A comparative study of paliperidone palmitate and risperidone long-acting injectable therapy in schizophrenia

This open-label, rater-blinded, parallel-group study was designed to evaluate noninferiority of paliperidone palmitate (PP), a once-monthly injectable atypical antipsychotic, to once-biweekly risperidone long-acting injectable (RIS-LAI) in adult Chinese patients with acute schizophrenia. Eligible Chinese adults (N=452) with schizophrenia were randomized (1:1) to either PP (N=229; deltoid injections on day 1 [150 mg eq.] and day 8 [100 mg eq.]; then once-monthly deltoid or gluteal injections, flexibly dosed [50, 100, or 150 mg eq.]), or RIS-LAI (N=223; once-biweekly gluteal injections, flexibly dosed [25, 37.5 or 50 mg]). RIS-LAI-treated patients received oral risperidone supplementation (1-6 mg/day) at initiation and with RIS-LAI dose increases. Mean (SD) Positive and Negative Syndrome Scale (PANSS) total score at baseline was 83.2 (12.44). Mean (SD) change from baseline to endpoint in PANSS total scores (primary efficacy measure) was: -23.6 (16.28) for PP group and -26.9 (15.43) for RIS-LAI group. PP was noninferior to RIS-LAI (least squares mean difference [95% CI]: -2.3 [-5.20; 0.63]; predetermined non-inferiority margin: -5.5). Mean (SD) change from baseline to endpoint in Clinical Global Impression-Severity scale score was: -1.5 (1.24; PP group), -1.7 (1.16; RIS-LAI group) and in Personal and Social Performance Scale scores was: 16.8 (14.76; PP group), 18.6 (13.92; RIS-LAI group). The incidence of treatment-emergent adverse events (TEAEs) was similar between the two groups (73% [PP]; 75% [RIS-LAI]). The most common TEAEs were akathisia, tremor, and insomnia. The study demonstrated the noninferiority of PP (50-150 mg eq., flexibly dosed, without oral paliperidone supplementation) to risperidone-LAI (25-50 mg, flexibly dosed, with oral risperidone supplementation) for the treatment of acute schizophrenia in adult Chinese patients. PP injections were generally tolerable, and no new safety signals were detected in this population.