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)

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.

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Key information

Conditions

Major Depressive Disorder (MDD) Anxiety Disorders Behavior Behavioral Symptoms Depression Depressive Disorder Depressive Disorder, Major Major Depressive Disorder With Anxious Distress Mental Disorders Mood Disorders

Age range

18 year–66 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Seaport Investigator Site, Plovdiv, Bulgaria

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

SPT-300

Drug

A prodrug of allopregnanolone, a small molecule drug

Other names: LYT-300, GlyphAllo, Glyph Allopregnanolone

Primary outcomes

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

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.

Sponsors and collaborators

Lead sponsor

Seaport Therapeutics

Industry

Collaborators

Premier Research

Registry information

Official study title

A 6-Week, Multicenter, Open-Label, Monotherapy, Extension Study of SPT-300 in Adults With Major Depressive Disorder, With or Without Anxious Distress

Important dates

Study start: 2025
Primary completion: 2027
Study completion: 2027
First posted: Sep 9, 2025
Registry last updated: Jul 13, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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