Assessments of Suicidality in Double-Blind, Placebo-Controlled Trials of Ziprasidone

Objective: A pooled analysis was conducted to identify possibly suicide-related adverse events in Pfizer-sponsored, phases 2-4, placebo-controlled, double-blind, adult and pediatric completed randomized controlled trials of ziprasidone and to evaluate the risk of suicidality with ziprasidone versus placebo.

Method: The trials included were initiated as early as June 1992, and the cutoff date for selection of the placebo-controlled trials in the Pfizer database was October 2, 2009. The US Food and Drug Administration (FDA)-defined search methodology was used to identify possibly suicide-related adverse events, and the Columbia Classification Algorithm of Suicide Assessment (primary outcome measure) was used to categorize them. The incidences of possibly suicide-related adverse events were calculated for individual classifications and for the predefined combined categories of suicidality (comprising classification codes 1-4) and suicidal behavior (comprising classification codes 1-3), along with the ziprasidone versus placebo relative risks and corresponding 95% CIs. Exact binomial 95% CIs were calculated for the individual treatment group incidences.

Results: Suicidality events were identified in 52 among 5,123 subjects treated with either ziprasidone or placebo in 22 trials. No cases of completed suicide occurred in this analysis. There were no statistically significant differences between ziprasidone and placebo in any of the individual classification categories, combined suicidal behavior category (ziprasidone vs placebo relative risk = 0.67; 95% CI, 0.206-2.201), or combined suicidality risk category (ziprasidone vs placebo relative risk = 0.90; 95% CI, 0.514-1.563).

Conclusions: Results of our analyses, performed in accordance with the FDA-specified search strategy, reveal no significant differences in treatment-emergent suicidality risk in ziprasidone versus placebo subjects treated in controlled clinical trials.

J Clin Psychiatry 2011;72(3):367-375

Submitted: May 26, 2010; accepted December 9, 2010

(doi:10.4088/JCP.10m06281gre).

Corresponding author: Onur N. Karayal, MD, MPH, Pfizer Inc, 235 East 42nd St, New York, NY, 10017 (Onur.Karayal@pfizer.com).