Recruiting
Phase 2

SPT-300

Sponsor:

Seaport Therapeutics

Code:

NCT07065240

Conditions

Major Depressive Disorder (MDD)

Major Depressive Disorder With Anxious Distress

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Not accepted

Interventions

SPT-300

Placebo

Study Details

Brief summary:

This is a randomized, parallel-group, double-blind, placebo-controlled, monotherapy study to evaluate the efficacy, safety, and tolerability of SPT-300 (GlyphAllo) in adults with major depressive disorder (MDD), with or without anxious distress.

Conditions

Major Depressive Disorder (MDD)

Major Depressive Disorder With Anxious Distress

Study ID

NCT07065240

Start date

Jun 19, 2025

Status verified date

Jul, 2026

Completion date

Mar, 2027

Anticipated

Primary completion date

Mar, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Participant is a male or female between 18 and 65 years of age, inclusive willing and able and have capacity to provide written informed consent.
  • Participants must have a primary diagnosis of MDD. Participants with a diagnosis of comorbid generalized anxiety disorder, social anxiety disorder, or panic disorder (with or without agoraphobia) may be included if not the focus of treatment over the past 6 months prior to Screening and the Investigator considers MDD to be the primary diagnosis at Screening and Baseline.
  • Eligible participants must have a current depressive episode of at least 4 weeks, but no greater than 18 months in duration prior to Screening.
  • Women of childbearing potential (WOCP) must not plan to become pregnant during the course of the study or be currently breastfeeding. WOCP agree to use an acceptable form of highly effective contraception during participation in the study and for 30 days after receiving the last dose of study treatment.
  • Body mass index (BMI) between 18 to 40 kg/m2, inclusive.
  • Participant is willing and able to refrain from the use of drugs of abuse.

Exclusion Criteria:

  • History of, or current presentation consistent with:

1. any depressive episode with psychotic or catatonic features.
2. any bipolar manic, hypomanic or mixed episode, and substance-induced (e.g., antidepressant-induced) manic, hypomanic/mixed episode.
3. bipolar disorder, including history of bipolar depression, or current presentation consistent with bipolar depression.
4. schizophrenia, schizoaffective, or other psychotic disorder.
5. obsessive-compulsive disorder.
6. any persistent neurocognitive disorder.
  • History of treatment-resistant depression defined as 2 or more failed treatments of adequate dose and duration in the current depressive episode.
  • Psychiatric hospitalization within current depressive episode.
  • Evidence or history of clinically significant diseases which can affect the patients' participation.
  • Previous history of intolerance or significant adverse effects, including drug allergy to allopregnanolone or any components of the SPT-300/placebo formulation.
  • Participant has a history of drug or alcohol use disorder.
  • Participants with a positive test for cannabinoids.
  • Clinically significant risk of suicide or harm to self or others.

Study Design

Enrollment

360 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: SPT-300

Participants will receive SPT-300 capsules once daily for 42 days

placebo comparator: Placebo

Participants will receive matching placebo once daily for 42 days

Interventions

SPT-300

A prodrug of allopregnanolone, a small molecule drug

Placebo

Placebo for SPT-300

Primary outcome measure

  • Change From Baseline to Day 42 in Hamilton Depression Rating Scale-17 (HAM-D-17) Total Score [ Time Frame: Baseline (Day 0) to Day 42 ]

Central Contacts and Locations

Central contacts

Clinical trial information desk

617-807-4062clinicaltrials@seaporttx.com

Locations

Seaport Investigator Site

Recruiting

Chino, California, United States, 91710

Seaport Investigator Site

Recruiting

Garden Grove, California, United States, 92845-2506

Seaport Investigator Site

Recruiting

Glendale, California, United States, 91206

Seaport Investigator Site

Recruiting

Redlands, California, United States, 92373

Seaport Investigator Site

Recruiting

San Jose, California, United States, 95124

Seaport Investigator Site

Recruiting

Cromwell, Connecticut, United States, 06416

Seaport Investigator Site

Recruiting

Jacksonville, Florida, United States, 32256

Seaport Investigator Site

Recruiting

Lauderhill, Florida, United States, 33319

Seaport Investigator Site

Recruiting

Orlando, Florida, United States, 32801

Seaport Investigator Site

Recruiting

Palm Bay, Florida, United States, 32905

Seaport Investigator Site

Recruiting

West Palm Beach, Florida, United States, 33407

Seaport Investigator Site

Recruiting

Atlanta, Georgia, United States, 30328

Seaport Investigator Site

Recruiting

Decatur, Georgia, United States, 30030

Seaport Investigator Site

Recruiting

Boston, Massachusetts, United States, 02116

Seaport Investigator Site

Recruiting

Russells Mills, Massachusetts, United States, 02747

Seaport Investigator Site

Recruiting

St Louis, Missouri, United States, 63141

Seaport Investigator Site

Recruiting

Brooklyn, New York, United States, 11235

Seaport Investigator Site

Recruiting

Cedarhurst, New York, United States, 11516

Seaport Investigator Site

Recruiting

New York, New York, United States, 10029

Seaport Investigator Site

Recruiting

Staten Island, New York, United States, 10314

Seaport Investigator Site

Recruiting

Independence, Ohio, United States, 44131

Seaport Investigator Site

Recruiting

North Canton, Ohio, United States, 44720

Seaport Investigator Site

Recruiting

Allentown, Pennsylvania, United States, 18104

Seaport Investigator Site

Recruiting

Media, Pennsylvania, United States, 19063

Seaport Investigator Site

Recruiting

Dallas, Texas, United States, 75231

Seaport Investigator Site

Recruiting

Irving, Texas, United States, 75062

Seaport Investigator Site

Recruiting

Richardson, Texas, United States, 75080

Seaport Investigator Site

Recruiting

Everett, Washington, United States, 98201

More Information

Sponsor

Seaport Therapeutics

Last update posted

Aug 17, 2026

Last verified

Jul, 2026

Keywords

  • Major Depressive Disorder
  • Depressive Disorder
  • Depression
  • Anxiety
  • Mood Disorders
  • BUOY-1 Study
  • SPT-300
  • LYT-300
  • GlyphAllo
  • Glyph Allopregnanolone

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-08. This information was provided to ClinicalTrials.gov by Seaport Therapeutics on 2026-08-17.