Objective: First-month data of a 13-week acute schizophrenia study were used to compare paliperidone palmitate to oral risperidone during initiation of long-acting injectable risperidone.
Design: Double-blind, randomized study.
Setting: Outpatient or inpatient.
Participants: Adults with established (≥1 year) schizophrenia. Those assigned to risperidone long-acting injectable (n=460) received 25mg on Days 8 and 22 with oral risperidone (l-6mg) supplementation for the first 28 days. The paliperidone palmitate group (n=453) received 150mg eq. on Day 1, l00mg eq. on Day 8, and oral placebo supplementation for the first 28 days.
Measurements: Positive and Negative Syndrome Scale, Personal and Social Performance Scale, Clinical Global Impression-Severity score, and responder rate (percentage of patients with ≥30% reduction in PANSS total score). An analysis of covariance model estimated least-square mean differences between treatment groups. A post-hoc analysis of efficacy data for the period of interest, i.e., at the time points before and after the first 28 days, was conducted.
Results: Positive and Negative Syndrome Scale, Personal and Social Performance Scale, Clinical global Impression-Severity scores showed similar efficacy between the treatment groups during the first weeks of treatment, corresponding to the risperidone long-acting injection initiation period. Mean Positive and Negative Syndrome Scale total score at baseline was 84.7 for paliperidone palmitate and 84.4 for oral risperidone, on Day 22 was 73.6 and 74.1, respectively, and on Day 36 was 71.8 and 72.8, respectively. Overall incidence of adverse events in the first 28 days was generally similar (45% for paliperidone palmitate vs. 35% for oral risperidone), except for injection site pain (4.6% vs. 0.7%). Similar active moiety plasma concentrations were obtained during this period.
Conclusion: During the first month, paliperidone palmitate without oral supplementation has similar efficacy and safety to oral risperidone (during initiation of risperidone long-acting injectable) in acutely exacerbated schizophrenia.
Keywords: Paliperidone palmitate; acute schizophrenia; long-acting injection; risperidone.