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

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Seaport Therapeutics Inc.

Participant type

Patients

Age range

18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Psychiatry and Psychology [F] - Mental Disorders [F03]

Trial duration

26 Nov 2025 → ongoing

Decision date (initial)

2025-11-11

Transition trial

No

Low-intervention

No

Rare-disease indication

No

Vulnerable population

Yes

Funding sources

Seaport Therapeutics · Seaport Therapeutics

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Therapy, Others, Safety, Efficacy

To evaluate the safety and tolerability of oral doses of SPT 300 in participants with MDD, with or without anxious distress

Secondary objectives 1

1. To further evaluate the effectiveness of SPT-300 as monotherapy in participants with MDD, with or without anxious distress, with respect to the following: o Depressive symptoms o Anxiety symptoms o Overall illness severity o Overall functioning o Quality of life

Conditions and MedDRA coding

Major Depressive Disorder (MDD), with or without Anxious Distress

Regulatory references

Plan to share IPD

No

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 6

1. Participant who completed treatment in Study SPT-300-2024-203-OUS (ie, participant who competed Visit 6 [Day 42] of Study SPT-300-2024-203-OUS)
2. Participant must be able, willing, and have capacity to provide written informed consent prior to any study procedures and should agree to comply with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol.
3. 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 at least an acceptable form of highly effective contraception during participation in the study and for 30 days after receiving the last dose of study treatment.
4. Male participants and their female partners should agree to use at least an acceptable method of effective contraception for the duration of study and for at least 30 days after receiving the last dose of the study treatment.
5. Participant is willing and able to refrain from the use of drugs of abuse (including recreational cannabinoids/medical cannabinoids) and alcohol for the duration of the study.
6. Willing and able to comply with the scheduled visits, treatment plan, laboratory tests, and other study procedures and requirements.

Exclusion criteria 3

1. Participants who, in the opinion of the Investigator, medical monitor, or Sponsor, should not participate in the study.
2. Participants who, in the judgment of the Investigator, were noncompliant with trial procedures or with study treatment administration during the double-blind study.
3. 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.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 2

1. Incidence, severity, and duration of treatment-emergent adverse events, serious adverse events, and incidence of clinically significant vital signs, electrocardiograms, safety laboratory, and physical examination findings
2. Suicidal ideation and behavior using the Columbia Suicide Severity Rating Scale

Secondary endpoints 1

1. Change from Baseline to Visit 6 (Study Day 42) in the following: • HAM-D-17 total score • CGI-S • Hamilton Anxiety Rating Scale • PGI-S • Sheehan Disability Scale • The Quality of Life, Enjoyment, and Satisfaction Questionnaire-Short Form

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Seaport Therapeutics Inc.

Sponsor organisation

Seaport Therapeutics Inc.

Address

101 Seaport Boulevard Floor 12

City

Boston

Postcode

02210-2149

Country

United States

Scientific contact point

Organisation

Seaport Therapeutics Inc.

Contact name

Clinical trial information desk

Public contact point

Organisation

Seaport Therapeutics Inc.

Contact name

Clinical trial information desk

Third parties 13

Locations

7 EU/EEA countries · 35 investigational sites

By country

Investigational sites

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 133 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

6 submissions — initial application plus substantial / non-substantial modifications