An Open-Label Extension Study to Evaluate the Safety and Tolerability of SPT-300 (GlyphAllo) in Participants With Major Depressive Disorder, With or Without Anxious Distress (BUOY-1 OLE Study)
October 2, 2026 updated by: Seaport Therapeutics
A 6-Week, Multicenter, Open-Label, Monotherapy, Extension Study of SPT-300 in Adults With Major Depressive Disorder, With or Without Anxious Distress
This is an open-label, monotherapy, extension study to evaluate the safety and tolerability of SPT-300 (GlyphAllo) in adults with major depressive disorder (MDD), with or without anxious distress.
Study Overview
Status
Enrolling by invitation
Intervention / Treatment
Study Type
Interventional
Enrollment (Estimated)
360
Phase
- Phase 2
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
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Plovdiv, Bulgaria, 4004
- Seaport Investigator Site
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Sofia, Bulgaria, 1000
- Seaport Investigator Site
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Brno, Czechia, 602 00
- Seaport Investigator Site
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Prague, Czechia, 100 00
- Seaport Investigator Site
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Prague, Czechia, 186 00
- Seaport Investigator Site
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Prague, Czechia, 110 00
- Seaport Investigator Site
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Prague, Czechia, 160 00
- Seaport Investigator Site
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Bad Homburg, Germany, 61348
- Seaport Investigator Site
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Chemnitz, Germany, 09111
- Seaport Investigator Site
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Brandenburg
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Berlin, Brandenburg, Germany, D-10629
- Seaport Investigator Site
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Mecklenburg-Vorpommern
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Schwerin, Mecklenburg-Vorpommern, Germany, 19053
- Seaport Investigator Site
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Budapest, Hungary, 1033
- Seaport Investigator Site
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Budapest, Hungary, 1134
- Seaport Investigator Site
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Bialystok, Poland, 15-404
- Seaport Investigator Site
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Bialystok, Poland, 15-464
- Seaport Investigator Site
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Bydgoszcz, Poland, 85-080
- Seaport Investigator Site
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Gdansk, Poland, 80-438
- Seaport Investigator Site
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Leszno, Poland, 64-100
- Seaport Investigator Site
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Poznan, Poland, 60-744
- Seaport Investigator Site
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Tuszyn, Poland, 95-080
- Seaport Investigator Site
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Rimavská Sobota, Slovakia, 979 01
- Seaport Investigator Site
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Vranov nad Topľou, Slovakia, 09301
- Seaport Investigator Site
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California
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Chino, California, United States, 91710
- Seaport Investigator Site
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Garden Grove, California, United States, 92845-2506
- Seaport Investigator Site
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Glendale, California, United States, 91206
- Seaport Investigator Site
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San Jose, California, United States, 95124
- Seaport Investigator Site
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Connecticut
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Cromwell, Connecticut, United States, 06416
- Seaport Investigator Site
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Florida
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Lauderhill, Florida, United States, 33319
- Seaport Investigator Site
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Palm Bay, Florida, United States, 32905
- Seaport Investigator Site
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West Palm Beach, Florida, United States, 33407
- Seaport Investigator Site
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Georgia
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Atlanta, Georgia, United States, 30328
- Seaport Investigator Site
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Decatur, Georgia, United States, 30030
- Seaport Investigator Site
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Massachusetts
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Boston, Massachusetts, United States, 02116
- Seaport Investigator Site
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Missouri
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St Louis, Missouri, United States, 63141
- Seaport Investigator Site
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New York
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Brooklyn, New York, United States, 11235
- Seaport Investigator Site
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Cedarhurst, New York, United States, 11516
- Seaport Investigator Site
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New York, New York, United States, 10029
- Seaport Investigator Site
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Staten Island, New York, United States, 10314
- Seaport Investigator Site
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Ohio
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Independence, Ohio, United States, 44131
- Seaport Investigator Site
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North Canton, Ohio, United States, 44720
- Seaport Investigator Site
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Texas
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Irving, Texas, United States, 75062
- Seaport Investigator Site
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Richardson, Texas, United States, 75080
- Seaport Investigator Site
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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
Ages Eligible for Study
18 years to 66 years (Adult, Older Adult)
Accepts Healthy Volunteers
No
Genders Eligible for Study
All
Description
Inclusion Criteria:
- Participant who completed treatment in Study SPT-300-2024-203 (i.e., participant who competed Visit 8 [Day 42] of Study SPT-300-2024-203 [BUOY-1 Study]).
- Women of childbearing potential (WOCP) must not plan to become pregnant during the course of the study or be currently breastfeeding. WOCP must agree to use a highly effective form of contraception during participation in the study and for 30 days after receiving the last dose of study treatment.
- Participant is willing and able to refrain from the use of drugs of abuse.
Exclusion Criteria:
- Participants who, in the opinion of the Investigator, medical monitor, or Sponsor, should not participate in the study.
- Participants who, in the judgment of the Investigator, were noncompliant with trial procedures or with study treatment administration during the double-blind study (BUOY-1 Study).
- Female participants with a positive urine pregnancy test result. Female participants may be enrolled without a negative urine test if they are surgically sterile or at least 2 years post-menopause.
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: N/A
- Interventional Model: Single Group Assignment
- Masking: None (Open Label)
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
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Experimental: SPT-300
Participants will receive SPT-300 capsules once daily for 42 days |
A prodrug of allopregnanolone, a small molecule drug
Other Names:
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What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
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Safety and tolerability assessments based on Treatment-emergent Adverse Events (TEAEs), Serious Adverse Events (SAEs) and validated clinical scales and procedures
Time Frame: Up to Day 49
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Adverse events (AEs) are monitored from Day 1 to 49. A TEAE is as any AE with an onset after first dose of study treatment up to Day 49. Clinically significant abnormalities in clinical laboratory evaluations, ECGs, vital signs, physical examinations and Columbia Suicide Severity Rating Scale (C-SSRS) will be reported as TEAEs. |
Up to Day 49
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Collaborators and Investigators
This is where you will find people and organizations involved with this study.
Sponsor
Collaborators
Investigators
- Principal Investigator: David Walling, Ph.D., Collaborative Neuroscience Research - Garden Grove
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)
September 2, 2025
Primary Completion (Estimated)
May 1, 2027
Study Completion (Estimated)
May 1, 2027
Study Registration Dates
First Submitted
September 2, 2025
First Submitted That Met QC Criteria
September 2, 2025
First Posted (Actual)
September 9, 2025
Study Record Updates
Last Update Posted (Actual)
October 6, 2026
Last Update Submitted That Met QC Criteria
October 2, 2026
Last Verified
September 1, 2026
More Information
Terms related to this study
Keywords
Additional Relevant MeSH Terms
Other Study ID Numbers
- SPT-300-2024-204
- 2025-522347-18-00 (Ctis)
- 2025 (U.S. NIH Grant/Contract)
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.