Quetiapine is approved for the treatment of acute mania and depression associated with bipolar disorder, a complex and debilitating illness that has a lifetime prevalence between 1% to 4% in the US [Bowden CL et al. J Clin Psychiatry 2005]. The antipsychotic benefits of quetiapine are thought to derive from its ability to block the dopamine and serotonin type 1 and 2 receptors.

Data from several posters that were presented during the APA annual meeting showed the superiority of extended release quetiapine as a treatment for major depressive disorder (MDD) and generalized anxiety disorder (GAD) associated with bipolar I/II disorders (BP I, II) versus placebo in patients aged 18 to 65 years.

Cutler A et al. (NR3–006) reported that quetiapine (400–800 mg/day) significantly (p<0.01) reduced the Young Mania Rating Scale (YMRS) score versus placebo after 3 weeks in BP I patients (−14.34 and −10.52, respectively; p<0.001).

Brecher M et al. (NR3–077) presented data from two time-to-event studies that used quetiapine (400–800 mg/day) as adjunctive therapy to lithium or divalproex in BP I patients. Time from randomization to a mood event (mania, depression, or mixed) was significantly extended (p<0.001) with adjunctive quetiapine versus lithium/divalproex+placebo (HR=0.30; 95% CI 0.24, 0.37); 125/646 (19.3%) of quetiapine patients and 343/680 (50.4%) of placebo patients experienced a mood event within the 104-week studies.

In a similar study in MDD patients, Datto C et al. (NR3–017) reported that quetiapine (mean 176.6 ± 95.5 mg/day) significantly (p<0.001) extended the time to a depressive event (HR=0.34; 95% CI 0.25, 0.46); 55/387 (14.2%) of quetiapine and 132/384 (34.4%) of placebo patients experienced a depressive event within the 52-week study.

Weisler R et al. (NR3–101) reported that in patients with MDD, MADRS scores were significantly (p<0.001) reduced by quetiapine 50 mg (−13.56), 150 mg (−14.50), and 300 mg (−14.18) versus placebo (−11.07) after 8 weeks of treatment.

Similar findings were presented by Suppes T et al. (NR3–124) in BP I & II patients with and without rapid cycling (n=270) who experienced acute depression. After 8 weeks, the mean change in MADRS total score for quetiapine (300 mg/day) was −17.4 versus −11.9 in the placebo group (p<0.001).

Joyce M et al. (NR3–138) reported that quetiapine 50 and 150 mg/day, but not 300 mg/day, significantly (p<0.001) reduced GAD scores (HAM-A) after 8 weeks.

In a time-to-event study, Katzman M et al. (NR3–140) noted that quetiapine (50–300 mg/day) significantly (p<0.0001) extended the time to a reoccurrence of a GAD-related event versus placebo (HR =0.19; 95% CI 0.12, 0.31); 22/216 (10.2%) quetiapine- and 84/217 (38.9%) placebo-treated patients experienced a GAD-related event within the 52-week study.

The most common adverse events that were reported with quetiapine were sedation, dry mouth, somnolence, dizziness, headache, fatigue, and weight increase. The authors of these studies concluded that quetiapine offers a safe and well-tolerated treatment for mood disorders that are associated with bipolar disorder in a wide class of individuals.