NEW YORK (Reuters Health) - The investigational atypical antipsychotic bifeprunox appears to have fewer metabolic side effects than currently used drugs for schizophrenia.

That's according to safety analyses of previously reported mid- and late-stage clinical studies of bifeprunox in patients with schizophrenia presented Friday at the International Congress on Schizophrenia Research in Colorado Springs.

In a telephone interview with Reuters Health, Dr. Herbert Y. Meltzer said: "When you look at the data in aggregate, comparing to placebo and to active comparators, it looks like bifeprunox is going to be a very tolerable atypical antipsychotic drug -- and that goes right through all the key dimensions from extrapyramidal side effects, prolactin elevations, weight gain, and various measures of lipids."

"What I can glean from the individual studies and the composite data is that, on average, there isn't any significant weight gain, increase in lipids or signs of glucose dysregulation," said Dr. Meltzer. "After switching to bifeprunox, there was actually a decrease in weight, prolactin, and triglycerides," he noted.

Dr. Meltzer is director of the division of psychopharmacology at Vanderbilt University, Nashville, Tennessee and has been involved in bifeprunox studies.

Bifeprunox is being developed jointly by Solvay Pharmaceuticals Inc., Wyeth Pharmaceuticals, and Lundbeck A/S of Denmark. Solvay filed the NDA on bifeprunox with the US Food and Drug Administration in October 2006.

In previously reported efficacy studies, bifeprunox improved symptoms in patients with acute exacerbations of schizophrenia but showed a smaller mean effect than did active comparators (risperidone and olanzapine) versus placebo. It also helped prevent deterioration in schizophrenia patients whose symptoms were already under control.

"If approved, bifeprunox may be an important alternative for treating adult patients with schizophrenia over the long term," Dr. Meltzer said in a statement, "particularly because of our concerns about the high prevalence of metabolic syndrome in this patient population."