Number needed to treat and time to response/remission for quetiapine monotherapy efficacy in acute bipolar depression: evidence from a large, randomized, placebo-controlled study

The objectives of this analysis are to elucidate the clinical significance of antidepressant effects with quetiapine by evaluating number needed to treat as well as time to response and remission with quetiapine monotherapy in patients with acute bipolar depression. A post-hoc analysis was conducted of 542 patients with bipolar I or II disorder, (moderate to severe depression), randomized to 8 weeks of double-blind treatment with quetiapine 600 mg/day (n=180), quetiapine 300 mg/day (n=181), or placebo (n=181). Number needed to treat, time to response (> or =50% reduction from baseline in Montgomery-Asberg Depression Rating Scale total score) and time to remission (Montgomery-Asberg Depression Rating Scale total score < or =12) were evaluated. Response rates at week 8 were 58.2 and 57.6% for quetiapine 600 and 300 mg/day, respectively, and 36.1% for placebo (P<0.001). Remission rates were 52.9% for both quetiapine groups and 28.4% for placebo (P<0.001). The number needed to treat was five for both response and remission for quetiapine (600 and 300 mg/day) compared with placebo. Median time to response and remission were significantly shorter with quetiapine 600 and 300 mg/day than placebo. No between-group difference was found in the incidence of treatment-emergent mania or hypomania (quetiapine 600 mg/day: 2.2%, quetiapine 300 mg/day: 3.9, and placebo: 3.9%). In conclusion, quetiapine compared with placebo significantly reduces time to response and remission compared with placebo, and has a favorable number needed to treat.