A Clinical Trial to Study the Efficacy and Safety of an Investigational Drug in Acutely Psychotic People With Schizophrenia

This is a multicenter, randomized, double-blind, parallel-group, fixed-dosed study evaluating the efficacy and safety of two doses of SEP-363856 (50 and 75 mg/day) versus placebo over a 6-week Treatment Period in acutely psychotic subjects with schizophrenia. This study is projected to randomize approximately 435 subjects (18-65 years) to 3 treatment groups (SEP-363856 50 mg/day, SEP-363856 75 mg/day, or placebo) in a 1:1:1 ratio. In addition, the study will randomize approximately 90 adolescent subjects (13-17 years) in a 1:1:1 ratio to the 3 treatment groups (with approximately 30 subjects per group) in a separate cohort. Treatment assignment will be stratified by country. Study drug will be taken once a day and may be taken with or without food.

This study is designed to test the hypothesis that, treatment with SEP-363856 in adult subjects with schizophrenia will result in significantly greater reduction (i.e. improvement) in PANSS total score and CGI-S score at Week 6 from Baseline when compared to placebo. The overall Type I error is controlled for two hierarchical families of hypotheses. The first family includes hypotheses about the testing of change from Baseline in PANSS total score at Week 6 between each of the SEP-363856 dose levels vs. placebo. The second family of hypotheses are about the testing of change from Baseline in CGI-S score at Week 6 between each of the SEP-363856 dose levels vs. placebo.

Sumitomo Pharma America Inc. was the former Sponsor and conducted this study. Sumitomo was responsible for analysis and clinical study report (CSR) completion. Otsuka took over study after IND was transferred and is concluding activities with registry postings.

Primary Outcome Measures

1. Change From Baseline in PANSS Total Score at Week 6
   PANSS was an interview-based assessment comprised of 30 items and 3 subscales (Positive, Negative, General Psychopathology). The Positive subscale assessed hallucinations, delusions, and related symptoms; the Negative subscale assessed emotional withdrawal, lack of motivation, and similar symptoms; and the General Psychopathology subscale addressed other symptoms such as anxiety, somatic concern, and disorientation. An anchored Likert scale from 1 - 7, where values of 2 and above indicated the presence of progressively more severe symptoms, was used to score each item. Individual items were then summed to determine scores for the 3 subscales, as well as a total score. PANSS total score ranges from: 30-210, where a higher score indicates greater severity. A negative change from baseline indicates improvement.

Secondary Outcome Measures

1. Change From Baseline in CGI-S Total Score at Week 6
   The CGI-S was a single-item clinician-rated assessment of the participant's current illness state on a 7-point scale (score range: 1-7), where a higher score was associated with greater illness severity.