Efficacy of olanzapine monotherapy in the treatment of bipolar depression with mixed features.

Background: This analysis investigated the correlations between the efficacy of olanzapine monotherapy and the number of concurrent manic symptoms in patients treated for bipolar depression.

Methods: Pooled data from 2 placebo-controlled olanzapine studies in patients with bipolar I depression were analyzed (total 1214 patients; 690 olanzapine monotherapy patients and 524 placebo patients). Patients were categorized for mixed features by the number of concurrent manic symptoms at baseline (0, 1 or 2, and ≥3, respectively, as measured by a Young Mania Rating Scale item score ≥1). Efficacy was evaluated by change in Montgomery-Åsberg Depression Rating Scale (MADRS) total score from baseline to 6 weeks.

Results: Least-squares mean differences between olanzapine and placebo in the change of MADRS total scores were -3.76 (p=0.002), -3.20 (p<0.001), and -3.44 (p=0.002) for mixed features 0, 1 or 2, and ≥3, respectively. The response rates for olanzapine versus (vs.) placebo were 52.6% vs. 39.8%, 50.3% vs. 40.0%, and 42.2% vs. 33.7% for mixed features 0, 1 or 2, and ≥3, respectively. The remission rates for olanzapine vs. placebo group were 46.1% vs. 34.3%, 39.5% vs. 32.0%, and 34.8% vs. 24.1% for mixed features 0, 1 or 2, and ≥3, respectively. No significant interaction between mixed features and treatment was seen in the MADRS changes or response and remission rates.

Limitations: Post hoc analyses of the data from 2 previous randomized clinical studies.

Conclusions: Olanzapine monotherapy was shown to be effective in the treatment of bipolar depression irrespective of the presence of concurrent manic symptoms.