Effectiveness of the extended release formulation of quetiapine as monotherapy for the treatment of acute bipolar depression.

Background: To evaluate the effectiveness of quetiapine extended release once daily in bipolar depression.

Methods: Double-blind, placebo-controlled study in acutely depressed adults with bipolar I or II disorder, with or without rapid cycling. Patients were randomized to 8 weeks of quetiapine extended release (XR) 300 mg daily monotherapy or placebo. The primary outcome measure was change from baseline to Week 8 in MADRS total score.

Results: Quetiapine XR 300 mg once daily (N=133) showed significantly greater improvement in depressive symptoms compared with placebo (N=137) from Week 1 (p<0.001) through to Week 8 (p<0.001). Mean change in MADRS total score at Week 8 was -17.4 in the quetiapine XR group and -11.9 in the placebo group (p<0.001). Response (>or=50 reduction in MADRS total score) and remission (MADRS total score
Limitations: Fewer patients with bipolar II disorder included, only one fixed dose tested and the lack of an active comparator.

Conclusions: Quetiapine XR (300 mg) once daily monotherapy was significantly more effective than placebo for treating episodes of depression in bipolar I disorder, throughout the 8-week study, with significance observed as early as Day 7. Adverse events were consistent with the known effects of quetiapine.