The Phase III study evaluated the efficacy of iloperidone versus placebo in patients with schizophrenia. The study was a randomized, double-blind, placebo-controlled, multi-center, four-week inpatient study that enrolled 604 patients. Following fixed-dose titration, inpatients were randomized to receive iloperidone at 24mg/day, ziprasidone at 160mg/day, or placebo. Patients treated with iloperidone had significantly greater improvements in positive and negative syndrome scale-total (PANSS-T) scores than those on placebo, and had PANSS-T improvement comparable to ziprasidone.
Iloperidone and ziprasidone showed similarly low effects on glucose, cholesterol, triglyceride and prolactin levels compared to placebo. Iloperidone also had a similar akathisia profile to placebo, whereas ziprasidone was associated with a worsening of akathisia versus placebo on the barnes akathisia scale (BAS), with 26% of patients experiencing a worsening of akathisia. Iloperidone was also associated with a favorable profile on the extrapyramidal symptoms rating scale (ESRS) versus placebo.