What is Zelquistinel studying for major depressive disorder?

Zelquistinel is being studied to see if it can reduce symptoms of major depressive disorder in adults. This trial compares zelquistinel to a placebo to evaluate changes in depression severity and to monitor safety. The study is sponsored by Syndeio Biosciences, Inc and aims to better understand treatment options for depression.

Who may be eligible for this major depressive disorder clinical trial?

Adults aged 18 to 64 with a confirmed diagnosis of major depressive disorder lasting between 3 weeks and 18 months may be eligible. Both males and females can participate, with females required to use birth control if of childbearing potential. Participants should have moderate depression severity and meet other health criteria. Please review eligibility criteria for more details.

Is there any cost to participate in this major depressive disorder clinical trial?

Study-related care, including the study drug or procedure and all trial visits, is provided at no cost. However, personal travel expenses to attend study visits may vary and might not be covered. Participants should consider their own travel and lodging costs when joining the trial.

Actively Recruiting

Phase 2

Age: 18Years - 64Years

All Genders

ID07115329

Phase 2 Study on the Safety and Effectiveness of Zelquistinel Compared to Placebo for Treating Major Depressive Disorder in Adults Aged 18 to 64

Led by Syndeio Biosciences, Inc · Updated on 2026-07-27

164

Participants Needed

Research Sites

9 weeks

Total Duration

AI-Summary

What this Trial Is About

Researchers are evaluating zelquistinel, a drug aimed at reducing symptoms of major depressive disorder in adults aged 18 to 64 years. This Phase 2 clinical trial compares the effects and safety of zelquistinel to a placebo in participants diagnosed with major depressive disorder. The study will focus on changes in depression severity and monitor any medical issues that arise during treatment. Participants will take one tablet of either zelquistinel or placebo once a week for six weeks. The trial includes a screening period of up to 28 days, followed by a 42-day treatment phase, and then a four-week follow-up period. During treatment, participants will visit the clinic weekly to receive their dose and have their depression symptoms assessed using the Hamilton Depression Rating Scale-17. Throughout the study, participants will have their depression severity regularly evaluated, along with monitoring for adverse events or side effects. The study lasts up to 98 days, including screening, treatment, and follow-up. Researchers will measure changes in depression scores from the beginning to the end of treatment and monitor overall safety during this time.

CONDITIONS

Brief Title

A Phase 2 Study of Zelquistinel or Placebo for the Reduction of Symptoms of Major Depressive Disorder

Who Can Participate

Age: 18Years - 64Years

All Genders

Eligibility Criteria

You may qualify if you...

Male or female subject.
Aged 18 to 64 years, inclusive.
Diagnosis of major depressive disorder lasting between 3 weeks and 18 months confirmed by structured clinical interview.
Hamilton Depression Rating Scale-17 score of 18 or higher at screening and baseline with no more than 25% change.
Hamilton Anxiety Rating Scale score of 15 or higher at screening and baseline.
Insomnia Severity Index score of 10 or higher at screening and baseline.
Female participants must be surgically sterile, menopausal for at least 2 years, or use acceptable birth control if of childbearing potential.
Male participants must use medically acceptable contraception during the study period.
Ability to understand and comply with study requirements and provide written informed consent.
Ability to communicate with study staff and complete patient-reported assessments.
Moderate illness severity with a Clinical Global Impressions-Severity score of 4 or higher at screening and baseline.

You will not qualify if you...

Treatment-resistant major depressive disorder with inadequate response to 2 or more approved medications during the current episode.
Current diagnosis of bipolar disorder, antisocial personality disorder, obsessive compulsive disorder, borderline personality disorder, ADHD, PTSD, or panic attacks.
Current or prior diagnosis of psychotic disorder or major depressive disorder with psychotic features.
Score greater than 4 on the Clinician-Administered Dissociative States Scale at screening.
Active seizure disorder or recent traumatic brain injury with symptoms.
Use of esketamine, ketamine, psychedelic agents, or other experimental depression treatments within the past 12 months.
Use of other experimental agents not for depression within the past 3 months.
Use of FDA-approved antidepressants or certain other psychiatric medications within 14 days before baseline.
Use of cannabis or cannabis-derived products within 14 days before baseline.
Positive test for any drug of abuse.
Treatment with medical devices or digital therapeutics for CNS disorders within 90 days.
History of electroconvulsive therapy or similar brain stimulation treatments within 5 years.
Clinically significant kidney or liver dysfunction.
Abnormal heart rate or blood pressure readings at screening.
Evidence of alcohol abuse or positive alcohol screening.
Substance use disorder within the past 12 months.
Use of nicotine products discontinued at least 14 days before randomization.
Use of barbiturates unless stable dose for 3 months.
HIV, COVID-19, active hepatitis B or C, syphilis, or other infectious diseases at screening.
Laboratory evidence of hypothyroidism or unstable diabetes.
Pregnancy, nursing, or planning pregnancy during the study.
Night shift work during the study period.
Recent malignancy except certain skin or cervical cancers.
Recent psychotherapy changes within 4 weeks before screening.
Use of prohibited medications or herbal therapies that may affect psychiatric assessments.
History of allergy or intolerance to zelquistinel or related drugs.
Previous participation in this study or related studies.
Body mass index over 40 kg/m2.
Employment or family relation to study staff or sponsor.
Significant risk of suicidal behavior or recent suicidal attempts.
Investigator or sponsor judgment deeming participant inappropriate for the study.

Research Team

Karen Raudibaugh

Sharon Ortiz

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Phase 2 Study on the Safety and Effectiveness of Zelquistinel Compared to Placebo for Treating Major Depressive Disorder in Adults Aged 18 to 64

On this page

AI-Summary

What this Trial Is About

Brief Title

Who Can Participate

Eligibility Criteria

Research Team

Not the Right Trial for You?

On this page

Who Can Participate

Eligibility Criteria