Efficacy and safety of adjunctive oral ziprasidone for acute treatment of depression in patients with bipolar I disorder: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE

To assess efficacy and safety of adjunctive ziprasidone in subjects with bipolar depression treated with lithium, lamotrigine, or valproate.

METHOD: 298 adult outpatients with bipolar I disorder (DSM-IV criteria) were randomized to receive ziprasidone, 20-80 mg twice a day, or placebo twice a day for 6 weeks plus their preexisting mood stabilizer. The primary efficacy variable was change in Montgomery-Asberg Depression Rating Scale (MADRS) total scores from baseline to 6 weeks. The key secondary efficacy endpoint was change from baseline to week 6 in Clinical Global Impressions-Severity (CGI-S) scores. Computer-administered assessments for diagnostic confidence were included for quality control and to evaluate study performance. The study was conducted between October 2007 and December 2008.

RESULTS

The mean ± SD daily dose of ziprasidone was 89.8 ± 29.1 mg. Least squares mean ± standard error changes from baseline to week 6 on MADRS total score for ziprasidone and placebo treatment groups were -13.2 ± 1.2 and -12.9 ± 1.1, respectively, with a 2-sided P value of .792. There was no significant difference on the key secondary variable (CGI-S). Adjunctive ziprasidone was well tolerated. Poor quality ratings at baseline were associated with a trend for better improvement on placebo than ziprasidone. Among 43 placebo-treated subjects with poor baseline quality ratings, 29 (67.4%) had baseline MADRS scores > 10 points higher on the computer-administered assessment than the MADRS administered by the site-based rater. The response favoring placebo over ziprasidone observed in this subgroup suggests that poor signal detection in some clinical trials can be a consequence of "subject inflation" as well as "rater inflation."

CONCLUSIONS

Adjunctive ziprasidone treatment failed to separate from mood stabilizer alone on primary and secondary endpoints. Possible contributions to this result include enrollment of a substantial number of subjects with low diagnostic confidence, low quality ratings on the MADRS, and overzealous reporting of symptoms by subjects.

TRIAL REGISTRATION: clinical trials.gov Identifier: NCT00483548.