A Study to Detect the Radioactivity of 14C-SEP-380135 in Urine and Feces in Healthy Male Adults

A Phase 1 Trial to Assess the Mass Balance and Pharmacokinetics of a Single Oral Administration of 14C-SEP-380135 in Healthy Male Adults

The purpose of the present trial is to obtain information on the absorption, distribution, metabolism, excretion and pharmacokinetics (PK) of 14C-SEP-380135 and its metabolites following a single oral dose.

Study Overview

• Status: Not yet recruiting
• Conditions: Schizophrenia
• Intervention / Treatment: Drug: 14C-SEP-380135

• Study Type: Interventional
• Enrollment (Estimated): 8
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Otsuka Call Center; Phone Number: 844-687-8522; Email: Otsuka-ProfessionalServices@otsuka-us.com

Study Locations

• United States
  • Nebraska
    • Lincoln, Nebraska, United States, 68502
      • Celerion, Inc.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Body mass index (BMI) between 18.0 and 32.0 kilograms per square meter (kg/m²).

2. In good overall health, based on:

   1. Medical history
   2. Physical examination
   3. Neurological examination
   4. Vital signs
   5. Electrocardiogram (ECG)
   6. Blood and urine tests (serum chemistry, hematology, urinalysis, serology)
3. Regular daily bowel movements (at least one per day) for 30 days before Day -2.
4. Ability to provide written informed consent and follow all study instructions.
5. Has a stable living situation at screening and agrees to return to a similar living arrangement after the in-clinic stay.

Exclusion Criteria:

1. Have taken an investigational drug within 30 days or 5 half-lives, if known, (whichever is longer) prior to screening.
2. Have had prior exposure to SEP-380135.
3. Are currently participating in another clinical trial.
4. Attempted suicide within 12 months prior to screening.
5. A history of sick sinus syndrome, any degree of atrioventricular block, Heart attack (myocardial infarction), heart failure (NYHA Class II-IV), cardiomyopathy, pulmonary congestion, cardiac arrhythmias, prolonged QT interval, congenital long QT syndrome, family history of long QT, or moderate to severe hypokalemia. A participant with non-clinically significant ECG abnormalities at screening and check-in requires approval from the medical monitor and the sponsor's physician.
6. Are predicted poor metabolizer CYP2D6 phenotypes. Note: Other protocol-specified inclusion/exclusion criteria may apply.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 14C-SEP-380135; Participants receive a single oral administration of 14C-SEP-380135 on Day 1.	Drug: 14C-SEP-380135; Oral Capsule

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Total Radioactivity Amount Excreted in Urine (Ae,u)	Up to Day 8
Total Radioactivity Amount Excreted in Feces (Ae,f)	Up to Day 8
Fraction of Dose Excreted in Urine (%fe,u)	Up to Day 8
Fraction of Dose Excreted in Feces (%fe,f)	Up to Day 8

Secondary Outcome Measures

Outcome Measure	Time Frame
Maximum Plasma Concentration (Cmax) of SEP-380135 and Metabolites	Up to Day 8
Time for Cmax (tmax) of SEP-380135 and Metabolites	Up to Day 8
Area Under the Concentration-Time Curve From Time Zero to the Last Observable Concentration at Time (AUCt) of SEP-380135 and Metabolites	Up to Day 8
Area Under the Concentration-Time Curve From Time Zero to Infinity (AUC∞) of SEP-380135 and Metabolites	Up to Day 8
Elimination Half-Life (t1/2,z) of SEP-380135 and Metabolites	Up to Day 8
Apparent Clearance of Drug From Plasma After Oral Administration (CL/F) of SEP-380135	Up to Day 8
Apparent Clearance of Drug From Plasma After Oral Administration Adjusted for Body Weight (CL/F/BW) of SEP-380135	Up to Day 8
Volume of Distribution Following Oral Administration (Vz/F) of SEP-380135	Up to Day 8
Number of Participants with Adverse Events (AEs)	Up to Day 31
Number of Participants with Potentially Clinically Significant Changes in Vital Signs	Upto Day 8
Number of Participants With Potentially Clinically Significant Changes in Electrocardiogram (ECG) Parameters	Upto Day 8
Number of Participants With Potentially Clinically Significant Changes in Physical Examinations	Upto Day 8
Number of Participants With Potentially Clinically Significant Changes in Clinical Laboratory Test Parameters	Upto Day 8
Number of Participants With Incidence of Suicidal Ideation and Suicidal Behavior Using the Columbia-Suicide Severity Rating Scale (C-SSRS)	Upto Day 8

Collaborators and Investigators

• Sponsor: Otsuka Pharmaceutical Development & Commercialization, Inc.

Publications and helpful links

Helpful Links

• Otsuka Clinical Trials website

Study record dates

Study Major Dates

• Study Start (Estimated): March 20, 2026
• Primary Completion (Estimated): April 10, 2026
• Study Completion (Estimated): May 3, 2026

Study Registration Dates

• First Submitted: March 3, 2026
• First Submitted That Met QC Criteria: March 3, 2026
• First Posted (Actual): March 6, 2026

Study Record Updates

• Last Update Posted (Actual): March 6, 2026
• Last Update Submitted That Met QC Criteria: March 3, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Mental Health Conditions, Schizophrenia
• Additional Relevant MeSH Terms: Schizophrenia Spectrum and Other Psychotic Disorders; Mental Disorders; Schizophrenia
• Other Study ID Numbers: 384-201-00003

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• 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.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No