A 28-Week, Randomized, Double-Blind Study of Olanzapine Versus Aripiprazole in the Treatment of Schizophrenia

Objective: To evaluate the effectiveness of olanzapine versus aripiprazole in patients with schizophrenia. Method: Patients aged 18 to 65 years with schizophrenia (diagnosed according to DSM-IV-TR criteria) were randomly assigned to either olanzapine (n = 281) or aripiprazole (n = 285) for 28 weeks of double-blind treatment. The primary outcome was time to all-cause discontinuation. Efficacy was measured by Positive and Negative Syndrome Scale (PANSS) total change from baseline. Time-to-event data were analyzed via the Kaplan-Meier method. The study was conducted from October 2003 to July 2007. Results: Treatment groups did not differ significantly in time to all-cause discoutinuation (p = .067) or all-cause discontinuation rate (olanzapine, 42.7% vs. aripiprazole, 50.2% p = .053). Olanzapine-treated patients had significantly longer time to efficacy-related discontinuation (p < .001) and a significantly lower efficacy-related discontinuation rate (olanzapine, 8.9% vs. aripiprazole, 16.8%; p = .006). Olanzapine-treated patients had a significantly greater mean decrease (last observation carried forward) in PANSS total score (-30.2) than did aripiprazole-treated patients (-25.9, p = .014). Olanzapine-treated patients had a mean weight change of +3.4 kg (vs. +0.3 ka for aripiprazole-treated patients; p < .001) and a significantly greater incidence of >= 7% body weight gain at any time (40.3% vs. 16.4%: p < .001). Fasting mean glucose change was +4.87 mg/dL for olanzapine and +0.90 mg/dL for aripiprazole (p = .045). Incidence of baseline glucose < 100 mg/dL and > 126 mg/dL at any time was 1.7% for olanzapine and 0.6% for aripiprazole (p = .623). Fasting mean total cholesterol change was +4.09 mg/dL for olanzapine and -9.85 mg/dL for aripiprazole (p < .001). Incidence of baseline total cholesterol < 200 mg/dL and 240 mg/dL, at any time was 9.2% for olanzapine and 1.5% for aripiprazole (p = .008). Fasting mean triglycerides change was +25.66 mg/dL for olanzapine and -17.52 mg/dL for aripiprazole (p < .001). Treatment groups did not significantly differ on measures of extrapyramidal symptoms. Conclusion: Treatment groups did not differ significantly on the primary outcome. Olanzapine-treated patients had significantly greater improvement in symptom efficacy at 28 weeks as well as significantly greater mean increases in weight and glucose and significantly greater worsening on lipids parameters.