Background: Bipolar disorder, a highly recurrent and chronic condition, often necessitates periods of hospitalization and requires lifelong treatment with medication. It is characterized by alternating episodes of mania and depression. Given the severity of mania, physicians must be able to control symptoms rapidly.
Objective: The purpose of this pivotal, Phase III trial was to evaluate the efficacy and tolerability of once-daily extended-release quetiapine fumarate (quetiapine XR) monotherapy in improving manic symptoms in patients with bipolar I disorder.
Methods: This was a 3-week, randomized, parallel-group, double-blind, placebo-controlled study. Patients aged 18 to 65 years with bipolar I disorder (most recent episode manic or mixed; with or without rapid cycling) were randomized to receive placebo or quetiapine XR monotherapy once daily (300 mg on day 1; 600 mg on day 2; flexible dosing, 400-800 mg, from day 3 through day 22 [study end point, week 3]). The primary outcome measure was the change from baseline to study end in the Young Mania Rating Scale (YMRS) total score. Secondary outcome measures included the Montgomery-Åsberg Depression Rating Scale (MADRS) total score, YMRS response (≥50% reduction in YMRS) and remission (YMRS score ≤12 at final visit) rates, and change from baseline to week 3 in Clinical Global Impression-Bipolar-Severity of Illness (CGI-BP-S) and CGI-BP-Change (CGI-BP-C) scores. Safety profile and tolerability evaluations included monitoring of adverse events, clinical laboratory values, vital signs, extrapyramidal symptoms (including akathisia), and electrocardiogram results.
Results: Compared with placebo (n = 159), quetiapine XR monotherapy (n = 149; mean daily dose, 604 mg) significantly improved manic symptoms starting at day 4 (first assessment; P < 0.001), with sustained improvement to study end (week 3; P < 0.001). MADRS scores showed greater improvement from baseline to study end with quetiapine XR than with placebo (P = 0.004). Response and remission rates were significantly greater (P < 0.01) with quetiapine XR than with placebo at study end. Quetiapine XR also resulted in significant improvements over placebo in CGI-BP-S and CGI-BP-C scores (P < 0.001 and P < 0.001, respectively). Adverse events were mild to moderate in intensity; the most common ones associated with quetiapine XR were sedation, dry mouth, and somnolence.
Conclusion: This 3-week trial suggests that quetiapine XR (400-800 mg) once-daily monotherapy is efficacious (from day 4) and generally well tolerated in patients with manic or mixed episodes of bipolar I disorder.
Trial registration: ClinicalTrials.gov NCT00422123.
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