10-week (8-week active treatment, randomised phase; 2-week post-treatment drug-discontinuation/tapering phase), multicentre, double-blind, placebo-controlled, parallel-group comparison with paroxetine study (D1448C00011). 873 patients were randomised to receive quetiapine XR 50mg/day (n=221), 150mg/day (n=218), paroxetine 20mg/day (n=217) or placebo (n=217). Primary endpoint: change from baseline to Week 8 in HAM-A total score. Secondary outcomes included: change from baseline to Week 8 in HAM-A psychic and somatic clusters.
Mean HAM-A total score (overall baseline mean, 26.98) was significantly reduced at Week 8 by quetiapine XR 50mg/day (-13.95, p<0.05), 150mg/day (-15.96, p<0.001) and paroxetine (-14.45, p<0.01) versus placebo (-12.30).
At Week 8, mean HAM-A psychic cluster score (overall baseline mean, 14.40) was significantly reduced by quetiapine XR 50mg/day (-7.42, p<0.01), 150mg/day (-8.64, p<0.001) and paroxetine (-7.70, p<0.001) versus placebo (-6.27). Mean HAM-A somatic cluster score (overall baseline mean, 12.58) was significantly reduced by quetiapine XR 150mg/day (-7.37, p<0.001) versus placebo (-6.00), but not quetiapine XR 50mg/day (-6.54, p=0.15) or paroxetine (-6.74, p=0.05).
The incidence of serious AEs was low (<2%) in all treatment groups. During Weeks 1-8, most common AEs (>10%) were dry mouth, somnolence, fatigue, dizziness and headache with quetiapine; headache with placebo; and somnolence, dizziness, headache and nausea with paroxetine.
Once-daily oral treatment with quetiapine XR (50 and 150mg/day) was well tolerated and significantly reduced anxiety symptoms, demonstrating effects on both somatic and psychic symptoms, in patients with GAD.