Major Depressive DisorderPhase 2GATE-251NCT07115329
A Phase 2 Study of Zelquistinel or Placebo for the Reduction of Symptoms of Major Depressive Disorder
A Phase 2 study testing Zelquistinel in people with Major Depressive Disorder, run by Syndeio Biosciences, Inc at 32 sites in United States.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 to 64 years
- Conditions the study is for
- Major Depressive Disorder
- What is being tested?
- Zelquistinel
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 164 participants
- Where
- 32 sitesUnited States
- Study dates
- 5 Jan 2026to Jun 2028
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 64 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Male or female subject.
- Aged 18 to 64 years, inclusive.
- Subject has a first episode or recurrent episode diagnosis of MDD, defined by the Diagnosis and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), ≥3 weeks and ≤18 months. The diagnosis of MDD will be made by a central rater using the Structured Clinical Interview for DSM-5 Clinical Trials version (SCID-5-CT).
- Subject has a HDRS-17 total score of ≥18 at the Screening Visit (V1) and Baseline Visit (V2) as assessed by a central rater, with no more than a 25% change from the Screening Visit (V1) to the Baseline Visit (V2)
- Subject has HARS total score ≥15 at the Screening Visit (V1) and predose at the Baseline Visit (V2), AND
- Subject has ISI total score ≥10 at the Screening Visit (V1) and predose at the Baseline Visit (V2).
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- Female subjects must meet 1 of the following:
- Surgically sterile or at least 2 years menopausal (ie, postmenopausal is defined as a woman with the absence of menses for at least 12 consecutive months). Menopausal status is to be confirmed by assessing the follicle stimulating hormone level at Screening Visit (V1), or,
- If a woman of childbearing potential, subject must use an acceptable method of birth control from date of Screening to the last evaluation at Day 71. Must have a documented negative point of care urine pregnancy test within 24 hours prior to first dosing.
- Male subjects, including those who are surgically sterile, must use a medically acceptable form of contraception from the time of randomization until the End of Week 6 Visit. Male subjects are strongly advised to inform female partners of the need for them to use highly effective birth control during this time period.
- 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.
- Provides written informed consent to participate in the study.
- Is able to communicate with investigational site personnel, able to complete patient-reported outcome measures and in the opinion of the Investigator, can be reliably rated on assessment scales.
- Have an appropriate severity of illness of at least moderately ill corresponding to a CGI-S score of ≥4 at the Screening and Baseline Visits (V1 and V2, respectively), as assessed by a central rater.
Who cannot join
- A subject who meets any of the following criteria will be excluded from study participation:
- Evidence of treatment-resistant MDD, defined by having an inadequate response (≤25%) to 2 or more different medications approved for the treatment of MDD at an adequate dose (per locally approved label) for an adequate duration during the current episode using the Massachusetts General Hospital Antidepressant Treatment Rating Questionnaire (MGH ATRQ) assessed by a site rater.
- Current DSM-5 diagnosis of bipolar (or related disorders), antisocial personality disorder, obsessive compulsive disorder, borderline personality disorder,attention-deficit/ hyperactivity disorder, post-traumatic stress disorder, or panic attacks. Subjects not meeting full DSM-5 criteria for borderline personality disorder but exhibiting recurrent suicidal gestures, threats, or self-mutilating behaviors should also be excluded.
- Subject has a current or prior DSM-5 diagnosis of a psychotic disorder, or MDD with psychotic features.
- Subject has a score of >4 on the CADSS at the Screening Visit (V1).
- Active seizure disorder.
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- Traumatic brain injury with current signs or symptoms.
- Treatment with esketamine or ketamine, any psychedelic agent, or any experimental agent being evaluated to treat depression, whether as an antidepressant or for other use, within the past 12 months.
- o Treatment with any other experimental agents not used to treat depression within the past 3 months.
- Concomitant treatment with other Food and Drug Administration (FDA)-approved antidepressants or adjuvant agents or enhancers such as dextromethorphan, antipsychotics, mood stabilizers, sedatives, stimulants, or benzodiazepines. Subject must discontinue concomitant treatment at least 14 days prior to the Baseline Visit.
- o Subjects may continue anxiolytic agents, except for drugs that are also used to treat depression. Subjects may continue sleep aids, so long as they have been on a stable dose for at least 3 months and do not intend to change dose during the Double-Blind Treatment Period (Week 1 [Day 1] through End of Week 6). However, trazodone must be discontinued for at least 14 days prior to the Baseline Visit.
- Use of cannabis or cannabis-derived molecules, including tetrahydrocannabinol (THC), whether natural or chemically-synthesized, including hemp seed oil and cannabidiol (CBD) products (eg, gummies). Subject must discontinue the use of such products at least 14 days prior to the Baseline Visit, and THC must be below the limit of detection at the Baseline Visit.
- Positive test for any drug of abuse.
- Treated with any medical device or digital therapeutics for MDD, anxiety, insomnia, or other CNS indications within 90 days of screening in this study.
- History of electroconvulsive therapy, vagus nerve stimulation, deep brain stimulation, or repetitive transcranial magnetic stimulation within the past 5 years or has had a failure of response to electroconvulsive therapy at any time.
- Subject has clinically significant renal dysfunction as assessed by the estimated glomerular filtration rate (eGFR) <70 mL/min/1.73 m2 using the Chronic Kidney Disease Epidemiology Collaboration-creatinine (CKD-EPI creatinine) methodology.
- Subject has liver protein and enzyme (alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, total bilirubin, lactate dehydrogenase) test result >1.5 × upper limit of normal (subjects with a diagnosis of Gilbert's Syndrome may be eligible if no liver function or enzyme test results other than total bilirubin are >1.5 × upper limit of normal).
- Subject has resting radial pulse rate (supine) <60 or >100 bpm at the Screening Visit or predose Baseline, based on a single assessment.
- Subject has resting diastolic blood pressure <50 mmHg at the Screening Visit or predose Baseline.
- Subject has PR interval >250 msec at the Screening Visit or predose Baseline, or QT corrected for heart rate by Fridericia's formula (QTcF) or QT corrected for heart rate by Bazett's formula (QTcB) interval >450 msec in males or >470 msec in females, or QRS interval >120 msec, based on a single reading.
- Evidence of alcohol abuse (>4 units of alcohol on most days; 1 unit=½ pint of beer, 1 glass of wine, or 1 ounce of hard liquor/spirits) or a positive saliva alcohol screen at Screening and predose at the Baseline Visit. Alcohol consumption should be avoided for at least 24 hours prior to Baseline Visit.
- Abuse of illicit substances by DSM-5 definition of substance use disorder within the 12 months prior to the Screening Visit.
- Use of nicotine containing products (eg, cigarettes, cigars, vaping, and pipes). Nicotine containing products must be discontinued for at least 14 days prior to randomization, and nicotine or cotinine (metabolite) must be negative at Baseline.
- Use of barbiturates. Prescribed barbiturates may be continued so long as the subject has been on a stable dose for at least 3 months and the dose may not change during the Double-Blind Treatment Period.
- HIV infection, COVID-19 infection,or active hepatitis B or C, syphilis, or other ongoing infectious disease at the Screening Visit (V1).
- Has laboratory evidence of hypothyroidism at Screening Visit (V1) as measured by thyroid stimulating hormone (TSH) and reflex free thyroxine (T4). If TSH is abnormal and reflex T4 is normal, the subject may be included.
- Has current unstable diabetes or glycosylated hemoglobin (HbA1c) >7% at Screening Visit (V1).
- Currently pregnant, planning to become pregnant during the course of the study, or nursing.
- Currently working a night shift or may be required to work night shift during the course of this study, from Screening through the End of Week 6 Visit or completion of the final polysomnography for subjects who elect to participate in the polysomnography sessions.
- Malignancy in the last 5 years, with the exception of nonmetastatic basal cell or squamous cell carcinoma of the skin or localized carcinoma in situ of the cervix.
- Subject has received new onset psychotherapy or had a change in the intensity of psychotherapy within 4-weeks prior to the Screening Visit (V1).
- Currently taking prohibited prescription or over-the-counter medications including herbal therapies (eg, echinacea, ginseng, ginkgo, elderberry, turmeric, ginger, valerian, chamomile, or St John's wort) and THC- or cannabis-containing products (see Exclusion Criterion 9), which may interfere with the required study psychiatric assessments.
- History of allergy, sensitivity, or intolerance to GATE-251 or NMDAR ligands including ketamine, dextromethorphan, memantine, methadone, dextropropoxyphene, or ketobemidone.
- Previously participated in this study or Study GATE-251-C-202 or currently enrolled in any other clinical study.
- Body mass index of >40 kg/m2 at the Screening Visit (V1).
- Subject is an employee of Worldwide or the Investigator or study site with direct involvement in the study or other studies under the direction of that Investigator or study site; a family member of an employee of the Investigator; or an employee of Gate Neurosciences, Inc. or a family member of an employee.
- In the opinion of the Investigator, the subject has a significant risk for suicidal behavior during the course of participation in the study, OR
- At the Screening Visit (V1), the subject scores "Yes" on Items 4 or 5 in the Suicidal Ideation section of the C-SSRS with reference to a 6-month period prior to Screening Visit (V1), or
- At the Screening Visit (V1), the subject has had 1 or more suicidal attempts with reference to a 2-year period prior to Screening Visit (V1), or
- The subject is considered to be an imminent danger to themself or others, or
- At the Baseline Visit (V2), the subject scores "Yes" on Items 4 or 5 in the Suicidal Ideation section of the C-SSRS
- The subject is judged by the Investigator or the Worldwide and Sponsor medical monitors to be appropriate for the study for any reason
Trial locations and contacts
32 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Sharon Ortiz contact
32 sites in 1 country
United States32 sites, 30 recruiting
- Not yet recruiting
Lehigh Center for Clinical Research
Allentown, Pennsylvania, 18103
- Recruiting
Elevate Synapsis, LLC
Atascocita, Texas, 77346
Matthew B, (281) 339-8401, mbrams@elevateclinical.com
- Recruiting
Synapsis Bio
Atascocita, Texas, 77346
MBrams, mbrams@elevateclinical.com
- Not yet recruiting
Neurobehavioral Research, Inc
Cedarhurst, New York, 11516
- Recruiting
EmVenio Research
Chicago, Illinois, 60622
Mitchell G, (312)-238-9779, mitchell.glaser@emvenio.com
- Not yet recruiting
Adams Clinical Dallas
DeSoto, Texas, 75115
- Recruiting
Psychiatric Consultants, PC
Franklin, Tennessee, 37067
James H, 615-807-4023, hartc@mac.com
- Not yet recruiting
Insight Clinical Trials LLC
Independence, Ohio, 44131
- Not yet recruiting
Clinical Neuroscience Solutions, Inc
Jacksonville, Florida, 32256
- Recruiting
Tandem Clinical Research
Metairie, Louisiana, 70006
Angela T, 504-934-8092, drtraylor@tandemclinicalresearch.com
- Not yet recruiting
Premier Clinical Research Institute Inc
Miami, Florida, 33122
- Recruiting
Catalina Research Institute, LLC
Montclair, California, 91763
Stephen V, 909-590-8409, stephen.volk@elixiahealth.com
- Terminated
Scranton Medical Institute, LLC
Moosic, Pennsylvania, 18507
- Recruiting
Aqualane Clinical Research
Naples, Florida, 34105
Matthew B, 239-529-6780, info@aqualaneresearch.com
- Recruiting
IMA Clinical Research - NYC Midtown
New York, New York, 10036
E. Shalenberg, 646-722-6214, eli.shalenberg@imaresearch.com
- Recruiting
IMA Clinical Research - NYC Uptown
New York, New York, 10128
Jason C, (212) 595-5012, jason.careri@imaresearch.com
- Recruiting
Excell Research, Inc
Oceanside, California, 92056
Sherry S, 760-758-2222, soefjemd@excellresearch.com
- Recruiting
Adams Clinical
Philadelphia, Pennsylvania, 19104
Cassie B, 267-207-2511, cblanchard@adamsclinical.com
- Recruiting
NoesisPharma, LLC
Phoenix, Arizona, 85028
John P, 602-795-1834, jprater@noesispharma.com
- Recruiting
UNC Health Rex
Raleigh, North Carolina, 27607
SVaishnavi, sandeep.vaishnavi@unchealth.unc.edu
- Recruiting
Anderson Clinical Research
Redlands, California, 92374
Donald A, 909-792-9007, dla@andersonstudies.com
- Recruiting
EquiPath Health and Research Tampa Bay, LLC
Riverview, Florida, 33578
Conrado B, 727-271-7738, cbeckles@equipathhealth.com
- Recruiting
Rochester Center for Behavioral Medicine
Rochester Hills, Michigan, 48307
JYoung, 248-608-8800, jyoung@rcbm.net
- Withdrawn
Sunstone Therapies
Rockville, Maryland, 20850
- Recruiting
Studyops Inc
San Francisco, California, 94102
Erikson-Ridout, 415-987-4722, kridout@studyops.com
- Recruiting
Lumos Clinical Research Center
San Jose, California, 95124
Sarbani M, 408-402-5424, md@lumosclinical.com
- Recruiting
Denali Health Atlanta, LLC
Stone Mountain, Georgia, 30038
Maria J, 217-933-2108, drmariajmd@denali-health.com
- Recruiting
Continental Clinical Solutions
Towson, Maryland, 21204
Marilyn M, 410-616-9566, mmartin@continentalclinical.com
- Recruiting
Del Sol Research Management
Tucson, Arizona, 85710
S. Bupp, (520) 617-2203, mailto:sbuppmd@delsolresearch.com
- Not yet recruiting
Sunwise Clinical Research
Walnut Creek, California, 94596
- Recruiting
Neuroscience Research Institute
West Palm Beach, Florida, 33407
Danesh A, 561-578-8573, dalam@neuroscienceresearchinstitute.com
- Recruiting
Vitalix Clinical
Worcester, Massachusetts, 01608
James, MD, 413-363-5206, jcarroll@vitalixclinical.com
About this study
Official title: 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
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 zelquistinel1)?
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.
Read the detailed description
This is a Phase 2 multicenter, randomized, double-blind, placebo-controlled, parallel-group, fixed dose clinical trial designed to evaluate the safety and efficacy of zelquistinel versus placebo in subjects with symptoms of major depressive disorder. Each subject will participate in this study up to 98 days: up to 28 days for screening, 42 days for double-blind treatment, and a 4-week follow-up period. Subjects will return to the clinic one time each week to have the severity of their depression assessed using the Hamilton depression rating scale-17. Adverse events that occurred since the last study visit will be recorded.
- Conditions
- Major Depressive Disorder
- Being tested
- Zelquistinel
- Keywords
- zelquisitinel, GATE-251, N-Methyl-D-aspartate receptor positive allosteric modulator, NMDA receptor positive allosteric modulator
- Medical subject headings
- Depressive Disorder, Major
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ZelquistinelDrug
Also called GATE-251
Zelquistinel is a positive allosteric modulator of the N-Methyl-D-Aspartate (NMDA) receptor
| Study group | Role | What they receive |
|---|---|---|
| zelquisitinel (GATE-251 ) | Experimental | zelquistinel (GATE-251) will be administered as a single 6 mg oral tablet one time each week for 6 weeks. Receives: Drug: Zelquistinel |
| Placebo | Placebo comparator | Placebo tablet identical in appearance to the experimental treatment tablet, administered as as a single oral tablet one time each week for 6 weeks. Receives: Drug: Zelquistinel |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in the Hamilton Depression Rating Scale-17 (HDRS-17) score compared to Placebo
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
Measured: Change in score from baseline to 6 wweeks
Secondary outcomes (1)
Change in the Clinical Global Impressions - Severity (CGI-S) score compared to placebo
The CGI-S is a 7-level rating scale used by a clinician to gauge depression severity. The range of scores is 0-7 with lower scores indicating a better outcome
Measured: Change in score from baseline to 6 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Aug 2025
- Study start5 Jan 2026
- Primary completion30 Mar 2028 (estimated)
- Study completionJun 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Major Depressive DisorderStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Phase 2 multicenter, randomized, double-blind, placebo-controlled, parallel-group, fixed dose clinical trial
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 164 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Syndeio Biosciences, Inc
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Worldwide Clinical Trials
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07115329
- Sponsor's protocol ID
- GATE-251-C-203
- Acronym
- GATE-251
- Status last verified
- Jul 2026
- First submitted
- 4 Aug 2025
- Last updated
- 27 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 27 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT07115329
- Acronym / sponsor ID
- GATE-251 / GATE-251-C-203
- Conditions
- Major Depressive Disorder
- Keywords
- zelquisitinel, GATE-251, N-Methyl-D-aspartate receptor positive allosteric modulator, NMDA receptor positive allosteric modulator
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 164 participants (estimated)
- Lead sponsor
- Syndeio Biosciences, IncIndustry (pharma, biotech, devices)
- Collaborators
- Worldwide Clinical Trials
- Study start
- 5 Jan 2026 (actual)
- Primary completion
- 30 Mar 2028 (estimated)
- Study completion
- Jun 2028 (estimated)
- First posted
- 11 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 zelquistinel1)?
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.
Detailed description
This is a Phase 2 multicenter, randomized, double-blind, placebo-controlled, parallel-group, fixed dose clinical trial designed to evaluate the safety and efficacy of zelquistinel versus placebo in subjects with symptoms of major depressive disorder. Each subject will participate in this study up to 98 days: up to 28 days for screening, 42 days for double-blind treatment, and a 4-week follow-up period. Subjects will return to the clinic one time each week to have the severity of their depression assessed using the Hamilton depression rating scale-17. Adverse events that occurred since the last study visit will be recorded.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Phase 2 multicenter, randomized, double-blind, placebo-controlled, parallel-group, fixed dose clinical trial
| Arm | Type | Receives |
|---|---|---|
| zelquisitinel (GATE-251 ) | Experimental | Drug: Zelquistinelzelquistinel (GATE-251) will be administered as a single 6 mg oral tablet one time each week for 6 weeks. |
| Placebo | Placebo comparator | Drug: ZelquistinelPlacebo tablet identical in appearance to the experimental treatment tablet, administered as as a single oral tablet one time each week for 6 weeks. |
Who may qualify
- Ages
- 18 to 64 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (14 listed)
- Male or female subject.
- Aged 18 to 64 years, inclusive.
- Subject has a first episode or recurrent episode diagnosis of MDD, defined by the Diagnosis and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), ≥3 weeks and ≤18 months. The diagnosis of MDD will be made by a central rater using the Structured Clinical Interview for DSM-5 Clinical Trials version (SCID-5-CT).
- Subject has a HDRS-17 total score of ≥18 at the Screening Visit (V1) and Baseline Visit (V2) as assessed by a central rater, with no more than a 25% change from the Screening Visit (V1) to the Baseline Visit (V2)
- Subject has HARS total score ≥15 at the Screening Visit (V1) and predose at the Baseline Visit (V2), AND
Key exclusion criteria (42 listed)
- A subject who meets any of the following criteria will be excluded from study participation:
- Evidence of treatment-resistant MDD, defined by having an inadequate response (≤25%) to 2 or more different medications approved for the treatment of MDD at an adequate dose (per locally approved label) for an adequate duration during the current episode using the Massachusetts General Hospital Antidepressant Treatment Rating Questionnaire (MGH ATRQ) assessed by a site rater.
- Current DSM-5 diagnosis of bipolar (or related disorders), antisocial personality disorder, obsessive compulsive disorder, borderline personality disorder,attention-deficit/ hyperactivity disorder, post-traumatic stress disorder, or panic attacks. Subjects not meeting full DSM-5 criteria for borderline personality disorder but exhibiting recurrent suicidal gestures, threats, or self-mutilating behaviors should also be excluded.
- Subject has a current or prior DSM-5 diagnosis of a psychotic disorder, or MDD with psychotic features.
- Subject has a score of >4 on the CADSS at the Screening Visit (V1).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ZelquistinelAlso: GATE-251Zelquistinel is a positive allosteric modulator of the N-Methyl-D-Aspartate (NMDA) receptor | Drug | Placebo, zelquisitinel (GATE-251 ) |
Primary outcome
Change in the Hamilton Depression Rating Scale-17 (HDRS-17) score compared to Placebo
Time frame: Change in score from baseline to 6 wweeks
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
1 secondary outcome
Change in the Clinical Global Impressions - Severity (CGI-S) score compared to placebo
Time frame: Change in score from baseline to 6 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Jul 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Sharon Ortiz contact
32 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Zelquistinel in people with Major Depressive Disorder, run by Syndeio Biosciences, Inc at 32 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 14 inclusion and 42 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 27 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 32 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Karen Raudibaugh (781-786-1545, karen.raudibaugh@syndeio.bio), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in the Hamilton Depression Rating Scale-17 (HDRS-17) score compared to Placebo (time frame: Change in score from baseline to 6 wweeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Jul 2026.