A randomized, double-blind, placebo-controlled study of rapid-acting intramuscular olanzapine in Japanese patients for schizophrenia with acute agitation

Abstract

Background: Olanzapine rapid-acting intramuscular (IM) injection is an atypical antipsychotic drug already used overseas and recently approved in Japan. The objective of this study was to confirm the efficacy of rapid-acting IM olanzapine 10 mg was greater than IM placebo in patients with exacerbation of schizophrenia with acute psychotic agitation by comparing changes from baseline to 2 hours after the first IM injection, as measured by the Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) total score.Methods: We conducted a placebo-controlled, randomized, double-blind, parallel-group study in Japanese patients diagnosed with schizophrenia according to the diagnostic criteria specified in the DSM-IV-TR. Patients were randomized to 2 treatment groups: IM olanzapine (10 mg) or IM placebo. The primary efficacy outcome was the change in PANSS-EC from baseline to 2 hours after the first IM injection. Treatment groups were compared with an analysis of variance model which included treatment and site as factors. During the 24-hour treatment period, safety was assessed by clinical examination and laboratory investigations, electrocardiograms, extrapyramidal symptoms scales, and recording spontaneously reported adverse events.Results: Of the 91 randomized patients, 90 patients (45 IM olanzapine-group; 45 IM placebo-group) were in the full analysis set. The mean change of PANSS-EC total score from baseline to 2 hours after the first IM injection (mean±standard deviation) was -9.2±4.5 for the IM olanzapine group and -2.8±5.6 for the IM placebo group. The difference between treatment groups was statistically significant (p