Asenapine appears to be effective and safe as short-term treatment for mania associated with bipolar I disorder, according to a presentation at the annual meeting of the American Psychiatric Association.

Asenapine, a fast-dissolving, novel psychopharmacologic agent with a unique human receptor signature, was shown to be effective in two short-term bipolar mania studies with a nine-week extension. Overall, asenapine was well tolerated.

"Despite having effective treatments available, up to 75 percent of schizophrenia patients and many bipolar disorder patients stop taking their medicines because of unwanted side effects or lack of efficacy," said Roger McIntyre, MD, Associate Professor of Psychiatry and Pharmacology at the University of Toronto and head of the Mood Disorders Psychopharmacology Unit at the University Health Network, Toronto, Canada.

"Therefore, new therapies that are both effective and well-tolerated would be welcome additions to the treatment options currently available for improving patient care."

The asenapine Olympia clinical trial program thus far has involved over 3,000 patients and has included bipolar mania and acute schizophrenia.

The bipolar I disorder program included two placebo- and active-controlled, three-week trials followed by an extension study totaling one year of treatment; nearly 1,000 patients with bipolar I disorder were involved.

Treatment response was measured using the Young Mania Rating Scale (YMRS) score, an 11-item scale used to evaluate manic symptoms.

In the trials, both asenapine and the active-control drug olanzapine produced greater mean reductions in YMRS total scores versus placebo after three weeks of treatment. Asenapine produced 13- and 14-point reductions in the YMRS total score from baseline to day 21 (significant compared with placebo; olanzapine was also statistically superior to placebo; there was no direct comparison between asenapine and olanzapine).

In a nine-week extension of the three-week trials, asenapine was found to be noninferior to olanzapine on the primary efficacy measure, change in YMRS.

The overall incidence of treatment-related adverse events in the trials was 60.8 percent in the asenapine group, 52.9 percent in the olanzapine group, and 36.2 percent in the placebo group. The most commonly reported adverse events (greater than or equal to 5 percent and twice the rate of placebo) with asenapine included sedation, dizziness, somnolence, oral hypoesthesia, and weight increase.