A Study of CLE-100 (Oral Esketamine) as an Adjunctive Treatment to Standard Antidepressants for Major Depressive Disorder (SOLEO)

May 27, 2026 updated by: Clexio Biosciences Ltd.

A Randomized, Double-Blind, Placebo-Controlled, Multicenter, Parallel-Design, Phase 2 Study to Assess the Efficacy and Safety of CLE-100 as an Adjunctive Treatment for Major Depressive Disorder Patients With Inadequate Response to Standard Antidepressants

The study is a Phase 2, double-blind, randomized, placebo-controlled study in Major Depressive Disorder (MDD) participants with an inadequate response to standard antidepressants The objective of the study is to assess CLE-100 (oral esketamine) for the treatment of MDD in participants currently treated with an oral antidepressant medication and who have an inadequate response to at least 2 antidepressants.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is a Phase 2 study in subjects with MDD currently treated with an oral antidepressant medication with an inadequate response to at least 2 antidepressants. SOLEO will be an outpatient study to assess the safety, efficacy, and tolerability of CLE-100 as compared to placebo.

Eligible subjects will be randomized to receive either placebo or CLE-100 (oral esketamine) once daily in addition to their current oral antidepressant monotherapy for 4 weeks. All subjects who adequately completed the 4-week Double-Blind Treatment Period and who meet the eligibility criteria will be offered the option to roll-over to a 6-month Open-label Extension (OLE) Treatment Period with CLE-100.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
99

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

  • Name: Patient Information Page https://osmind.info/DBSA

Study Locations

  • United States
    • California
      • La Jolla, California, United States, 92037
        • Clinical Site 139
      • Lafayette, California, United States, 94549
        • Clinical Site 131
      • Upland, California, United States, 91786
        • Clinical Site 130
    • Florida
      • Hollywood, Florida, United States, 33024
        • Clinical Site 102
      • Lauderhill, Florida, United States, 33319
        • Clinical Site 105
      • Miami Springs, Florida, United States, 33166
        • Clinical Site 140
      • Pensacola, Florida, United States, 32502
        • Clinical Site 132
    • Georgia
      • Atlanta, Georgia, United States, 30030
        • Clinical Site 118
      • Marietta, Georgia, United States, 30060
        • Clinical Site 138
      • Savannah, Georgia, United States, 31405
        • Clinical Site 114
    • Illinois
      • Chicago, Illinois, United States, 60640
        • Clinical Site 127
      • Elgin, Illinois, United States, 60123
        • Clinical Site 120
    • Maryland
      • Gaithersburg, Maryland, United States, 20877
        • Clinical Site 108
    • Mississippi
      • Flowood, Mississippi, United States, 39232
        • Clinical Site 116
    • Missouri
      • O'Fallon, Missouri, United States, 63368
        • Clinical Site 126
    • New Jersey
      • Toms River, New Jersey, United States, 08755
        • Clinical Site 101
    • Ohio
      • Beachwood, Ohio, United States, 44236
        • Clinical Site 103
      • North Canton, Ohio, United States, 44720
        • Clinical Site 119
    • Oklahoma
      • Oklahoma City, Oklahoma, United States, 73112
        • Clinical Site 135
    • Texas
      • Austin, Texas, United States, 78737
        • Clinical Site 107
      • Plano, Texas, United States, 75093
        • Clinical Site 137
    • Utah
      • Murray, Utah, United States, 84107
        • Clinical Site 117
    • Washington
      • Bellevue, Washington, United States, 98007
        • Clinical Site 115

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Male or female between 18 to 65 years of age at Screening
  2. Diagnosis of MDD, single or recurrent, without psychotic features, in the current or previous episode(s), according to the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5). The diagnosis of MDD must be supported by the Mini International Neuropsychiatric Interview (MINI) Screen 7.0.2 for DSM-5.
  3. Currently experiencing a Major Depressive Episode (MDE) that began at least 12 weeks but no more than 5 years prior to Screening. The current MDE must be confirmed by the independent SAFER assessor.
  4. MADRS score of 24 or higher at Screening as confirmed by an independent SAFER assessor.
  5. At Screening, a history of inadequate response to at least 2 antidepressant medications in the current MDE. Inadequate response is defined as less than 50% improvement of depression symptoms following at least 6 weeks of treatment with a therapeutic dose and is assessed by the site using the Massachusetts General Hospital Antidepressant Treatment Response Questionnaire (MGH-ATRQ). Inadequate response to at least 2 antidepressant medications must be verified by documented medical or pharmacy records and confirmed by an independent SAFER assessor.
  6. Able and competent to read and sign the informed consent form (ICF).

Exclusion Criteria:

  1. At Screening, a history of inadequate response (as defined in inclusion criterion #5) to more than 5 antidepressant medications in the current MDE using MGH-ATRQ and confirmed by the independent SAFER assessor.

  2. A high risk of suicide based on any of the following:

    1. Item 10 of MADRS score (suicidal thoughts) is 5 or higher at Screening or Baseline.
    2. Suicide attempt in the previous 6 months.
    3. Significant risk, as judged by the Investigator, based on the psychiatric interview or information collected with the C SSRS at Screening or Baseline.
  3. Current or lifetime history of substance use disorder with ketamine, phencyclidine (PCP), lysergic acid diethylamide (LSD), or 3.4-methylenedioxymethamphetamine (MDMA) hallucinogen-related use disorders or has any other current substance use disorder or history within 12 months prior to Screening (Substance Use Disorder is diagnosed per DSM-5 criteria and does not include tobacco use disorder).
  4. Use of ketamine, esketamine, PCP, or dextromethorphan recreationally in the past 6 months.
  5. History or current diagnosis of bipolar disorder, schizophrenia, or schizoaffective disorder or other schizophrenia spectrum disorders.
  6. Dementia, delirium, amnesia, or any other significant cognitive disorder.
  7. Any medical condition for which an increase in blood pressure or intracranial pressure or intraocular pressure or tachycardia poses a serious risk (e.g., aneurysmal vascular disease, arteriovenous malformation, or history of intracerebral hemorrhage).

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: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: CLE-100
1 oral tablet of CLE-100 once daily (in addition to current anti-depressant drug) for 4 weeks
Drug: CLE-100
1 tablet of CLE-100 administered once daily
Placebo Comparator: Placebo
1 oral tablet of Placebo once daily (in addition to current anti-depressant drug) for 4 weeks.
Drug: Placebo
1 tablet of placebo administered once daily

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change From Baseline in Montgomery-Asberg Depression Rating Scale (MADRS) Score
Time Frame: 29 days
The MADRS is a validated clinician-administered measurement of depression severity commonly used in clinical trials of depression treatments to select subjects and assess efficacy. The test consists of 10 items, each of which is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score of 60. Higher scores represent a more severe condition.
29 days

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change From Baseline in the Clinical Global Impression - Severity (CGI-S)
Time Frame: 29 days
The CGI-S is a well-known and frequently used clinician-administered instrument for the assessment of MDD that weighs the clinical impact of the identified symptom(s) on behavior and function. The CGI-S grades measures of psychopathology on a scale from 1 to 7.
29 days
Change From Baseline in Montgomery-Asberg Depression Rating Scale (MADRS) Score
Time Frame: 2 weeks
The MADRS is a validated clinician-administered measurement of depression severity commonly used in clinical trials of depression treatments to select subjects and assess efficacy. The test consists of 10 items, each of which is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score of 60. Higher scores represent a more severe condition.
2 weeks
Safety Outcomes: Assessment of the Safety and Tolerability of CLE-100 Compared to Placebo
Time Frame: Through study completion, an average of 7 months

Assessment of the safety and tolerability of CLE-100 compared to placebo using the following assessments:

  • Adverse Events (AEs)
  • Adverse events of special interest (AESIs)
  • Clinical laboratory evaluations
  • Vital signs
  • 12-lead electrocardiogram
  • Modified Observer's Assessment of Alertness/Sedation scale (MOAA/S)
  • Clinician-Administered Dissociative State Scale (CADSS)
  • Incidence of suicidal ideation or behavior as assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS)
  • 4-item Brief Psychiatric Rating Scale (BPRS)
  • 20-item Physician Withdrawal Checklist (PWC-20)
  • Bladder Pain/Interstitial Cystitis Symptom Score (BPIC-SS)
  • Digit Symbol Substitution Test (DSST)
  • Discontinuation rates and reason(s) for discontinuation
Through study completion, an average of 7 months

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Clexio Biosciences Ltd.

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 18, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 6, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 25, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 25, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 1, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 2, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 23, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CLE100-MDD-202

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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