Efficacy, Safety, and Tolerability of RBP-7000 Once-Monthly Risperidone for the Treatment of Acute Schizophrenia

RBP-7000 is a sustained-release formulation of risperidone for the treatment of schizophrenia, designed to be administered by once-monthly subcutaneous injection using the ATRIGEL delivery system. This study assessed the efficacy, safety, and tolerability of RBP-7000 compared with placebo in subjects with acute exacerbation of schizophrenia. Inpatients were randomly assigned to 8 weeks of double-blind treatment with subcutaneous 90 or 120 mg of RBP-7000 or placebo. Efficacy was evaluated using a mixed-model repeated-measures analysis of the change from baseline (the last nonmissing value before the first dose of RBP-7000 or placebo on day 1) to end of the study in Positive and Negative Syndrome Scale (PANSS) total score (primary efficacy measure) and Clinical Global Impression-Severity score (secondary efficacy measure). The least-squares means from the repeated-measures analysis for the change from baseline in the PANSS total scores for placebo was -9.219 (SE, 1.2162). RBP-7000 produced statistically and clinically significant differences in mean reductions from baseline in PANSS total scores (90-mg RBP-7000 compared with placebo, -6.148 [-9.982 to -2.314], P = 0.0004; 120-mg RBP-7000 compared with placebo, -7.237 [-11.045 to -3.429], P < 0.0001) and significantly improved Clinical Global Impression-Severity scores (90-mg RBP-7000 compared with placebo, -0.350 [-0.557 to -0.143], P = 0.0002; 120-mg RBP-7000 compared with placebo, -0.396 [-0.602 to -0.190], P < 0.0001). Both RBP-7000 dosages were generally well tolerated. The most frequently reported treatment-emergent adverse events in RBP-7000 groups compared with placebo were somnolence, weight gain, and akathisia. The overall incidence of extrapyramidal syndrome-related effects was low and similar across groups. RBP-7000 may provide a new, long-acting alternative treatment for use in adults with acute schizophrenia.