A Clinical Study That Will Measure How Well SEP-363856 Works and How Safe it is in Adults With Generalized Anxiety Disorder

A Phase 2/3, Randomized, Double-blind, Parallel Group, Placebo-controlled, Flexible-dose, Multicenter Study to Evaluate the Efficacy and Safety of SEP-363856 in the Treatment of Adults With Generalized Anxiety Disorder

A clinical study that will meaure how well SEP-363856 works and how safe it is in adults with Generalized Anixety Disorder. This study will be accepting both male and female subjects between the ages of 18 years and 65 years old. The study will be held in Approximately 50 global study centers and approximately 15 additional centers for a separate Japan population. Participation in the study can be up to approximately 12 weeks.

Study Overview

• Status: Completed
• Conditions: Generalized Anxiety Disorder
• Intervention / Treatment: Drug: SEP-363856; Drug: Placebo

Detailed Description

This is a multicenter, randomized, double-blind, parallel-group, flexible dose, outpatient study evaluating the efficacy and safety of SEP-363856 flexibly dosed (50 - 75 mg/day) versus placebo over an 8-week Treatment Period in subjects with GAD. This study is projected to randomize approximately 434 subjects to 2 treatment groups (SEP-363856 [50 - 75 mg/day] or placebo) in a 1:1 ratio.

Approximately 30 additional subjects (N = 15 per treatment group) are projected to enroll in the Japan Cohort. Treatment assignment will be stratified by country. Study drug will be taken at approximately the same time each evening at bedtime .

• Study Type: Interventional
• Enrollment (Actual): 434
• Phase: Phase 2; Phase 3

Contacts and Locations

Study Locations

• Bulgaria
  • Pleven, Bulgaria, 5800
    • Medical Center Medconsult Pleven OOD
  • Sofia, Bulgaria, 1510
    • Medical Center Hera EOOD
  • Sofia, Bulgaria, 1408
    • DCC "Sv. Vrach and Sv. Sv. Kuzma and Damyan", OOD
  • Sofia, Bulgaria, 1680
    • Medical Center Intermedica, OOD
  • Sofia, Bulgaria, 1113
    • Medical Center "Sv.Naum"
  • Sofia, Bulgaria, 1000
    • MHC - Sofia, EOOD
  • Varna, Bulgaria, 9020
    • DCC "Mladost M" - Varna, OOD Site #156
  • Varna, Bulgaria, 9020
    • DCC "Mladost M" - Varna, OOD Site #157
  • Plovdiv
    • Sofia, Plovdiv, Bulgaria, 4004
      • Medical Center Mentalcare OOD
• Estonia
  • Tallinn, Estonia, 11315
    • Marienthali Kliinik
  • Tartu, Estonia, 50417
    • Tartu University Hospital
• Finland
  • Helsinki, Finland, 00100
    • Mederon Oy
  • Helsinki, Finland, 00100
    • Aava Laakarikeskus - Aava Kamppi
  • Oulu, Finland, 90100
    • Oulu Mentalcare Oy
  • Tampere, Finland, 33210
    • Satakunnan Psykiatripalvelu
  • Northern Savonia
    • Kuopio, Northern Savonia, Finland, 70110
      • Savon Psykiatripalvelu Oy
• Japan
  • Fukuoka
    • Chikugo-shi, Fukuoka, Japan, 833-0041
      • Uematsu Mental Clinic
    • Fukuoka, Fukuoka, Japan, 810-0004
      • Hiro Mental Clinic
    • Fukuoka, Fukuoka, Japan, 810-0022
      • Shinseikai Kaku Mental Clinic
    • Fukuoka, Fukuoka, Japan, 810-0023
      • Mental Clinic Sakurazaka
    • Kitakyushu-shi, Fukuoka, Japan, 802-0006
      • Kokura Mental Clinic
    • Kurume-shi, Fukuoka, Japan, 830-0033
      • Hirota Clinic
  • Hiroshima
    • Kure-shi, Hiroshima, Japan, 737-0111
      • Hayakawa Clinic
  • Hokkaido
    • Sapporo, Hokkaido, Japan, 003-0003
      • Higashi-Sapporo Mental Clinic
    • Sapporo, Hokkaido, Japan, 062-0922
      • Shimode Mental Clinic
  • Okinawa
    • Naha, Okinawa, Japan, 900-0004
      • Akari Clinic
    • Urasoe-shi, Okinawa, Japan, 901-2104
      • Barclay Imuro Mental Clinic
  • Tokyo-To
    • Meguro-ku, Tokyo-To, Japan, 152-0012
      • Senzoku Psychosomatic Medicine Clinic
    • Setagaya-ku, Tokyo-To, Japan, 154-0004
      • Sangenjaya Nakamura Mental Clinic
    • Setagaya-ku, Tokyo-To, Japan, 154-0004
      • Sangenjaya Neurology- Psychosomatic Clinic
• Slovakia
  • Bratislava, Slovakia, 82007
    • MENTUM, s.r.o.
  • Košice, Slovakia, 040 01
    • Epamed sro
  • Rimavská Sobota, Slovakia, 97901
    • PsychoLine s.r.o.
  • Vranov nad Topľou, Slovakia, 9301
    • Crystal Comfort s.r.o.
  • Zlaté Moravce, Slovakia, 95301
    • BONA MEDIC, s.r.o.
• Spain
  • Barcelona, Spain, 8025
    • Hospital De La Santa Creu I Sant Pau
  • Barcelona, Spain, 8025
    • Institucion Hospitalaria Hestia Palau
  • Madrid, Spain, 28031
    • Hospital Universitario Infanta Leonor
  • Málaga, Spain, 29200
    • Hospital de Antequera
  • Madrid
    • Alcorcón, Madrid, Spain, 28922
      • Hospital Universitario Fundación Alcorcón
  • Principality of Asturias
    • Langreo, Principality of Asturias, Spain, 33920
      • Hospital Valle del Nalon
• Sweden
  • Gothenburg, Sweden, 416 50
    • Sahlgrenska Universitetssjukhuset - Östra sjukhuset
  • Lund, Sweden, 22222
    • ProbarE- Lund
  • Malmo, Sweden, 21152
    • PharmaSite AB Malmö
  • Stockholm, Sweden, 113 29
    • ProbarE- Stockholm
• United States
  • Alabama
    • Huntsville, Alabama, United States, 35801
      • University of Alabama at Birmingham
  • Arizona
    • Phoenix, Arizona, United States, 85012
      • IMA Clinical Research Phoenix
  • California
    • Culver City, California, United States, 90230
      • ProScience Research Group
    • Oceanside, California, United States, 92056
      • Excell Research, Inc.
    • Redlands, California, United States, 92374
      • Anderson Clinical Research
    • Sherman, California, United States, 91403
      • California Neuroscience Research, LLC
    • Sherman Oaks, California, United States, 91403
      • Schuster Medical Research Institute
    • Temecula, California, United States, 92591
      • Viking Pharmaceutical Trials Inc. dba Viking Clinical Research
    • Torrance, California, United States, 90502
      • CenExel Collaborative Neuroscience Research
    • Upland, California, United States, 91786
      • Pacific Clinical Research Management Group
  • Florida
    • Jacksonville, Florida, United States, 32256
      • CNS Healthcare
    • Orlando, Florida, United States, 32803
      • Combined Research Orlando
    • Tampa, Florida, United States, 33607
      • K2 Medical Research, LLC
  • Georgia
    • Atlanta, Georgia, United States, 30328
      • NeuroTrials Research, Inc.
    • Atlanta, Georgia, United States, 30318
      • Advanced Discovery Research LLC
    • Atlanta, Georgia, United States, 30030
      • CenExel iResearch Atlanta
    • Savannah, Georgia, United States, 31405
      • CenExel iResearch Savannah
  • Illinois
    • Chicago, Illinois, United States, 60640
      • Uptown Research Institute, LLC
    • Warrenville, Illinois, United States, 60555
      • American Medical Research, Inc.
  • Massachusetts
    • Boston, Massachusetts, United States, 02131
      • Boston Clinical Trials
    • Boston, Massachusetts, United States, 02116
      • Copley Clinical
    • Watertown, Massachusetts, United States, 02472
      • Adams Clinical
  • Missouri
    • Saint Charles, Missouri, United States, 63304
      • Midwest Research Group
  • New Jersey
    • Cherry Hill, New Jersey, United States, 08002
      • Center for Emotional Fitness Site
    • Marlton, New Jersey, United States, 08053
      • CenExel Hassman Research Institute
  • New York
    • Brooklyn, New York, United States, 11235
      • Social Psychiatry Research Institute
    • Cedarhurst, New York, United States, 11516
      • Neurobehavioral Research, Inc.
    • Mount Kisco, New York, United States, 10016
      • Bioscience Research, LLC
    • New York, New York, United States, 10036
      • Manhattan Behavioral Medicine
    • New York, New York, United States, 10029
      • Berman Clinical
    • New York, New York, United States, 10128
      • The Medical Research Network, L.L.C
  • Ohio
    • North Canton, Ohio, United States, 44720
      • Neuro-Behavioral Clinical Research, Inc.
  • Oklahoma
    • Oklahoma City, Oklahoma, United States, 73112
      • Sooner Clinical Research
    • Oklahoma City, Oklahoma, United States, 73116
      • Paradigm Research Professionals, LLP
  • Pennsylvania
    • Allentown, Pennsylvania, United States, 18104
      • Lehigh Center for Clinical Research, LLC
  • Texas
    • Austin, Texas, United States, 78737
      • Psychiatry and Psychotherapy Partners Austin
    • Dallas, Texas, United States, 75231
      • FutureSearch Trials of Dallas, LP
  • Utah
    • Draper, Utah, United States, 84020
      • Cedar Clinical Research, Inc.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria: (list is not all inclusive)

• Male or female subject between 18 to 65 years of age.
• Subject meets DSM-5 criteria for a diagnosis of Generalized Anxiety Disorder.
• Subject must be willing and able to comply with the study procedures and visit schedule and must be able to understand and follow verbal and written instructions.

Exclusion Criteria: (list is not all inclusive)

• Subject has DSM-5-based diagnosis of any disorder other than Generalized Anxiety Disorder that was the primary focus of treatment within 12 months before Screening.
• Subjects who report an inadequate response to more than 3 antidepressant treatments
• Subject is at significant risk of harming self or others based on Investigator's judgment.
• 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.
• Female subject who is pregnant, lactating, or plans to get pregnant during the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: SEP-363856; dosed once daily tablet	Drug: SEP-363856; once daily tablet
Placebo Comparator: Placebo; dosed once daily tablet	Drug: Placebo; once daily tablet

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from Baseline in Hamilton Anxiety Rating Scale (HAM-A) total score at Endpoint	The HAM-A scale consists of 14 items, each defined by a series of symptoms. Each item is rated on a 5-point (0-4) scale, with higher scores indicating greater severity.	Week 8

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from Baseline in Clinical Global Impression-Severity (CGI-S) score at Endpoint	The CGI-S is a clinician-rated assessment of the subject's current illness state on a 7-point scale, where a higher score is associated with greater illness severity.	Week 8

Collaborators and Investigators

• Sponsor: Otsuka Pharmaceutical Development & Commercialization, Inc.
• Investigators: Study Chair: CNS Medical Director, Sumitomo Pharma America, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): March 8, 2023
• Primary Completion (Actual): September 26, 2025
• Study Completion (Actual): September 26, 2025

Study Registration Dates

• First Submitted: February 6, 2023
• First Submitted That Met QC Criteria: February 6, 2023
• First Posted (Actual): February 15, 2023

Study Record Updates

• Last Update Posted (Estimated): October 10, 2025
• Last Update Submitted That Met QC Criteria: October 8, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: Generalized Anxiety Disorder
• Additional Relevant MeSH Terms: Mental Disorders; Anxiety Disorders; Generalized Anxiety Disorder; Substandard Drugs; Pharmaceutical Preparations; SEP-363856
• Other Study ID Numbers: SEP361-226; 2022-502077-42-00 (Other Identifier: EMA); jRCT2031230152 (Registry Identifier: Japan Registry for Clinical Trials (jRCT))

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 which can be found here: https://vivli.org/ourmember/Otsuka/
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

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