A randomized, double-blind study of once-daily extended release quetiapine fumarate (quetiapine XR) monotherapy in patients with generalized anxiety disorder

This study evaluated once-daily, extended-release quetiapine fumarate (quetiapine XR) monotherapy in generalized anxiety disorder (GAD). This was a 10-week (8-week active treatment/2-week posttreatment drug-discontinuation/tapering phase), double-blind, randomized, placebo-controlled study (D1448C00009). Primary end point was change from randomization at week 8 in Hamilton Anxiety Rating Scale (HAM-A) total score. Overall, 951 patients with GAD were randomized (quetiapine XR: 50 mg/d, n = 234; 150 mg/d, n = 241; 300 mg/d, n = 241; placebo, n = 235). At week 8, HAM-A total scores significantly (P < 0.001) improved versus placebo (-11.10) with quetiapine XR 50 mg/d (-13.31) and 150 mg/d (-13.54), but not 300 mg/d (-11.87; P = 0.240). At week 1, HAM-A total scores significantly improved versus placebo (-5.94) with quetiapine XR 50 mg/d (-7.47; P < 0.01), 150 mg/d (-8.19; P < 0.001), and 300 mg/d (-7.23; P < 0.01). Versus placebo at week 8, quetiapine XR 50 and 150 mg/d significantly improved HAM-A psychic (P < 0.01 and P < 0.001, respectively) and somatic (P < 0.001; P < 0.01, respectively) cluster scores, HAM-A response (≥ 50% total score reduction; P < 0.05), and Clinical Global Impression-Improvement categorical changes (P < 0.05). For quetiapine XR 150 mg/d, significant (P < 0.05) improvements were seen for HAM-A remission (total score, ≤ 7) and Clinical Global Impression-Severity of Illness scores. For quetiapine XR 300 mg/d, improvements in these secondary variables were not significantly different versus placebo. Pittsburgh Sleep Quality Index global scores improved with all 3 doses (quetiapine: XR 50 mg/d, -4.07 [P < 0.05]; 150 mg/d, -4.38 [P < 0.05]; 300 mg/d, -3.97 [P < 0.05], versus -3.31 with placebo). Adverse events (>10% with quetiapine XR) were dry mouth, somnolence, sedation, dizziness, headache, and fatigue. Quetiapine XR (50/150 mg/d) monotherapy was effective at week 8 in patients with GAD; symptom improvement was seen at week 1 for all doses (50/150/300 mg/d). Safety and tolerability were consistent with the known profile of quetiapine.