Actively Recruiting
Zelquistinel or Placebo for the Reduction of Symptoms of Major Depressive Disorder
Led by Syndeio Biosciences, Inc · Updated on 2026-05-05
164
Participants Needed
34
Research Sites
147 weeks
Total Duration
On this page
Sponsors
S
Syndeio Biosciences, Inc
Lead Sponsor
W
Worldwide Clinical Trials
Collaborating Sponsor
AI-Summary
What this Trial Is About
The goal of this clinical trial is to learn if zelquistinel works to treat depression in adults. It will also learn about the safety of zelquistinel. The main questions it aims to answer are: Does zelquistinel reduce depression scores in participants compared to participants who take a placebo (a look-alike tablet that contains no zelquistinel)? What medical problems are observed in participants who take zelquistinel? Participants will take one tablet of zelquistinel or placebo every week for 6 weeks. Participants will visit the clinic every week of the 6 week period to have the severity of their depression evaluated.
CONDITIONS
Official Title
Zelquistinel or Placebo for the Reduction of Symptoms of Major Depressive Disorder
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Male or female aged 18 to 64 years
- Diagnosis of major depressive disorder (single or recurrent episode) lasting 3 weeks to 18 months
- Moderate to severe illness with CGI-S score of 4 or higher at screening and baseline visits
- Hamilton Depression Rating Scale-17 score of 22 or higher with stable scores between screening and baseline
- Hamilton Anxiety Rating Scale score of 15 or higher at screening and baseline
- Insomnia Severity Index score of 15 or higher at screening and baseline
- Female participants must be surgically sterile, menopausal for at least 2 years, or use acceptable birth control with a negative pregnancy test
- Male participants must use medically acceptable contraception
- Medically stable as determined by physical exam, medical history, vital signs, labs, and ECG
- Ability to understand study requirements and comply with study restrictions
- Willingness to provide written informed consent
- Ability to communicate with study staff and complete patient-reported measures
You will not qualify if you...
- Treatment-resistant major depressive disorder with inadequate response to 2 or more approved medications
- Current diagnosis of bipolar disorder, antisocial personality disorder, obsessive compulsive disorder, borderline personality disorder, or ADHD
- Current or prior diagnosis of psychotic disorder or MDD with psychotic features
- Current use of FDA-approved antidepressants, antipsychotics, mood stabilizers, sedatives, stimulants, esketamine, ketamine, or psychedelics; certain anxiolytics and sleep aids allowed if stable
- Use of cannabis or related products within 14 days before baseline
- Participation in other experimental antidepressant or psychedelic studies within 12 months
- History of electroconvulsive therapy or similar treatments within 5 years or failure to respond to ECT
- Significant kidney or liver dysfunction
- Abnormal heart rate, blood pressure, or ECG measurements
- Evidence of alcohol abuse or positive alcohol screen
- Substance abuse including nicotine use within 14 days prior to randomization
- Positive drug abuse test (except prescribed barbiturates)
- Active infections including HIV, COVID-19, hepatitis B or C, or syphilis
- Laboratory evidence of hypothyroidism or unstable diabetes
- Pregnancy, nursing, or planning pregnancy during study
- Night shift work during study
- Recent malignancy except certain skin or cervical cancers
- Recent changes in psychotherapy
- Use of prohibited medications or herbal therapies
- Allergies or intolerance to study drug or related compounds
- Participation in other investigational drug or device studies within 90 days
- Body mass index over 40 kg/m2
- Employment or family relations with study staff or sponsor
- Significant risk of suicidal behavior or recent suicidal attempts
- Judged inappropriate for study participation by investigators or monitors
AI-Screening
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Trial Site Locations
Total: 34 locations
1
University of Alabama at Birmingham
Birmingham, Alabama, United States, 35294
Actively Recruiting
2
University of Alabama at Birmingham-Huntsville
Huntsville, Alabama, United States, 35801
Actively Recruiting
3
Wr-Pri, Llc
Encino, California, United States, 91316
Withdrawn
4
Irvine Clinical Research
Irvine, California, United States, 92614
Actively Recruiting
5
CalNeuro Research Group
Los Angeles, California, United States, 90025
Actively Recruiting
6
Pacific Clinical Research Management Group LLC
Upland, California, United States, 91786
Terminated
7
Sunwise Clinical Research LLC
Walnut Creek, California, United States, 94549
Actively Recruiting
8
MCB Clinical Research Centers, Inc.
Colorado Springs, Colorado, United States, 80910
Actively Recruiting
9
Mountain View Clinical Research
Denver, Colorado, United States, 80209
Actively Recruiting
10
University of Connecticut School of Medicine Psychiatry Department
Farmington, Connecticut, United States, 06030
Actively Recruiting
11
Clinical Neuroscience Solutions, Inc.
Jacksonville, Florida, United States, 32256
Actively Recruiting
12
D&H Pompano Research Center, LLC
Margate, Florida, United States, 33063
Actively Recruiting
13
Premier Clinical Research Institute, Inc.
Miami, Florida, United States, 33122
Actively Recruiting
14
Miami Dade Medical Research Institute
Miami, Florida, United States, 33176
Actively Recruiting
15
Clinical Neuroscience Solutions, Inc.
Orlando, Florida, United States, 32801
Actively Recruiting
16
CenExel iRS (iResearch Savannah)
Savannah, Georgia, United States, 31405
Actively Recruiting
17
Revive Research Institute
Elgin, Illinois, United States, 60123
Withdrawn
18
KUMC-Wichita
Wichita, Kansas, United States, 66160
Actively Recruiting
19
Quantum Research Associates Corp.
Louisville, Kentucky, United States, 40218
Actively Recruiting
20
Boston Clinical Trials
Boston, Massachusetts, United States, 02131
Withdrawn
21
Mayflower Clinical
Russells Mills, Massachusetts, United States, 02747
Actively Recruiting
22
Vector Clinical Trials
Las Vegas, Nevada, United States, 89128
Actively Recruiting
23
Neurobehavioral Research, Inc.
Cedarhurst, New York, United States, 11516
Actively Recruiting
24
Insight Clinical Trials LLC
Independence, Ohio, United States, 44131
Actively Recruiting
25
Sooner Clinical Research, Inc.
Oklahoma City, Oklahoma, United States, 73116
Withdrawn
26
Lehigh Center for Clinical Research
Allentown, Pennsylvania, United States, 18103
Actively Recruiting
27
Clinical Neuroscience Solutions, Inc.
Memphis, Tennessee, United States, 38119
Active, Not Recruiting
28
Austin Clinical Trial Partners
Austin, Texas, United States, 78737
Actively Recruiting
29
InSite Clinical Research, LLC
DeSoto, Texas, United States, 75115
Actively Recruiting
30
Baylor College of Medicine, Psychiatry and Behavioral Sciences
Houston, Texas, United States, 77030
Withdrawn
31
Clinical Trials of Texas LLC
San Antonio, Texas, United States, 78229
Withdrawn
32
Grayline Research Center
Wichita Falls, Texas, United States, 76309
Actively Recruiting
33
Andes Clinical Research
Orem, Utah, United States, 84097
Actively Recruiting
34
Northwest Clinical Research Center
Bellevue, Washington, United States, 98007
Withdrawn
Research Team
K
Karen Raudibaugh
CONTACT
K
Kelly Kosko
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
QUADRUPLE
Allocation
RANDOMIZED
Model
PARALLEL
Primary Purpose
TREATMENT
Number of Arms
2
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