Adjunctive Treatment of Major Depressive Disorder (MDD)Phase 2SOLEONCT06340958
A Study of CLE-100 (Oral Esketamine) as an Adjunctive Treatment to Standard Antidepressants for Major Depressive Disorder
A Phase 2 study testing CLE-100 in people with Adjunctive Treatment of Major Depressive Disorder (MDD), run by Clexio Biosciences Ltd. at 23 sites in United States.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Adjunctive Treatment of Major Depressive Disorder (MDD)
- What is being tested?
- CLE-100
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 99 participants
- Where
- 23 sitesUnited States
- Study dates
- 18 Mar 2024to 25 Nov 2025
- 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
- Male or female between 18 to 65 years of age at Screening
- 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.
- 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.
- MADRS score of 24 or higher at Screening as confirmed by an independent SAFER assessor.
- 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.
- Able and competent to read and sign the informed consent form (ICF).
Who cannot join
- 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.
- A high risk of suicide based on any of the following:
- Item 10 of MADRS score (suicidal thoughts) is 5 or higher at Screening or Baseline.
- Suicide attempt in the previous 6 months.
- Significant risk, as judged by the Investigator, based on the psychiatric interview or information collected with the C SSRS at Screening or Baseline.
- 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).
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- Use of ketamine, esketamine, PCP, or dextromethorphan recreationally in the past 6 months.
- History or current diagnosis of bipolar disorder, schizophrenia, or schizoaffective disorder or other schizophrenia spectrum disorders.
- Dementia, delirium, amnesia, or any other significant cognitive disorder.
- 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).
Trial locations and contacts
23 sites in 1 country.
23 sites in 1 country
United States23 sites
Clinical Site 118
Atlanta, Georgia, 30030
Clinical Site 107
Austin, Texas, 78737
Clinical Site 103
Beachwood, Ohio, 44236
Clinical Site 115
Bellevue, Washington, 98007
Clinical Site 127
Chicago, Illinois, 60640
Clinical Site 120
Elgin, Illinois, 60123
Clinical Site 116
Flowood, Mississippi, 39232
Clinical Site 108
Gaithersburg, Maryland, 20877
Clinical Site 102
Hollywood, Florida, 33024
Clinical Site 139
La Jolla, California, 92037
Clinical Site 131
Lafayette, California, 94549
Clinical Site 105
Lauderhill, Florida, 33319
Clinical Site 138
Marietta, Georgia, 30060
Clinical Site 140
Miami Springs, Florida, 33166
Clinical Site 117
Murray, Utah, 84107
Clinical Site 119
North Canton, Ohio, 44720
Clinical Site 126
O'Fallon, Missouri, 63368
Clinical Site 135
Oklahoma City, Oklahoma, 73112
Clinical Site 132
Pensacola, Florida, 32502
Clinical Site 137
Plano, Texas, 75093
Clinical Site 114
Savannah, Georgia, 31405
Clinical Site 101
Toms River, New Jersey, 08755
Clinical Site 130
Upland, California, 91786
About this study
Official title: 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.
Read the 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.
- Being tested
- CLE-100, Placebo
- Keywords
- MDD, inadequate response, depression, depressive disorder, major depression, adjunct therapy, oral, esketamine
- Medical subject headings
- Depression, Depressive Disorder, Depressive Disorder, Major
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CLE-100Drug
1 tablet of CLE-100 administered once daily
PlaceboDrug
1 tablet of placebo administered once daily
| Study group | Role | What they receive |
|---|---|---|
| CLE-100 | Experimental | 1 oral tablet of CLE-100 once daily (in addition to current anti-depressant drug) for 4 weeks Receives: Drug: CLE-100 |
| Placebo | Placebo comparator | 1 oral tablet of Placebo once daily (in addition to current anti-depressant drug) for 4 weeks. Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change From Baseline in Montgomery-Asberg Depression Rating Scale (MADRS) Score
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.
Measured: 29 days
Secondary outcomes (3)
Change From Baseline in the Clinical Global Impression - Severity (CGI-S)
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.
Measured: 29 days
Change From Baseline in Montgomery-Asberg Depression Rating Scale (MADRS) Score
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.
Measured: 2 weeks
Safety Outcomes: Assessment of the Safety and Tolerability of CLE-100 Compared to Placebo
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
Measured: Through study completion, an average of 7 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Apr 2024
- Study start18 Mar 2024
- Primary completion6 Jun 2025
- Study completion25 Nov 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Adjunctive Treatment of Major Depressive Disorder (MDD)Studies 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
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 99 participants (actual)
Sponsor and investigators
- Lead sponsor
- Clexio Biosciences Ltd.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06340958
- Sponsor's protocol ID
- CLE100-MDD-202
- Acronym
- SOLEO
- Status last verified
- May 2026
- First submitted
- 25 Mar 2024
- Last updated
- 23 Jun 2026
- Results posted
- Yes, on ClinicalTrials.gov
- 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 23 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT06340958
- Acronym / sponsor ID
- SOLEO / CLE100-MDD-202
- Keywords
- MDD, inadequate response, depression, depressive disorder, major depression, adjunct therapy, oral, esketamine
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 99 participants (actual)
- Lead sponsor
- Clexio Biosciences Ltd.Industry (pharma, biotech, devices)
- Study start
- 18 Mar 2024 (actual)
- Primary completion
- 6 Jun 2025 (actual)
- Study completion
- 25 Nov 2025 (actual)
- First posted
- 2 Apr 2024 (actual)
- Results
- Posted 23 Jun 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| CLE-100 | Experimental | Drug: CLE-1001 oral tablet of CLE-100 once daily (in addition to current anti-depressant drug) for 4 weeks |
| Placebo | Placebo comparator | Drug: Placebo1 oral tablet of Placebo once daily (in addition to current anti-depressant drug) for 4 weeks. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Male or female between 18 to 65 years of age at Screening
- 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.
- 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.
- MADRS score of 24 or higher at Screening as confirmed by an independent SAFER assessor.
- 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.
Key exclusion criteria (10 listed)
- 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.
- A high risk of suicide based on any of the following:
- 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).
- Use of ketamine, esketamine, PCP, or dextromethorphan recreationally in the past 6 months.
- History or current diagnosis of bipolar disorder, schizophrenia, or schizoaffective disorder or other schizophrenia spectrum disorders.
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 |
|---|---|---|
| CLE-1001 tablet of CLE-100 administered once daily | Drug | CLE-100 |
| Placebo1 tablet of placebo administered once daily | Drug | Placebo |
Primary outcome
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.
3 secondary outcomes
Change From Baseline in the Clinical Global Impression - Severity (CGI-S)
Time frame: 29 days
Change From Baseline in Montgomery-Asberg Depression Rating Scale (MADRS) Score
Time frame: 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
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Jun 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- 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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
23 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 CLE-100 in people with Adjunctive Treatment of Major Depressive Disorder (MDD), run by Clexio Biosciences Ltd. at 23 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 6 inclusion and 10 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 23 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 23 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 23 Jun 2026). 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) Score (time frame: 29 days). 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 23 Jun 2026.