A Long-term Administration Trial of SEP-363856 in Patients With Schizophrenia

A Multicenter, Uncontrolled, Open-label Trial to Evaluate the Tolerability, Safety, and Efficacy of Long-term Administration of SEP-363856 in Patients With Schizophrenia

To evaluate the safety of SEP-363856 (75 mg/day or 100 mg/day) administered for 52 weeks in adult participants with schizophrenia

Study Overview

• Status: Recruiting
• Conditions: Schizophrenia
• Intervention / Treatment: Drug: SEP-363856

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Drug Information Center; Phone Number: +81-3-6361-7314

Study Locations

• Japan
  • Fukuoka, Japan
    • Recruiting
    • Jimbo Kokorono Clinic

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Japanese male or female participants 18 years of age or older at the time of informed consent
• Diagnosed with schizophrenia according to the DSM-5®
• Judged by the investigator to be clinically stable for at least 8 weeks prior to screening
• PANSS total score of 80 or less and CGI-S score 4 or less at both screening and baseline
• No changes in antipsychotic medication for at least 6 weeks before screening (excluding minor dose adjustments for tolerability)

Exclusion Criteria:

• History of psychiatric hospitalization within 8 weeks prior to screening
• Treatment-resistant to antipsychotic therapy (ie, within 1 year to screening, despite administration of two or more marketed antipsychotics at appropriate doses for at least 4 weeks [28 consecutive days] in accordance with the package insert, psychiatric symptoms did not improve)
• History of treatment with clozapine
• Unwillingness, before or during the trial period, to comply with the requirements for prior and concomitant medications/therapies as specified in the protocol or use of prohibited medications at screening or baseline as specified in the protocol.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: SEP-363856 75 or 100 mg/day (dose selected per protocol); SEP-363856 will be administered at 50 mg/day from Day 1 to Day 3, and 75 mg/day from Day 4 to Day 7. From Day 8 onward, the dose will, in principle, be 100 mg/day unless there are tolerability concerns; however, in accordance with protocol, the investigator or sub-investigator may select either 75 mg/day or 100 mg/day.	Drug: SEP-363856; Tablet, once daily, for 52 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
・Incidence of treatment-emergent adverse events (TEAEs)	52 weeks

Collaborators and Investigators

• Sponsor: Otsuka Pharmaceutical Co., Ltd.
• Investigators: Study Director: Nobuhito Sanada, Otsuka Pharmaceutical Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Actual): December 22, 2025
• Primary Completion (Estimated): March 1, 2028
• Study Completion (Estimated): March 1, 2028

Study Registration Dates

• First Submitted: November 5, 2025
• First Submitted That Met QC Criteria: November 5, 2025
• First Posted (Estimated): November 7, 2025

Study Record Updates

• Last Update Posted (Actual): January 14, 2026
• Last Update Submitted That Met QC Criteria: January 13, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Schizophrenia Spectrum and Other Psychotic Disorders; Mental Disorders; Schizophrenia; SEP-363856
• Other Study ID Numbers: 382-102-00050

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: 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.
• IPD Sharing Time Frame: 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.
• IPD Sharing Access Criteria: Otsuka will share data on an Otsuka-owned remotely accessible data sharing platform with Python and R analytical software. Research requests should be directed to clinicaltransparency@Otsuka-us.com.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes