Safety and efficacy of paliperidone palmitate 1-month formulation in Chinese patients with schizophrenia: a 25-week, open-label, multicenter, Phase IV study

Rationale Long-acting injectable (LAI) paliperidone palmitate 1-month formulation (PP1M) has demonstrated acceptable tolerability and favorable clinical outcomes in Western and Asian patients with schizophrenia. Hence, analysis of the outcomes of long-term PP1M treatment specifically in Chinese patients is of interest. Objective The aim of this study is to evaluate the long-term safety and efficacy of PP1M treatment in Chinese patients with schizophrenia. Methods In this 25-week, open-label, Phase IV study, patients (18–65 years) diagnosed with schizophrenia and having a baseline Positive and Negative Syndrome Scale (PANSS) total score of 60–120 (inclusive) were enrolled. All patients received injections of PP1M 150 mg eq. (day 1) and 100 mg eq. (day 8), followed by a flexible once-monthly maintenance dosing (75, 100, or 150 mg eq.). Results Of the 353 patients, 234 (66.3%) completed the study treatment (mean age, 31.1 years; 52.7% men). The PANSS total score (primary end point) improved significantly over the 6-month treatment period (mean [standard deviation] change from baseline to end of treatment, −27.2 [18.30]; P<0.0001). The Clinical Global Impressions-Severity and Personal and Social Performance scores (secondary end points) also improved significantly (P<0.0001). At 6 months, PP1M had a positive impact on medication satisfaction, adherence, and increased preference for LAIs. Treatment-emergent adverse events (TEAEs) were reported by 181 (51.3%) patients (TEAEs ≥5%: extrapyramidal disorder [15.3%], akathisia [10.5%], blood prolactin increase [8.8%], insomnia [5.4%]). A total of 8 deaths were reported, including 4 completed suicides. Conclusion Long-term treatment with PP1M was efficacious, and no new safety concerns were identified in Chinese patients with schizophrenia. Overall, the results were comparable with observations from previous studies.