A Study of SEP-380135 in Adults With Schizophrenia or Major Depressive Episode

April 17, 2026 updated by: Otsuka Pharmaceutical Development & Commercialization, Inc.

A Phase 1b, Randomized, Double-blind, Placebo-controlled Trial to Assess the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Multiple Ascending Oral Doses of SEP-380135 in Adults With Schizophrenia or With a Major Depressive Episode Associated With Bipolar I or II Disorder or Major Depressive Disorder

The purpose of this study is to assess the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of multiple dose oral administration of SEP-380135 in participants with schizophrenia or with a major depressive episode associated with bipolar I or II disorder or major depressive disorder (MDD).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
43

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Los Alamitos, California, United States, 90720
        • Collaborative Neuroscience Research, LLC

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • BMI from 18.0 to 35.0 kilograms per square meter (kg/m^2) (inclusive).
  • Participants with a primary diagnosis of schizophrenia (cohorts 1 to 3) or bipolar I or II disorder or MDD (cohort 4) for at least 1 year (at screening), as established by clinical review, using the DSM-5 as a reference, and confirmed using the Mini international neuropsychiatric interview (MINI).
  • For cohorts 1 to 3: deemed to have residual symptoms of schizophrenia at screening (i.e., be at least "mildly ill" per CGI-S criteria [CGI-S greater than or equal to (≥) 3]) and a PANSS criteria of less than or equal to (≤) 75. For cohort 4 only: deemed to be currently experiencing an MDE. Participants must be at least "moderately ill" per CGI-S criteria (CGI-S ≥ 4).
  • Ability to provide written, informed consent prior to initiation of any trial-related procedures, and ability, in the opinion of the PI, to comply with all the requirements of the trial.

Exclusion Criteria:

  • Attempted suicide within 12 months prior to screening
  • A disorder or history of a condition, or previous gastrointestinal conditions that may interfere with drug absorption, distribution, metabolism, excretion, gastrointestinal motility, or pH, or a history of clinically significant abnormality of the hepatic (including participants with moderate [Child-Pugh Class B] and severe [Child-Pugh Class C] hepatic impairment) or renal system (a glomerular filtration rate less than (<) 60 milliliters per minute (mL/min)), or a history of malabsorption, bowel resection, bariatric surgery or gastric band/lap band surgery, or is on medications that might interfere with gastric motility.
  • Aspartate aminotransferase (AST), alanine aminotransferase (ALT), or bilirubin ≥ 2 times the upper limit of the reference ranges provided by the safety laboratory at screening, or total bilirubin ≥ 2 times the upper limit of reference (except for participants with Gilbert's syndrome or similar condition).
  • Has any clinically significant unstable medical condition, clinically significant chronic disease, or any psychiatric symptom or diagnosis that in the opinion of the investigator, MM, or sponsor would pose a risk to the participant or the scientific objectives of the trial.

Note: Other protocol-specified Inclusion/Exclusion criteria may apply.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Sequential Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Cohort 1
Participants receive SEP-380135 Dose Level 1, orally once daily (QD) from Day 1 to Day 14.
Drug: SEP-380135
oral capsule.
Experimental: Cohort 2
Participants receive SEP-380135 Dose Level 2 orally once daily (QD) from Day 1 through Day 14.
Drug: SEP-380135
oral capsule.
Experimental: Cohort 3
Participants receive SEP-380135 Dose Level 3 orally once daily (QD) from Day 1 through Day 14.
Drug: SEP-380135
oral capsule.
Experimental: Cohort 4
Participants receive SEP-380135 Dose Level 4 orally once daily (QD) from Day 1 through Day 14.
Drug: SEP-380135
oral capsule.
Placebo Comparator: Placebo
Participants receive SEP-380135 matching-placebo orally orally once daily (QD) from Day 1 to Day 14.
Drug: Placebo
Placebo capsule.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
All Cohorts: Number of Participants With Adverse Events (AEs), Serious Adverse Events (SAEs), and Treatment Emergent Adverse Events (TEAEs) Leading to Trial Discontinuation
Time Frame: Up to Day 44
Up to Day 44
All Cohorts: Percentage of Participants With Suicidal Ideation or Suicidal Behavior Using the Columbia-Suicide Severity Rating Scale (C-SSRS)
Time Frame: Up to Day 18
Up to Day 18
All Cohorts: Percentage of Participants With Withdrawal Symptoms Using the 20-Item Physician Withdrawal Checklist (PWC-20)
Time Frame: Up to Day 44
Up to Day 44
All Cohorts: Percentage of Participants With Change From Baseline in Potentially Clinically Relevant Laboratory Tests
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Percentage of Participants With Change From Baseline in Potentially Clinically Relevant Vital Signs
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Percentage of Participants With Change From Baseline in Potentially Clinically Relevant Orthostatic Effects
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Actual Values of Weight
Time Frame: Up to Day 18
Up to Day 18
All Cohorts: Change From Baseline in Weight
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Actual Values of Body Mass Index (BMI)
Time Frame: Up to Day 18
Up to Day 18
All Cohorts: Change From Baseline in BMI
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Actual Values of Waist Circumference
Time Frame: Up to Day 18
Up to Day 18
All Cohorts: Change From Baseline in Waist Circumference
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Percentage of Participants With Change From Baseline in 12-Lead Electrocardiogram (ECG)
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Actual Values of QT interval corrected using Fridericia's Formula (QTcF)
Time Frame: Up to Day 18
Up to Day 18
All Cohorts: Change From Baseline in QTcF
Time Frame: Baseline, Day 18
Baseline, Day 18
Cohorts 1, 2, and 3: Actual Values of Clinician-Administered Dissociative States Scale (CADSS) Score
Time Frame: Up to Day 18
Up to Day 18
Cohorts 1, 2, and 3: Change From Baseline in CADSS Score
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Actual Values of Drug Effect Questionnaire (DEQ) Scored Using Visual Analog Scale Score
Time Frame: Up to Day 18
Up to Day 18
All Cohorts: Change From Baseline in DEQ Scored Using Visual Analog Scale Score
Time Frame: Baseline, Day 18
Baseline, Day 18
Cohorts 1, 2, and 3: Actual Values of Barnes Akathisia Rating Scale (BARS) Score
Time Frame: Up to Day 18
Up to Day 18
Cohorts 1, 2, and 3: Change From Baseline in BARS Score
Time Frame: Baseline, Day 18
Baseline, Day 18
Cohorts 1, 2, and 3: Actual Values of Abnormal Involuntary Movement Scale (AIMS) Score
Time Frame: Up to Day 18
Up to Day 18
Cohorts 1, 2, and 3: Change From Baseline in AIMS Score
Time Frame: Baseline, Day 18
Baseline, Day 18
Cohorts 1, 2, and 3: Actual Values of Simpson Angus Scale (SAS) Score
Time Frame: Up to Day 18
Up to Day 18
Cohorts 1, 2, and 3: Change From Baseline in SAS Score
Time Frame: Baseline, Day 18
Baseline, Day 18
Cohorts 1, 2, and 3: Actual Values of Positive and Negative Syndrome Scale (PANSS) Score
Time Frame: Up to Day 18
Up to Day 18
Cohorts 1, 2, and 3: Change From Baseline in PANSS Score
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Actual Values of Clinical Global Impressions-Severity Scale (CGI-S) Score
Time Frame: Up to Day 18
Up to Day 18
All Cohorts: Change From Baseline in CGI-S Score
Time Frame: Baseline, Day 18
Baseline, Day 18
Cohorts 1, 2, and 3: Actual Values of Calgary Depression Scale for Schizophrenia (CDSS) Score
Time Frame: Up to Day 18
Up to Day 18
Cohorts 1, 2, and 3: Change From Baseline in CDSS Score
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Percentage of Participants With Change From Baseline in Physical Examinations
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Percentage of Participants With Change From Baseline in Neurological Examinations
Time Frame: Baseline, Day 18
Baseline, Day 18
Cohort 4: Actual Values of Hamilton Anxiety Rating Scale (HAM-A) Score
Time Frame: Up to Day 18
Up to Day 18
Cohort 4: Change From Baseline in HAM-A Score
Time Frame: Baseline, Day 18
Baseline, Day 18
Cohort 4: Actual Values of Montgomery-Asberg Depression Rating Scale (MADRS) Score
Time Frame: Up to Day 18
Up to Day 18
Cohort 4: Change From Baseline in MADRS Score
Time Frame: Baseline, Day 18
Baseline, Day 18
Cohort 4: Actual Values of Young Mania Rating Scale (YMRS) Score
Time Frame: Up to Day 18
Up to Day 18
Cohort 4: Change From Baseline in YMRS Score
Time Frame: Baseline, Day 18
Baseline, Day 18
All Cohorts: Percentage of Participants With Changes in Quantitative Sleep Parameters Measured Using Electroencephalography (EEG)
Time Frame: Up to Day 17
Up to Day 17
All Cohorts: Apparent Clearance (CL/F) of SEP-380135
Time Frame: Day 14
Day 14
All Cohorts: Volume of Distribution (Vz/F) of SEP-380135
Time Frame: Day 14
Day 14
All Cohorts: Maximum Plasma Concentration (Cmax) of SEP-380135
Time Frame: Day 14
Day 14
All Cohorts: Area Under the Drug Concentration-time Curve From Time Zero Predose to 24 hours Postdose (AUC0-24h) of SEP-380135
Time Frame: Day 14
Day 14

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
All Cohorts: Cmax of SEP-380135 and its Metabolites
Time Frame: Days 1 and 14
Days 1 and 14
All Cohorts: Time to Maximum Plasma Concentration (tmax) of SEP-380135 and its Metabolites
Time Frame: Days 1 and 14
Days 1 and 14
All Cohorts: AUC0-24h of SEP-380135 and its Metabolites
Time Frame: Days 1 and 14
Days 1 and 14
All Cohorts: Observed Plasma Concentration at 24 hours Postdose (C24h) of SEP-380135
Time Frame: Days 1 and 14
Days 1 and 14
All Cohorts: Terminal Phase Elimination Half-Life (t1/2,z) of SEP-380135 and its Metabolites
Time Frame: Day 14
Day 14
All Cohorts: Serum Concentration of SEP-380135 at Steady-State
Time Frame: Day 14
Day 14

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Otsuka Pharmaceutical Development & Commercialization, Inc.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 7, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 12, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 12, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 17, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 17, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 24, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 24, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 17, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 384-201-00002

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. Small studies with less than 25 participants are excluded from data sharing.

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 the Vivli data sharing platform: https://vivli.org/ourmember/Otsuka/

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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