in Bellevue, Wash.
Response defined by at least 50% improvement on the MADRS occurred in 42% of vilazodone and 29% of placebo patients. Response defined by a 50% or greater improvement on the HAMD occurred in 44% and 33% of the patients, respectively, and response defined by achievement of a CGI-I score of 2 or less occurred in 49% and 35% of the patients, respectively. Remission defined as a MADRS score of 10 or less occurred in 29% of the vilazodone and 20% of the placebo patients, and remission defined as a MADRS score of 12 or less occurred in 35% vs. 22% of the patients, respectively.
Significant improvement in favor of vilazodone also was seen on change from baseline in every MADRS single item, including apparent sadness, reported sadness, inner tension, reduced sleep, reduced appetite, concentration difficulties, lassitude, inability to feel, pessimistic thoughts, and suicidal thoughts.
The patients were adults aged 18-65 years in the first trial and 18-70 years in the second. All met diagnostic criteria for MDD according to the DSM-IV-TR, and they all underwent a washout period of at least 2 weeks, a 1-week screening period, and an 8-week double-blind treatment period. Vilazodone was titrated from a 10-mg dose once daily for 7 days to 20 mg once daily for the next 7 days and 40 mg once daily thereafter.
The findings demonstrate that vilazodone is significantly superior to placebo on all depression rating scales tested, Dr. Khan noted.
"Additionally, superiority versus placebo on all MADRS single items demonstrated the broad efficacy of vilazodone across the spectrum of depression symptoms," he wrote, also noting that "the selection of a therapeutic agent that effectively resolves a broad spectrum of symptoms and promotes a return to full functioning is an important component of depression treatment."
Dr. Khan reported having no conflicts of interest to disclose. This study was supported by Forest Laboratories. Other authors are employees of Forest Research Institute, a scientific subsidiary of Forest Laboratories.