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Evaluating the effectiveness and safety of SEP-363856 for treating Generalized Anxiety Disorder in adults

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

Phase2; Phase3 Interventional Otsuka Pharmaceutical Development & Commercialization, Inc. · NCT05729373

This study is testing a new medication called SEP-363856 to see if it can help adults with Generalized Anxiety Disorder feel better over an 8-week period.

Quick facts

PhasePhase2; Phase3
Study typeInterventional
Enrollment434 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorOtsuka Pharmaceutical Development & Commercialization, Inc. Industry-sponsored
Locations84 sites (Huntsville, Alabama and 83 other locations)
Trial IDNCT05729373 on ClinicalTrials.gov

What this trial studies

This clinical study is designed to assess the efficacy and safety of SEP-363856 in adults diagnosed with Generalized Anxiety Disorder (GAD). It will involve a multicenter, randomized, double-blind, parallel-group approach, with participants receiving either SEP-363856 or a placebo over an 8-week treatment period. Approximately 434 subjects will be randomized in a 1:1 ratio, with an additional cohort in Japan. Participants will take the study drug at bedtime, and the study will last up to 12 weeks.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 to 65 who meet the DSM-5 criteria for Generalized Anxiety Disorder.

Not a fit: Patients with other primary psychiatric disorders or those who have not responded to multiple antidepressant treatments may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a new treatment option for patients suffering from Generalized Anxiety Disorder.

How similar studies have performed: Other studies have shown promise in treating anxiety disorders with novel pharmacological approaches, but this specific treatment is being evaluated for the first time.

Eligibility criteria

Show full inclusion / exclusion criteria 
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.

Where this trial is running

Huntsville, Alabama and 83 other locations

+34 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Generalized Anxiety Disorder
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.