Abstract
OBJECTIVE: To evaluate the efficacy and tolerability of adjunct extended release quetiapine fumarate (quetiapine XR) in patients with generalized anxiety disorder (GAD) and inadequate response to selective serotonin reuptake inhibitors/ serotonin norepinephrine reuptake inhibitors (SSRI/SNRIs). METHODS: 11-week (1-week single-blind placebo run-in; 8-week randomized treatment; 2-week post-treatment period), double-blind, placebo-controlled study. Patients were randomized to quetiapine XR or placebo adjunct to SSRI/SNRI. 50 mg initial dose; 150 mg/day, Day 3; 300 mg/day, Weeks × and 4 if indicated (Clinical Global Impressions-Severity of Illness [CGI-S] ≥ 4; 150 mg/day tolerated). Primary endpoint: change from randomization to Week 8 in HAM-A total score. Secondary variables: Hamilton Rating Scale for Anxiety (HAM-A) psychic/somatic clusters, response and remission; and CGI-S. RESULTS: 409 patients were randomized to quetiapine XR (n = 209) or placebo (n = 200); 41% and 55% of patients, respectively, had dose increases (300 mg/day). Week 8 mean change in HAM-A total score was not statistically significant for quetiapine XR (-10.74; p = 0.079) versus placebo (-9.61). Secondary variables were generally consistent with the primary analysis, except a significant reduction in HAM-A total score at Week 1 (-6.45, quetiapine XR versus -4.47, placebo; p < 0.001); significant improvements in HAM-A psychic cluster (p < 0.05) and CGI-S total (p < 0.05) scores at Week 8. Adverse events (.10% either group) were dry mouth, somnolence, sedation, headache, and dizziness. CONCLUSIONS: In patients with GAD and inadequate response to SSRI/SNRI, adjunct quetiapine XR did not show a statistically significant effect for the primary endpoint at Week 8, although some secondary endpoints were statistically significant versus placebo. Quetiapine XR was generally well tolerated.