A Study to Evaluate TNX-102 SL Monotherapy Versus Placebo in Participants With Major Depressive Disorder (MDD) (HORIZON)

June 1, 2026 updated by: Tonix Pharmaceuticals, Inc.

A Phase 2, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study to Evaluate the Efficacy, Safety, and Tolerability of TNX-102 SL Monotherapy Versus Placebo in Participants With Major Depressive Disorder (MDD)

The goal of this clinical trial is to learn if a drug called TNX-102 SL works to treat moderate to severe major depressive disorder in adults. It will also learn about the safety of TNX-102 SL. The main questions it aims to answer are:

Does TNX-102 SL improve depression symptoms according to a depression symptom rating scale? What medical problems do participants have when taking TNX-102 SL?

Researchers will compare TNX-102 SL to a placebo (a look-alike substance that contains no drug) to see if TNX-102 SL works to treat major depressive disorder.

Participants will:

Take TNX-102 SL or a placebo every night at bedtime for 6 weeks Visit the clinic once every 2 weeks for checkups and tests

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

360

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Arizona
      • Phoenix, Arizona, United States, 85012
        • Not yet recruiting
        • IMA Clinical Research- Phoenix
    • California
      • Chino, California, United States, 91710
        • Not yet recruiting
        • Inland Psychiatric Medical Group, Inc. - Chino
      • Lemon Grove, California, United States, 91945
        • Not yet recruiting
        • Synergy Research - San Diego
      • Orange, California, United States, 92868
        • Not yet recruiting
        • Nrc Research Institute
      • San Diego, California, United States, 92123
        • Not yet recruiting
        • Artemis Institute For Clinical Research - San Diego
      • Walnut Creek, California, United States, 94596
        • Not yet recruiting
        • Sunwise Clinical Research, Llc
    • Florida
      • Jacksonville, Florida, United States, 32256
        • Not yet recruiting
        • Clinical Neuroscience Solutions Inc. - Jacksonville
      • Maitland, Florida, United States, 32751
        • Not yet recruiting
        • K2 Medical Research - Maitland
      • Miami, Florida, United States, 33125
        • Not yet recruiting
        • Central Miami Medical Institute Llc.
      • Orange City, Florida, United States, 32763
        • Not yet recruiting
        • Medical Research Group of Central Florida
      • Orlando, Florida, United States, 32801
        • Recruiting
        • Clinical Neuroscience Solutions Inc. - Orlando
      • Tampa, Florida, United States, 33634
        • Not yet recruiting
        • K2 Medical Research - Tampa
    • Georgia
      • Norcross, Georgia, United States, 30092
        • Not yet recruiting
        • Evergreen Clinical Trials
    • Illinois
      • Chicago, Illinois, United States, 60634
        • Not yet recruiting
        • Chicago Research Center
    • Louisiana
      • New Orleans, Louisiana, United States, 70115
        • Recruiting
        • Delricht Research - New Orleans
    • Maryland
      • Rockville, Maryland, United States, 20852
        • Not yet recruiting
        • Delricht Research - Rockville
    • Massachusetts
      • Methuen, Massachusetts, United States, 01844
        • Not yet recruiting
        • Activmed Practices & Research, Llc - Methuen
    • Nevada
      • Las Vegas, Nevada, United States, 89119
        • Not yet recruiting
        • Redbird Research
    • New York
      • New York, New York, United States, 10036
        • Not yet recruiting
        • Ima Clinical Research - Nyc Midtown
    • South Carolina
      • North Charleston, South Carolina, United States, 29405
        • Not yet recruiting
        • Coastal Carolina Research Center
    • Tennessee
      • Mephis, Tennessee, United States, 38119
        • Not yet recruiting
        • Clinical Neuroscience Solutions Inc. - Memphis
    • Texas
      • Austin, Texas, United States, 78737
        • Not yet recruiting
        • Austin Clinical Trial Partners
      • McKinney, Texas, United States, 75071
        • Not yet recruiting
        • Revival Research Institute, Llc - McKinney, Tx
      • Plano, Texas, United States, 75024
        • Not yet recruiting
        • Delricht Research - Plano
    • Utah
      • Provo, Utah, United States, 84604
        • Not yet recruiting
        • Boeson Research Pvu

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Primary DSM-5 diagnosis of current MDD.
  • The duration of the current MDE must be between 6 weeks and 18 months.
  • Without psychotic or catatonic features.
  • Capable of reading and understanding English and able to provide written informed consent to participate.

Exclusion Criteria:

  • Diagnosis of DSM-5-defined lifetime bipolar disorder (I, II, or unspecified), schizophrenia, schizoaffective disorder, MDD with psychotic features, other psychotic disorder, or antisocial personality disorder; current (past month) obsessive-compulsive disorder; current (past month) posttraumatic stress disorder; current (past 3 months) anorexia nervosa,
  • Diagnosis of borderline personality disorder that is known, suspected
  • Participants with comorbid generalized anxiety disorder (GAD), social anxiety disorder (SAD), or panic disorder are excluded only if the GAD, SAD, or panic disorder is considered the primary psychiatric diagnosis, rather than MDD.
  • Participants with treatment refractory MDD, ie, previously having failed in their lifetime ≥2 treatments (due to inadequate efficacy) with at least 2 different classes of antidepressants of adequate dose, duration, and treatment adherence.
  • History of substance use disorder and/or alcohol use disorder during the preceding 12 months
  • Use of antidepressants (including ketamine/esketamine, St. John's Wort, S-adenosyl methionine, and/or trazodone used as an antidepressant) within 4 weeks of Baseline (Visit 2), except for fluoxetine, which must not be within 6 weeks of Baseline (Visit 2)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: TNX-102 SL
Participants will take 5.6 mg of TNX-102 SL ( 2 x 2.8 mg TNX-102 SL tablets) daily at bedtime.
Drug: TNX-102 SL
Participants will take 5.6 mg of TNX-102 SL ( 2 x 2.8 mg TNX-102 SL tablets) daily at bedtime.
Other Names:
  • cyclobenzaprine HCl
  • cyclobenzaprine
Placebo Comparator: Placebo sublingual tablets
Participants will take placebo ( 2 x placebo sublingual tablets) daily at bedtime.
Drug: Placebo sublingual tablet
Participants will take placebo ( 2 x placebo sublingual tablets) daily at bedtime.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change from Baseline (Visit 2) in the MADRS total score at Week 6.
Time Frame: From Day 1 to Week 6
Change from Baseline (Visit 2) in the MADRS total score at Week 6. Scores range from 0 to 60. Lower scores indicate less depression.
From Day 1 to Week 6

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change from Baseline (Visit 2) in the Clinician Global Impression - Severity (CGI-S) score at Week 6
Time Frame: From Day 1 to Week 6
Change from Baseline (Visit 2) in the Clinical Global Impression of Severity Scale (CGI-S) score at Week 6. Scores range from 1 to 5. Lower scores indicate less severe illness.
From Day 1 to Week 6
Change from Baseline (Visit 2) in the PROMIS Sleep Disturbance T-score at Week 6
Time Frame: From Day 1 to Week 6
Change from Baseline (Visit 2) in the PROMIS Sleep Disturbance T-score at Week 6. The Patient-Reported Outcome Measurement Information System (PROMIS) sleep disturbance instrument consists of 8 items in which responses are scored 1 to 5 for each item. PROMIS scores are presented as T-scores in which the raw score has been rescaled into a standardized score with a mean of 50 and a standard deviation of 10. Higher T-scores represent more of the concept being measured (in this case, sleep disturbance).
From Day 1 to Week 6
Change from Baseline (Visit 2) in the MADRS total score at Week 4.
Time Frame: From Day 1 to Week 4
Change from Baseline (Visit 2) in the MADRS total score at Week 4. Scores range from 0 to 60. Lower scores indicate less depression.
From Day 1 to Week 4
Change from Baseline (Visit 2) in the MADRS total score at Week 2.
Time Frame: From Day 1 to Week 2
Change from Baseline (Visit 2) in the MADRS total score at Week 2. Scores range from 0 to 60. Lower scores indicate less depression.
From Day 1 to Week 2

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Tonix Pharmaceuticals, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

February 1, 2028

Study Completion (Estimated)

February 1, 2028

Study Registration Dates

First Submitted

May 27, 2026

First Submitted That Met QC Criteria

June 1, 2026

First Posted (Actual)

June 2, 2026

Study Record Updates

Last Update Posted (Actual)

June 2, 2026

Last Update Submitted That Met QC Criteria

June 1, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • TNX-CY-MD201

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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