MIAMI BEACH – Patients with generalized anxiety disorder (GAD) saw significant improvement in their work, family, and social lives when taking vilazodone, compared with placebo.
However, vilazodone was associated with more side effects, and men taking vilazodone experienced more sexual side effects than those on placebo, according to Dr. David Sheehan, distinguished university health professor emeritus at the University of South Florida, Tampa.
Dr. Sheehan and his collaborators from Forest Laboratories presented their findings during a poster session at a meeting of the American Society for Clinical Psychopharmacology, formerly known as the New Clinical Drug Evaluation Unit meeting.
Vilazodone is a selective serotonin reuptake inhibitor (SSRI) and a partial 5-HT1a receptor agonist. Already approved for the treatment of major depressive disorder (MDD), vilazodone showed anxiolytic properties in post hoc analyses of the MDD clinical trial data.
The randomized, double-blind, placebo-controlled trial enrolled 404 otherwise healthy men and women who met DSM-IV criteria for GAD, exhibiting physical and psychiatric symptoms as well as functional impairment from the persistent and pervasive worry that characterize GAD. Individuals with clinically significant depression or any suicide risk, previous lack of response to adequate trials of other SSRIs, and those with serious medical conditions were excluded from the study.
Enrollees underwent a 1-week screening period, followed by 8 weeks of treatment, ending with a 1-week, double-blinded period of tapering off the study drug or placebo. Patients with insufficient improvement were allowed to increase vilazodone dosing from 20 mg to 40 mg at the end of the second or fourth study week, with no increases permitted after week four of the study.
Overall, total scores on the Hamilton Rating Scale for Anxiety (HAM-A) improved significantly more for those taking vilazodone than for those on placebo (total HAM-A score difference -2.2, P = 0.005). The psychic, somatic, and anxiety subscales also showed significant improvement, compared with placebo, as did the anxious and tension items.
The results indicate “greater improvement in anxiety symptoms associated with GAD,” said Dr. Sheehan and collaborators.
Scores on the Sheehan Disability Scale, used to assess social, family, and work/school functioning, improved significantly more for those on vilazodone than placebo, both for total score and for all domain subscores (total SDS score difference -1.89, P = 0.02).
Scores on two clinician rating tools, the Clinical Global Impression–Global Improvement (CGI-I) and the Clinical Global Impression–Severity (CGI-S) also improved significantly by least squares mean when vilazodone was compared with placebo (P = 0.003 and P = 0.0003, respectively).
Men taking vilazodone were more likely than those taking placebo to report sexual function-related adverse events, though overall numbers were low, and they also saw a small mean decrease on a sexual functioning questionnaire. These differences were not seen for women taking vilazodone, who reported a small improvement in sexual function, as did both men and women taking placebo.
There were no deaths and no serious abnormalities in laboratory values or ECGs in either group. Of the 404 evenly divided patients included in the safety analysis, significantly more patients discontinued vilazodone (58 patients, 28.7%) than discontinued placebo (39 patients, 19.3%, P < 0.05). Further, 22 patients (10.9%) stopped taking vilazodone because of adverse events, compared with 4 patients (2.0%) taking placebo (P < 0.05).
The most common treatment-emergent adverse event for the vilazodone group was nausea, occurring in 60 patients (29.7%), compared with 26 (12.9%) of the placebo group.
Forest Laboratories, an affiliate of Actavis, funded the study. Dr. Sheehan reported multiple financial affiliations with pharmaceutical companies, including Actavis and Forest Laboratories. All other authors are employees of Forest Research Institute.
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