A clinical trial to study the efficacy and safety of an investigational drug in acutely psychotic people with schizophrenia. Participants in the study will either receive the drug being studied or a placebo. This study is accepting male and female participants between 13 years old -65 years old who have been diagnosed 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.

Inclusion Criteria:

1. Male or female subject between 13 to 65 years of age (inclusive) at the time of consent.
2. Subject or subjects parent/legal guardian [adolescents] must give written informed consent and privacy authorization prior to participate in the study; adolescents must also provide informed assent..
3. Subject meets DSM-5 criteria for schizophrenia as established by clinical interview at screening
4. Subject must have a CGI-S score ≥ 4
5. Subject must have a PANSS total score ≥ 80 and a PANSS item score ≥ 4 on 2 or more of the following PANSS items: delusions, conceptual disorganization, hallucinations, and unusual thought content
6. Subject has an acute exacerbation of psychotic symptoms (persisting no longer than 2 months prior to providing informed consent).
7. Subject has marked deterioration of functioning in one or more areas.
8. Subject is, in the opinion of the Investigator, generally healthy based on screening medical history, PE, neurological examination, vital signs, ECG, and clinical laboratory values.

Exclusion Criteria:

1. Subject has a DSM-5 diagnosis or presence of symptoms consistent with a DSM-5 diagnosis other than schizophrenia. Exclusionary disorders include but are not limited to alcohol use disorder (within past 12 months), substance (other than nicotine or caffeine) use disorder within past 12 months or lifetime history of significant substance abuse that in the opinion of the Investigator or Sponsor, may have had a significant and potentially permanent impact of the brain or other body systems, major depressive disorder, bipolar I or II disorder, schizoaffective disorder, obsessive compulsive disorder, and posttraumatic stress disorder. Symptoms of mild to moderate mood dysphoria or anxiety are allowed so long as these symptoms are not the primary focus of treatment.
2. Subject is at significant risk of harming self, others, or objects based on Investigator's judgment.
3. Subject has any clinically significant unstable medical condition or any clinically significant chronic disease that in the opinion of the Investigator, would limit the subject's ability to complete and/or participate in the study:
4. Female subject who is pregnant or lactating
5. Subject has any clinically significant abnormal laboratory value(s) at Screening as determined by the investigator.

Anonymized Individual participant data (IPD) that underlie the results of this study will be shared with researchers to achieve aims pre-specified in a methodologically sound research proposal. Small studies with less than 25 participants are excluded from data sharing.

Data will be available after marketing approval in global markets, or beginning 1-3 years following article publication. There is no end date to the availability of the data.

Otsuka will share data on the Vivli data sharing platform which can be found here: https://vivli.org/ourmember/Otsuka/

double-blind