Long-term use of extended-release paliperidone helps patients control symptoms of schizophrenia and maintain improvements in personal and social function, according to a presentation at the annual International Congress on Schizophrenia Research.

"Schizophrenia imposes serious, lifelong psychological, physical, social, and economic burdens on patients, caregivers and heath care systems worldwide," said Herb Meltzer, MD, Bixler/May/Johnson Professor of Psychiatry & Pharmacology at Vanderbilt University School of Medicine. "I am encouraged by the results of this pooled analysis because of the need for antipsychotic treatment options that provide effective symptom control, good tolerability, and which help to sustain the ability of patients to function over the long term."

In a pre-planned analysis, researchers evaluated data from 1,083 patients at 168 centers across North America, Europe, Asia, South Africa, and 12 other countries in the open-label extension of three similarly designed six-week double-blind studies. In the 52-week pen-label extension phase, patients maintained effective symptom control and improvement in personal and social performance achieved during the six-week double-blind phase.

The three previously completed six-week, placebo-controlled trials demonstrated efficacy and tolerability for paliperidone in treatment of schizophrenia. In this study, participants were treated with flexible doses (3mg to 15mg once daily, with 9 mg as the starting dose) after concluding previous double-blind study treatment. The study population was segmented into three subgroups based on treatment experience during the initial six-week trials: placebo to paliperidone; paliperidone to paliperidone; and olanzapine to paliperidone.

Because there were more active treatment (paliperidone) groups in the short-term efficacy trials, most patients entering the extension study had previously received short-term treatment with paliperidone. Patient groups receiving paliperidone in the short-term efficacy trials were shown to have significantly improved by the end of short-term treatment when they became eligible to enter the extension phase, both in symptoms and in functioning compared with placebo.

In total, 47 percent of patients completed the longer-term 52-week study.

Efficacy analyses included change from baseline to end point in Positive and Negative Syndrome Scale (PANSS) total score and the Personal and Social Performance (PSP) scale, a measure of personal and social functioning.

Improvements in PANSS total score in all treatment groups were observed over the first 12 weeks of the extension study and were maintained throughout the remainder of the 52-week trial. Mean PANSS total scores improved from open-label baseline most notably in patients in the placebo-to-paliperidone group. Improvements seen in patient personal and social functioning during the six-week placebo-controlled trial, were maintained over the 52-week period.

"The pooled efficacy data suggest to me that long-term treatment with INVEGA (paliperidone) helps to sustain symptom control and social functioning," concluded Meltzer.

The safety profile was generally consistent with the 6-week data. The most common treatment-emergent adverse events that occurred at a rate of 10 percent or more were extrapyramidal disorder (25 percent), insomnia (14 percent), headache (12 percent), and akathisia (11 percent). Events occurred in a total of 76 percent of participants, although only 7 percent of patients in the trial withdrew from the study due to adverse effects. Total mean change in bodyweight during the 52-week extension trial was an average of 1.1 kg.