The primary objective of this trial was to characterize the long-term (up to 40 weeks) safety and tolerability of asenapine in bipolar I disorder subjects who had not completely responded to continuing treatment with lithium or valproic acid (VPA) for the treatment of an acute manic or mixed episodes upon enrollment into the 12-week lead-in trial, A7501008 (NCT00145470). The safety comparison was between the group receiving lithium or VPA and placebo against the group receiving lithium or VPA and asenapine, with the caveat that all subjects may have received benzodiazepine and/or antidepressant rescue medication as needed.