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Depressive Disorder, MajorPhase 2AGN-241751NCT03586427

Zelquistinel in the Treatment of Major Depressive Disorder

A Phase 2 study testing AGN-241751 in people with Depressive Disorder, Major, run by Syndeio Biosciences, Inc at 25 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
Search all trials

Trial summary

The purpose of this study is to evaluate the efficacy at 1 day post initial oral dose of zelquistinel (AGN-241751) compared with placebo in participants with Major Depressive Disorder (MDD). Read more about this study

Who is it for?
Ages 18 to 65 years
Conditions the study is for
Depressive Disorder, Major
What is being tested?
AGN-241751
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
251 participants
Where
25 sitesUnited States
Study dates
13 Jun 2018to 21 Aug 2019
Phase
Phase 2
Are there results?
Yes, posted in the registrySummary in the doctors' view

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 65 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Written informed consent from the participant has been obtained prior to any study -related procedures (as described in Appendix 3).
  • Male or female participants must be 18 to 65 years of age, inclusive, at the time of signing the informed consent.
  • Meet Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) criteria for MDD (based on confirmation from the modified Structured Clinical Interview for DSM disorders [SCID]), with a current major depressive episode of at least 8 weeks and not exceeding 18 months in duration at Visit 1.
  • Have a minimum score of 26 on the rater-administered Montgomery-Asberg depression rating scale (MADRS) and a minimum score of 24 on the computer-administered MADRS at both Visit 1 (Screening) and Visit 2 (Baseline).
  • Have a difference of no greater than 7 points between the rater-administered MADRS and computer-administered MADRS at both Visit 1 (Screening) and Visit 2 (Baseline).
  • Have a clinical global impression-severity (CGI-S) score ≥ 4 at both Visit 1 (Screening) and Visit 2 (Baseline).
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  • Have a negative serum β-human chorionic gonadotropin (β-hCG) pregnancy test if a woman of childbearing potential (WOCBP).
  • Female participants willing to minimize the risk of becoming pregnancy for the duration of the clinical study and follow-up period. A female participant is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies:
  • not a WOCBP OR
  • A WOCBP who agrees to follow the contraceptive guidance in Appendix 5 of protocol during the treatment period and for at least 5 terminal half-lives after the last dose of study treatment.
  • Male participants willing to minimize the risk of inducing pregnancy for the duration of the clinical study and follow-up period. A male participant must agree to use contraception as detailed in Appendix 5 of this protocol during the treatment period and for at least 5 terminal half-lives after the last dose of study treatment and refrain from donating sperm during this period.
  • Able, as assessed by the investigator, and willing to follow study instructions and likely to complete all required study visits.
  • Normal physical-examination findings, clinical-laboratory test results, and electrocardiogram (ECG) results from Visit 1 (Screening) or abnormal results that are determined to be not clinically significant by the investigator.
  • Body mass index (BMI) within the range 18 and 40 kg/m^2 (inclusive).
  • Eligibility confirmed through a formal adjudication process (see Section 9 Diagnostic Assessments).

Who cannot join

  • Psychiatric and Treatment-Related Criteria
  • DSM-5-based diagnosis of any disorder other than MDD that was the primary focus of treatment within 6 months before Visit 1. Comorbid generalized anxiety disorder, social anxiety disorder, or specific phobias are acceptable provided they play a secondary role in the balance of symptoms and are not the primary driver of treatment decisions.
  • Lifetime history of meeting DSM-5 criteria for:
  • Schizophrenia spectrum or other psychotic disorder
  • Bipolar or related disorder
  • Major neurocognitive disorder
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  • Neurodevelopmental disorder of greater than mild severity or of a severity that impacts the participant's ability to consent, follow study directions, or otherwise safely participate in the study
  • Dissociative disorder
  • Posttraumatic stress disorder
  • MDD with psychotic features
  • History of meeting DSM-5 criteria for alcohol or substance use disorder (other than nicotine or caffeine) within the 6 months before Visit 1.
  • DSM-5-based diagnosis of any personality disorder of sufficient severity to interfere with participation in this study in the opinion of the investigator.
  • History (based on participant report and/or medical records, and investigator judgment) of:
  • Inadequate response to electroconvulsive therapy (ECT), a monoamine oxidase inhibitor, ketamine, or adjunctive treatment with an antipsychotic
  • Treatment with clozapine or any depot antipsychotic
  • ECT, vagus nerve stimulation, transcranial magnetic stimulation, or any experimental central nervous system treatment during the current episode or in the 6 months before Visit 1 (whichever is longer)
  • Tardive dyskinesia, serotonin syndrome, or neuroleptic malignant syndrome
  • Having received:
  • Anticonvulsant/mood stabilizer, within 1 year prior to Visit 1
  • Antipsychotic in the current episode, with the exception of quetiapine given for insomnia ≤ 50 mg/day provided it can be safely discontinued prior to Visit 2
  • Combination therapy of 2 or more antidepressant therapies (ADTs) in the current episode if given for depression at adequate dose and duration
  • ADT augmentation agent in the current episode
  • Lifetime history of nonresponse to ≥ 2 antidepressants after adequate trials (adequate treatment is defined as at least 6 weeks at an adequate dose(s) based on approved package insert recommendations) or a non-response to an antidepressant after adequate treatment for the current major depressive episode.
  • Positive result at Visit 1 from the urine drug screen (UDS) test for any prohibited medication. Exception: participants with a positive UDS at Visit 1 for opiates, cannabinoids, or episodic use of benzodiazepines may be allowed in the study provided:
  • The drug was used for a legitimate medical purpose;
  • The drug can be discontinued prior to participation in the study (except for episodic use of benzodiazepines which may be continued); and
  • A repeat UDS is negative for these substances prior to enrollment (except for episodic use of benzodiazepines which may be continued)
  • Suicide risk, as determined by meeting any of the following criteria:
  • A suicide attempt within the past year
  • Significant risk, as judged by the investigator, based on the psychiatric interview or information collected in the C-SSRS at Visit 1 (Screening) or Visit 2 (Baseline)
  • MADRS Item 10 score ≥ 5 at Visit 1 (Screening) or Visit 2 (Baseline) on the MADRS
  • At imminent risk of injuring self or others or causing significant damage to property, as judged by the investigator.
  • Requiring concomitant treatment with any of the prohibited medications, supplements, or herbal products listed in Appendix 6 of protocol, including any psychotropic drug or any drug with psychotropic activity, except as described in Section 7.7.2. of protocol.
  • Prior participation in any investigational study of AGN-241751.
  • Initiation or termination of psychotherapy for depression within the 3 months preceding Visit 1, or plans to initiate, terminate, or change such therapy during the course of the study. (Support meetings or counselling [eg, marital counselling] are allowed provided they are no more frequent than weekly and do not have treatment of depression as their objective).
  • Ongoing treatment with phototherapy, or termination of phototherapy within 1 month of Visit 1.
  • Known allergy or sensitivity to the study medication or its components.
  • Other Medical Criteria
  • BMI < 18 kg/m^2 or > 40 kg/m^2 at screening.
  • Females who are pregnant, breastfeeding, or planning to become pregnant or breastfeed during the study.
  • WOCBP and male partners of WOCBP, not using a reliable means of contraception (Appendix 5 of protocol).
  • Participant has a condition or is in a situation which, in the investigator's opinion, may put the participant at significant risk, may confound the study results, or may interfere significantly with the participant's participation in the study.
  • Any cardiovascular disease that is clinically significant, unstable, or decompensated.
  • Heart rate (supine) of ≤ 45 beats per minute (bpm) or ≥ 120 bpm, or any heart rate that is clinically symptomatic at Visit 1 or Visit 2 based upon vital signs.
  • Any systolic and/or diastolic blood pressure (BP) that is symptomatic or clinically significant in the opinion of the investigator.
  • History of congenital QTc prolongation or QTc prolongation (screening ECG with QTcF ≥ 450 msec for men and QTcF ≥ 470 msec for women).
  • Hypothyroidism or hyperthyroidism, unless stabilized on appropriate pharmacotherapy with no change in dosage for at least 1 month before Visit 1.
  • History of seizure disorder, stroke, significant head injury, tumor of the central nervous system, or any other condition that predisposes to seizure.
  • Known human immunodeficiency virus (HIV) infection.
  • Positive hepatitis C antibody on screening, with the exception of participants for whom the reflex hepatitis C virus ribonucleic acid (HCV RNA) test is negative.
  • Positive test for hepatitis B surface antigen and/or hepatitis B core antibody immunoglobulin M.
  • Screening liver enzyme test (aspartate aminotransferase [AST] and/or alanine aminotransferase [ALT]) results > 2 times the upper limit of normal (ULN).
  • Other Criteria
  • Current enrollment in an investigational drug or device study or participation in such a study within 6 months of entry into this study.
  • Employee, or immediate relative of an employee, of the sponsor, any of its affiliates or partners, or the study center.
  • Inability to speak, read, and understand the English language sufficiently to understand the nature of the study, to provide written informed consent, or to allow the completion of all study assessments.

Trial locations and contacts

25 sites in 1 country.

25 sites in 1 country

United States25 sites

  • Synexus US - Atlanta

    Atlanta, Georgia, 30328

  • Atlanta Center for Medical Research

    Atlanta, Georgia, 30331

  • Donald J. Garcia, Jr., MD, PA

    Austin, Texas, 78737

  • Northwest Clinical Research Center

    Bellevue, Washington, 98007

  • Hassman Research Institute

    Berlin, New Jersey, 08009

  • Boston Clinical Trials

    Boston, Massachusetts, 02131

  • Neurobehavioral Research, Inc

    Cedarhurst, New York, 11516

  • Synexus US - Cerritos

    Cerritos, California, 90703

  • Center for Emotional Fitness

    Cherry Hill, New Jersey, 08002

  • FutureSearch Trials of Dallas, LP

    Dallas, Texas, 75231

  • Wake Research - Pharmacology Research Institute

    Encino, California, 91316

  • Health Initiatives Research PLLC

    Fayetteville, Arkansas, 72703

  • Synexus US - Queens

    Jamaica, New York, 11432

  • Pillar Clinical Research

    Lincolnwood, Illinois, 60712

  • Clinical Neuroscience Solutions, Inc - Memphis, TN

    Memphis, Tennessee, 38119

  • Research Strategies of Memphis, LLC

    Memphis, Tennessee, 38119

  • Eastside Comprehensive Medical Center

    New York, New York, 10128

  • Wake Research - Pharmacology Research Institute

    Newport Beach, California, 92660

  • Neuro-Behavioral Clinical Research, Inc

    North Canton, Ohio, 44720

  • Pacific Research Partners, LLC

    Oakland, California, 94607

  • North County Clinical Research, Inc.

    Oceanside, California, 92054

  • IPS Research

    Oklahoma City, Oklahoma, 73106

  • Finger Lakes Clinical Research

    Rochester, New York, 14618

  • Collaborative Neuroscience Network

    Torrance, California, 90502

  • Elite Clinical Trials, Inc.

    Wildomar, California, 92595

Other trials in United States

About this study

Official title: A Double-Blind, Placebo-Controlled, Fixed-Dose Study of AGN-241751 in Adult Participants With Major Depressive Disorder

The purpose of this study is to evaluate the efficacy at 1 day post initial oral dose of zelquistinel (AGN-241751) compared with placebo in participants with Major Depressive Disorder (MDD).

Being tested
AGN-241751, Placebo
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.

  • AGN-241751Drug

    AGN-241751 administered orally as a single tablet

  • PlaceboDrug

    Placebo administered orally as a single tablet

Study groups in NCT03586427
Study groupRoleWhat they receive
AGN-241751 Dose 1ExperimentalAGN-241751 Dose 1 administered as 1 tablet taken orally every day
Receives: Drug: AGN-241751
AGN-241751 Dose 2ExperimentalAGN-241751 Dose 2 administered as 1 tablet taken orally every day
Receives: Drug: AGN-241751
AGN-241751 Dose 3ExperimentalAGN-241751 Dose 3 administered as 1 tablet taken orally every day
Receives: Drug: AGN-241751
AGN-241751 Dose 4ExperimentalAGN-241751 Dose 4 administered as 1 tablet taken orally every day
Receives: Drug: AGN-241751
PlaceboPlacebo comparatorPlacebo administered as 1 tablet taken orally every day
Receives: Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change From Baseline in Montgomery-Asberg Depression Rating Scale (MADRS) Total Score

    The MADRS is a clinician-rated scale to assess depressive symptomatology during the preceding week. Participants are rated on 10 items (feelings of sadness, lassitude, pessimism, inner tension, suicidality, reduced sleep or appetite, difficulty concentrating, and lack of interest) each on a 7-point scale from 0 (no symptoms) to 6 (symptoms of maximum severity). The total score ranges from 0 to 60 with a higher score indicating more depression. A negative change score indicates improvement.

    Measured: Baseline to Day 1

Secondary outcomes (1)

  1. Change From Baseline in MADRS Total Score at Week 3

    The MADRS is a clinician-rated scale to assess depressive symptomatology during the preceding week. Participants are rated on 10 items (feelings of sadness, lassitude, pessimism, inner tension, suicidality, reduced sleep or appetite, difficulty concentrating, and lack of interest) each on a 7-point scale from 0 (no symptoms) to 6 (symptoms of maximum severity). The total score ranges from 0 to 60 with a higher score indicating more depression. A negative change score indicates improvement.

    Measured: Baseline to Week 3

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted13 Jul 2018
  2. Study start13 Jun 2018
  3. Primary completion22 Jul 2019
  4. Study completion21 Aug 2019

Resources

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
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
251 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03586427
Sponsor's protocol ID
3125-201-002
Acronym
AGN-241751
Status last verified
Apr 2026
First submitted
22 Jun 2018
Last updated
27 Apr 2026
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No: This is a phase 2 dose finding proof of concept study therefore data will not be shared.

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing AGN-241751 in people with Depressive Disorder, Major, run by Syndeio Biosciences, Inc at 25 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 15 inclusion and 56 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: finished, as of the sponsor's last update on 27 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 25 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?

Yes. Results are posted in the registry (first posted 2 Aug 2022). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change From Baseline in Montgomery-Asberg Depression Rating Scale (MADRS) Total Score (time frame: Baseline to Day 1). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03586427.

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 Apr 2026.

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