Bioequivalence Study of Long-Acting Paliperidone Palmitate in Patients With Schizophrenia

Purpose: This trial was conducted to evaluate the bioequivalence of a test (T) and a reference (R) formulation of once-monthly paliperidone palmitate (PP1M) in patients with schizophrenia. Patients and methods: In this randomized, open-label, parallel-group, steady-state bioequivalence study, patients with stabilized schizophrenia were randomized 1:1 to receive T or R formulation. The regimen was 150 mg deltoid on Day 1, then 100 mg deltoid on Day 8, followed by five subsequent 100 mg gluteal injections every 28 days. The primary objective was to demonstrate steady-state bioequivalence. The primary endpoints were key pharmacokinetic parameters of paliperidone, including steady-state maximum concentration (Cmax,ss) and the area under the concentration-time curve over a dosing interval at steady state (AUCτ,ss). Bioequivalence was shown if the 90% confidence interval (CI) for the ratio of the geometric least squares means of the pharmacokinetic parameters (AUCτ,ss and Cmax,ss) fell within 80%-125%.