Schering-Plough’s investigational drug SAPHRIS (asenapine) 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. In the study, these symptoms were assessed using the validated 16-item Negative Symptom Assessment scale (NSA-16).
This study was a 26-week extension of a randomized, double-blind, multicentered, multinational clinical trial. It evaluated the efficacy and safety of SAPHRIS compared to olanzapine, in the treatment of patients with stable predominant, persistent negative symptoms of schizophrenia.
Reportedly, the patients were initially randomized in the core study to SAPHRIS 5 to 10mg twice daily or olanzapine 5 to 20mg once daily for 26 weeks. In the core study, both SAPHRIS 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, SAPHRIS demonstrated 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, SAPHRIS was more effective than olanzapine 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.
Armin Szegedi, vice president, Global Clinical Research at Schering-Plough Research Institute, said: These symptoms are among the most difficult to treat in the schizophrenia spectrum. Few studies with the antipsychotics currently available on the market have been designed specifically to evaluate long-term effects on predominant, persistent negative symptoms. The results from this large clinical study program will provide new insights into potential treatment of these symptoms.