Asenapine ( Saphris ) met the primary endpoint over one year of treatment in an extension study in patients with predominant, persistent negative symptoms of schizophrenia.
Negative symptoms of schizophrenia include apathy, lack of emotion and poor social functioning, among others. In the study, these symptoms were assessed using the validated 16-item Negative Symptom Assessment scale ( NSA-16 ).
In the study, Asenapine was significantly more effective than Olanzapine ( Zyprexa ) in the reduction of negative symptoms as measured by change from baseline to day 365 in the NSA-16 total score, the primary endpoint of the study. By using a mixed model for repeated measures ( MMRM ), least square mean changes in the NSA-16 total score were -15.8 for Asenapine versus -11.0 for Olanzapine ( P=0.015 ).
The study was a 26-week extension of a randomized, double-blind, multicentered, multinational 26-week clinical trial evaluating the efficacy and safety of Asenapine compared to Olanzapine in the treatment of patients with stable predominant, persistent negative symptoms of schizophrenia.
Patients were initially randomized in the core study to Asenapine 5 to 10 mg twice daily or Olanzapine 5 to 20 mg once daily for 26 weeks.
In the core study, both Asenapine and Olanzapine reduced negative symptoms over the 26-week treatment period, but the difference between the two was not statistically significant. Patients who continued after six months were maintained on the same double-blind treatment regimen for the 26-week extension study.
In the extension study, Asenapine demonstrated statistically significantly greater change in NSA-16 total score from the core study baseline after one year of treatment, the primary prespecified endpoint of the extension study. A total of 468 patients were randomized in the core study, 195 of whom entered the extension study, with 146 completing a total of one year of treatment.
In the study, the most common adverse events reported for the Asenapine group ( greater than 5% ) during the one year treatment period were: insomnia, somnolence, weight increase, anxiety, headache, weight decrease, akathisia, diarrhea, dizziness, fatigue, nasopharyngitis, blood insulin increase, irritability, dry mouth and nausea.
Schizophrenia is a chronic, disabling brain disorder characterized by hallucinations, delusions and disordered thinking ( often termed positive symptoms ), and cognitive deficits, as well as negative symptoms such as apathy, avolition, diminished social drive, poverty of speech or curbing of interest, which are frequent disabling symptoms. About 24 million people worldwide ( or seven in every 1,000 adults in the population ) have schizophrenia, including more than two million people in the United States and more than four million people in Europe.
Source: Schering-Plough, 2009