Efficacy of once-daily extended release quetiapine fumarate in patients with different levels of severity of generalized anxiety disorder

This study is a pooled, post-hoc analysis evaluating once-daily extended release quetiapine fumarate (quetiapine XR) monotherapy in patients with generalized anxiety disorder (GAD). Three previously reported positive, 8-week, randomized, double-blind, placebo-controlled studies evaluated quetiapine XR therapy (50, 150, 300 mg/day) in patients with GAD [Hamilton Anxiety Rating Scale (HAM-A) total score≥20]. Patients were stratified by baseline severity: HAM-A total score ≥22, ≥24, <26, ≥26, ≥28. We report HAM-A total score change, response (≥50% reduction in HAM-A total score), and remission (HAM-A total score⩽7 and ⩽9). Quetiapine XR significantly improved HAM-A total scores compared with placebo at Weeks 1 and 8 in the HAM-A ≥22, ≥24, and ≥26 cohorts (all doses), at Week 1 (all doses) and Week 8 (quetiapine XR 150 mg/day) in the <26 cohort, and at Week 1 (all doses) and Week 8 (quetiapine XR 50 and 150 mg/day) in the HAM-A≥28 group (P<0.05). Week 8 effect sizes for 50, 150, and 300 mg/day were as follows: 0.29, 0.47, 0.17 (HAM-A≥22); 0.35, 0.55, 0.22 (HAM-A≥24); 0.18, 0.32, 0.10 (HAM-A<26); 0.41, 0.59, 0.24 (HAM-A≥26); 0.60, 0.64, 0.22 (HAM-A≥28), respectively. Acute quetiapine XR monotherapy significantly improves anxiety compared with placebo in patients with moderate or severe GAD, with symptom improvements seen as early as Week 1.