Quetiapine for the treatment of bipolar II depression: Analysis of data from two randomized, double-blind, placebo-controlled studies

Objective: To investigate the efficacy and tolerability of quetiapine monotherapy for depressive episodes in patients with bipolar II disorder. Methods: A post-hoc evaluation was conducted in 351 patients with bipolar II depression combined from two similarly designed double-blind, randomized, placebo-controlled, 8-week studies of quetiapine (300 or 600mg/day) that included patients with bipolar I or II disorder (DSM-IV) exhibiting moderate to severe depression. The primary endpoint was change from baseline to week 8 in MADRS total score. Secondary endpoints included HAM-D, HAM-A, and CGI. Results: In patients with bipolar II disorder, improvement in mean MADRS total score from baseline was significantly greater with quetiapine 300 (n = 107) and 600mg/day (n = 106) from the first assessment (week 1) through week 8 compared with placebo (n = 108). The mean change from baseline at week 8 for quetiapine 300 and 600mg/day versus placebo was -17.1 and -17.9 versus -13.3 (P = 0.005 and P = 0.001 versus placebo), respectively. Change in HAM-D, HAM-A, and CGI were also significantly greater for quetiapine groups versus placebo. Common adverse events in the quetiapine groups included dry mouth, sedation, and somnolence. Conclusion: Quetiapine demonstrated significant efficacy as monotherapy, compared with placebo, for the treatment of acute depressive episodes in bipolar II disorder.