Recruiting

GATE-251GATE-251 for Symptom Reduction in Major Depressive Disorder

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What is being tested

Zelquistinel

Drug
Who is being recruted

Mental Disorders+1

+ Depressive Disorder, Major

+ Depressive Disorder

From 18 to 64 Years
+41 Eligibility Criteria
See all eligibility criteria
How is the trial designed

Treatment Study

Placebo-ControlledPhase 2
Interventional
Study Start: February 2025
See protocol details

Summary

Principal SponsorSyndeio Biosciences, Inc
Study ContactKaren RaudibaughMore contacts
Last updated: March 21, 2026
Sourced from a government-validated database.Claim as a partner

Study start date: February 3, 2025

Actual date on which the first participant was enrolled.

This clinical trial aims to evaluate the safety and efficacy of an experimental drug, Zelquistinel, in reducing symptoms of Major Depressive Disorder in adults. The study is in its second phase, indicating that it has already passed initial safety tests. It's important because it could potentially lead to a new treatment option for those suffering from depression, a condition that currently affects millions worldwide and often lacks effective treatments. During the trial, participants will be involved for up to 98 days, which includes a screening period, a double-blind treatment period, and a follow-up period. Participants will visit the clinic weekly to have their depression severity assessed using the Hamilton Depression Rating Scale-17. This scale helps to measure the severity of depression, with lower scores indicating better outcomes. Any adverse events that occur during the study will be recorded to evaluate the safety of Zelquistinel.

Official TitleA Phase 2, Multicenter, Randomized, Double-blind Evaluation of the Efficacy and Safety of Oral GATE-251 or Placebo for the Reduction of Symptoms of Major Depressive Disorder in Adults
NCT06547489
Principal SponsorSyndeio Biosciences, Inc
Study ContactKaren RaudibaughMore contacts
Last updated: March 21, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details

164 patients to be enrolled

Total number of participants that the clinical trial aims to recruit.

Treatment Study

These studies test new ways to treat a disease, condition, or health issue. The goal is to see if a new drug, therapy, or approach works better or has fewer side effects than existing options.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria

Any sex

Biological sex of participants that are eligible to enroll.

From 18 to 64 Years

Range of ages for which participants are eligible to join.

Healthy volunteers not allowed

If individuals who are healthy and do not have the condition being studied can participate.

Conditions

Pathology

Mental DisordersDepressive Disorder, MajorDepressive DisorderMood Disorders

Criteria

12 inclusion criteria required to participate
Ability to understand the nature and requirements of the study and is willing to comply with the study restrictions and agree to return for the required assessments.
Male or female subjects.
Subject must be medically stable by physical examination, medical history, vital signs, laboratory evaluations, and 12-lead electrocardiogram performed at the Screening Visit (V1) and Baseline (V2). If abnormalities are found, the subject may be included if the Investigator, contract research organization (CRO) and sponsor medical monitors judge the abnormalities to be not clinically significant.
Subject has Insomnia Severity Index (ISI) total score ≥15 at the Screening Visit (V1) and predose at the Baseline Visit (V2)
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29 exclusion criteria prevent from participating
Treatment with any experimental antidepressant agent or treatment with a psychedelic agent in an FDA-approved clinical study within the past 12 months.
Received another investigational drug or device within 90 days of screening in this study.
The subject is judged by the Investigator or CRO and Sponsor medical monitors to be inappropriate for the study for any reason.
Body mass index of >40 kg/m2 at the Screening Visit (V1).
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Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives

2 intervention groups are designated in this study

50% chance of being blinded to the placebo group

Treatment Groups

Group I

Placebo
Placebo tablet identical in appearance to the experimental treatment tablet, administered as as a single oral tablet one time each week for 6 weeks.

Group II

Experimental
zelquistinel (GATE-251) will be administered as a single 10 mg oral tablet one time each week for 6 weeks.

Study Objectives

Primary Objectives

Secondary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.

This study has 34 locations

Recruiting

University of Alabama at Birmingham

Birmingham, United StatesOpen University of Alabama at Birmingham in Google Maps
Recruiting

University of Alabama at Birmingham-Huntsville

Huntsville, United States
Recruiting

Irvine Clinical Research

Irvine, United States
Recruiting

CalNeuro Research Group

Los Angeles, United States
Recruiting
34 Study Centers