Efficacy and tolerability of extended release quetiapine fumarate (quetiapine XR) monotherapy in major depressive disorder: a placebo-controlled, randomized study.

Background: Evaluate the efficacy and tolerability of extended release quetiapine fumarate (quetiapine XR) once-daily monotherapy for patients with major depressive disorder (MDD).

Methods: In this 10-week, (8-week active treatment phase and 2-week drug-discontinuation/tapering phase), multicenter, parallel-group, placebo-controlled, double-blind, randomized, Phase III study (D1448C00003: Opal), patients initially received quetiapine XR 150 mg/day or placebo. At Week 2, inadequate responders (<20% reduction in MADRS total score) were up-titrated to 300 mg/day quetiapine XR or matching placebo for the final 6 weeks. Primary endpoint: change from randomization to Week 8 in MADRS total score. Secondary endpoints included: MADRS response (≥50% reduction in total score from randomization) and changes from randomization to Week 8 in HAM-D and CGI-S.

Results: 310 patients were randomized. At Week 8, quetiapine XR significantly reduced mean MADRS total score versus placebo (-16.49 vs -13.10, respectively; p<0.01). Mean MADRS score was significantly reduced by quetiapine XR versus placebo at Week 1 (p<0.05). MADRS response rates were significantly greater at Week 8 for quetiapine XR versus placebo (61.9% vs 48.0%, respectively; p<0.05). Significant changes in HAM-D total score and CGI-S were seen at Week 8 for quetiapine XR versus placebo. Withdrawal rates due to AEs were 9.9% and 2.6% for quetiapine XR and placebo, respectively. Common AEs (>10% any group during the randomized phase) for quetiapine XR and placebo, respectively were dry mouth (32.9% and 6.5%), sedation (21.7% and 1.9%), somnolence (20.4% and 5.2%), and headache (10.5% and 10.3%).

Limitations: The study was not designed to compare quetiapine XR 150 mg/day and 300 mg/day; it was intended to reflect dose titration that might occur in clinical practice.

Conclusions: Quetiapine XR monotherapy is effective in patients with MDD, with symptom improvement seen as early as Week 1, and tolerability results consistent with the known profile of quetiapine.