Safety and efficacy of paliperidone extendedrelease in Chinese patients with schizophrenia: a 24-week, open-label extension of a randomized, double-blind, placebo-controlled study

Objectives: The long-term safety, tolerability, and efficacy of paliperidone extended-release (ER) were evaluated in Chinese patients with schizophrenia. Methods: Patients (aged. 18 years) with schizophrenia (Diagnostic and Statistical Manual of Mental Disorders, 4th edition criteria) who had completed run-in (8-week), stabilization (6-week), and double-blind (DB) phases (variable) of a phase-3, placebo-controlled study entered this 24-week, open-label extension (OLE) study. These patients, who had either experienced a relapse or remained relapse-free through DB phase of the study, were treated with flexible-dose paliperidone-ER (3-12 mg/day) during the OLE phase. Major safety evaluations included treatment-emergent adverse events (TEAEs) and extrapyramidal symptoms. Efficacy endpoints included changes in Positive and Negative Syndrome Scale total score, Clinical Global Impression-Severity scale, and Personal and Social Performance scale from OLE baseline to OLE endpoint. Results: Out of 106 patients who entered the OLE phase (placebo: 59, paliperidone-ER: 47), a total of 85 (80%) completed it. Thirty-five (33%) patients experienced at least one TEAE; most common were akathisia, somnolence, nasopharyngitis, and constipation (3.8% each). Serious TEAEs were noted in two patients (completed suicide; schizophrenia worsening). No TEAEs with an onset during the OLE phase led to discontinuation. Extrapyramidal symptoms related-TEAEs were reported in eight (7.5%) patients. Mean (standard deviation) changes in Positive and Negative Syndrome Scale total scores (-10.4[13.2]), Clinical Global Impression-Severity scores (-0.6[0.96]) and Personal and Social Performance scores (7.4[13.2]) from OLE baseline to OLE endpoint showed patients who had been treated with placebo during the DB phase experienced more pronounced improvements. Conclusion: In this OLE study, flexibly dosed paliperidone-ER (3-12 mg/day) was tolerable and efficacious in Chinese patients with schizophrenia.