NCT06547489 · Syndeio Biosciences, Inc
GATE-251 or Placebo for the Reduction of Symptoms of Major Depressive Disorder
What this study is about
The goal of this clinical trial is to learn if GATE-251 works to treat depression in adults. It will also learn about the safety of GATE-251.
View original scientific description
The goal of this clinical trial is to learn if GATE-251 works to treat depression in adults. It will also learn about the safety of GATE-251. The main questions it aims to answer are: Does GATE-251 reduce depression scores in participants compared to participants who take a placebo (a look-alike tablet that contains no GATE-251)? What medical problems are observed in participants who take GATE-251? Participants will take one tablet of GATE-251 or placebo every week for 6 weeks.
Interventions
DRUG
Zelquistinel
Zelquistinel is a positive allosteric modulator of the N-Methyl-D-Aspartate (NMDA) receptor
Primary outcome measures
Change in the Hamilton Depression Rating Scale-17 (HDRS-17) score compared to placebo
Time frame: Change in score from predose baseline to end of week 6
HDRS-17 is used to assess the severity of depression. The range of scores for the HDRS-17 is 0 - 52 with lower scores indicating a better outcome
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Each subject must meet all of the following inclusion criteria to be eligible to participate in the study: 1. Male or female subjects. 2. Aged 18 to 64 years, inclusive. 3. Subject has a diagnosis of major depressive disorder (MDD), single or recurrent episode, defined by the Diagnosis and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5); if single episode, the duration must be ≥3 weeks and ≤18 months. The diagnosis of MDD will be made by a site psychiatrist and supported by the Structured Clinical Interview for DSM-5 - Clinical Trials version (SCID-5-CT) and confirmed by remote, independent raters from the Massachusetts General Hospital Clinical Trials Network and Institute with a State versus trait, Assessability, Face validity, Ecological validity, and Rule of three Ps (pervasive, persistent, and pathological) (SAFER) interview: 1. The current depressive episode is ≥3 weeks and ≤18 months in duration prior to the Screening Visit (V1); 2. Hav
Where
- Birmingham, Alabama
- Huntsville, Alabama
- Encino, California
- Irvine, California
- Los Angeles, California
- Upland, California
- Walnut Creek, California
- Colorado Springs, Colorado
- Denver, Colorado
- Farmington, Connecticut
- Jacksonville, Florida
- Margate, Florida
And 21 more locations — see the full list below.
Collaborators
Worldwide Clinical Trials
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 7, 2026 · Source of record for eligibility and locations