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Saturday 13 August 2005

Long-Term Study Shows Pfizer's Geodon Has Comparable Efficacy With Fewer Adverse Metabolic Effects Than Zyprexa

By: Schizophrenia News

The antipsychotic Geodon® (ziprasidone HCl) is as effective as Zyprexa (olanzapine) in maintenance treatment of patients with schizophrenia, but has significantly less adverse effect on body weight, cholesterol, and insulin, according to results from a six-month, double-blind, head-to-head study published in the current issue of the American Journal of Psychiatry.

These study results come amidst concern that some second-generation antipsychotics (SGAs) can cause weight gain and metabolic adverse events -- including raised cholesterol and insulin levels -- which can increase patients' risks for obesity, diabetes and cardiovascular disease.

“Geodon's equal long-term efficacy but lack of metabolic adverse effects are important advantages over Zyprexa,” said lead author and investigator George Simpson, M.D., professor of research psychiatry and interim chair, Keck School of Medicine of the University of Southern California. “Given that patients often take antipsychotic medications for many years, it's important for physicians to consider potential long-term risks, such as cardiovascular disease and diabetes, when selecting the best treatment.”

Study and Findings

In this continuation study, 126 patients with schizophrenia or schizoaffective disorder given flexibly dosed Geodon or Zyprexa demonstrated comparable responses on standard measures of schizophrenia symptoms at six months (85.5 percent for ziprasidone and 84.5 percent for olanzapine), maintaining improvements seen in the core six-week trial.

However, patients taking Zyprexa had significant increases versus baseline in average body weight (+11 lbs) compared with a mean weight loss of -1.8 pounds for patients on Geodon. Zyprexa patients also experienced significant increases from baseline in total cholesterol (+13.0 mg/dL), low-density lipoprotein cholesterol (+17.0 mg/dL) and fasting insulin (+2.0 µU/mL); there were no significant changes seen with Geodon.

The frequency of treatment-related adverse events (mostly mild to moderate) was similar in the Geodon and Zyprexa groups (58.2 percent and 66.2 percent, respectively). The most common treatment-related adverse events were of the nervous system (50.9 percent for Zyprexa and 46.5 percent for Geodon) and digestive system (27.3 percent for Zyprexa and 22.5 percent for Geodon). More adverse events related to metabolic adverse effects and weight gain were seen in Zyprexa patients vs. Geodon patients (21.8 percent vs 3.6 percent, respectively).

This study was a double-blinded extension of an initial, six-week trial in 269 patients, which also showed equivalent efficacy for the two SGAs. Patients who responded to Geodon (n=55) and Zyprexa (n=71) in the initial study were enrolled in the six-month extension. Primary efficacy measures included scores on the Brief Psychiatric Rating Scale (BPRS) and Clinical Global Impression-Severity (CGI-S); other efficacy measures included scores on Positive and Negative Syndrome Scale (PANSS) and the Calgary Depression Scale for Schizophrenia (CDSS).

Schizophrenia and Metabolic Disorders

Individuals with schizophrenia have a 20 percent shorter life expectancy than the population at large and a greater vulnerability to several illnesses, including diabetes, coronary heart disease, hypertension, and emphysema. These increased risks are partly due to lifestyle factors, including poor dietary habits, high rates of smoking, and the use of alcohol and street drugs. In addition, while SGAs represent a major advance in the management of schizophrenia, some are associated with significant increases in body weight and blood levels of triglycercides, cholesterol and insulin - all of which can increase the risk for diabetes and cardiovascular disease.

However, according to a consensus statement by the American Diabetes Association, American Psychiatric Association and other health organizations, Geodon is associated with little or no significant risk of weight gain, diabetes, or dyslipidemia, although it has not been used as extensively as other agents. Additionally, studies show that patients who switched from some other SGAs to Geodon showed substantial weight loss, as well as improvements in cholesterol and triglycerides.

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