Major Depressive DisorderPhase 2NCT05593029
A Trial of the Safety and Efficacy of SEP-363856 in the Treatment of Adults With Major Depressive Disorder
A Phase 2 study testing SEP-363856 in people with Major Depressive Disorder, run by Otsuka Pharmaceutical Development & Commercialization, Inc. at 77 sites in 7 countries.
Trial summary
Demonstrate ability of SEP-363856 to be superior to placebo as an adjunctive therapy to ADT in change from baseline in depressive symptoms (MADRS \& CGI-S) in MDD patients who had an inadequate response to prior ADT therapy. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Major Depressive Disorder
- What is being tested?
- SEP-363856
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 929 participants
- Where
- 77 sitesin 7 countries
- Study dates
- 9 Nov 2022to 13 Nov 2025
- Phase
- Phase 2
- Are there results?
- None posted in the registry
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 and Female subjects between 18-65 years of age, with a primary diagnosis of major depressive disorder and in a current major depressive episode
- Current major depressive episode must be at least 8 weeks and no longer than 2 years in duration
- History of an inadequate response to at least 1 and no more than 3 antidepressant treatments in the current major depressive episode
Who cannot join
- Subjects who report an inadequate response to more than 3 antidepressant treatments in the current episode
- Subjects with a lifetime history of schizophrenia spectrum or other psychotic disorder, bipolar or related disorder, major or mild neurocognitive disorder, 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, borderline or antisocial personality disorder.
- Subjects with a current diagnosis of post-traumatic stress disorder, obsessive compulsive disorder, panic disorder, or eating disorder (including anorexia nervosa or bulimia).
- Sexually active subjects, who could become pregnant, not agreeing to practice 2 sponsor approved methods of birth control or remain abstinent during the trial and for 30 days (females) or 90 days (males) after last dose of study drug.
Trial locations and contacts
77 sites in 7 countries.
77 sites in 7 countries
United States53 sites
Advanced Discovery Research LLC
Atlanta, Georgia, 30318
Donald J. Garcia, Jr., MD, PA
Austin, Texas, 78737
Community Clinical Research, Inc.
Austin, Texas, 78754
Pillar Clinical Research
Bentonville, Arkansas, 72712
University of Alabama at Birmingham
Birmingham, Alabama, 35294
Neurobehavioral Medicine Group
Bloomfield Hills, Michigan, 48302
Copley Clinical
Boston, Massachusetts, 02116
Integrative Clinical Trials
Brooklyn, New York, 11229
Center for Emotional Fitness
Cherry Hill, New Jersey, 08002
MetroMed Clinical Trials
Chicago, Illinois, 60614
Patient Priority Clinical Studies LLC
Cincinnati, Ohio, 45215
The Ohio State University
Columbus, Ohio, 43210
ProScience Research Group
Culver City, California, 90230
FutureSearch Trials of Dallas
Dallas, Texas, 75251
Wr-Pri, Llc
Encino, California, 91316
Core Clinical Research
Everett, Washington, 98201
Precise Research Centers
Flowood, Mississippi, 39232
North Texas Clinical Trials
Fort Worth, Texas, 76104
Cenexel CBH (CBH Health)
Gaithersburg, Maryland, 20877
Collaborative NeuroScience Research , LLC
Garden Grove, California, 92845
Institute of Living Hartford Hospital
Hartford, Connecticut, 06106
DM Clinical Research - Belliare
Houston, Texas, 77081
Basil Clinical
Inwood, New York, 11096
Clinical Neuroscience Solutions Inc.
Jacksonville, Florida, 32256
Alliance Research
Long Beach, California, 90807
K2 Medical Research
Maitland, Florida, 32751
Clinical Neuroscience Solutions Inc.
Memphis, Tennessee, 38119
Central Miami Medical Institute
Miami, Florida, 33125
Psychiatric And Behavioral Solutions, LLC
Millcreek, Utah, 84124
Berman Clinical
New York, New York, 10029
Manhattan Behavioral Medicine PLLC
New York, New York, 10036
The Medical Research Network, LLC
New York, New York, 10128
Sooner Clinical Research
Oklahoma City, Oklahoma, 73116
ATP Clinical Research, Inc.
Orange, California, 92868
Clinical Neuroscience Solutions Inc. dba CNS Healthcare
Orlando, Florida, 32801
Combined Research Orlando Phase I-IV
Orlando, Florida, 32807
Anderson Clinical Research
Redlands, California, 92374
Boston Clinical Trials
Roslindale, Massachusetts, 02131
California Mental Behavioral Health
Santee, California, 92071
Scottsdale Clinical Research
Scottsdale, Arizona, 85260
Schuster Medical Research Institute SMRI
Sherman Oaks, California, 91403
Benchmark Research
Shreveport, Louisiana, 71101
Renew Health Clinical Research
Snellville, Georgia, 30078
K2 Medical Research
Tampa, Florida, 33607
Interventional Psychiatry of Tampa Bay
Tampa, Florida, 33629
Viking Clinical Research
Temecula, California, 92591
Collaborative Neuroscience Research LLC
Torrance, California, 90504
DelSol Research
Tucson, Arizona, 85715
Sunwise Clinical Research with is in Lafayette, CA
Walnut Creek, California, 94596
AMR Convention Research
Warrenville, Illinois, 60555
Adams Clinical
Watertown, Massachusetts, 02471
Suburban Research Associates
West Chester, Pennsylvania, 19380
Vitalix Clinical
Worcester, Massachusetts, 01608
Bulgaria5 sites
Diagnostic Consultive Center Higya AD
Pazardzhik, 4400
Ambulatory for Group Practice for Specialized Psychiatrics Help PHILIPOPOLIS OOD
Plovdiv, 4002
Medical Center Sveti Naum
Sofia, 1113
DCC-Mladost M OOD
Varna, 9020
Mental Health Center Vratsa
Vratsa, 3000
Germany5 sites
Pharmakologisches Studienzentrum Chemnitz GmbH
Chemnitz, MA, 09111
Somni Bene Institut for Medical Research
Schwerin, Mecklenburg, 19053
Private Practice Kusserow
Stralsund, Mecklenburg-Vorpommern, 18439
Arztepartnerschaft Dr. med. J. Springhub/ W. Schwarz-Studienzentrum Nord-West
Westerstede, 26655
Velocity Clinical Research Wiesbaden
Wiesbaden, Hesse, 65189
Poland5 sites
MlynowaMed - Bialystok
Bialystok, OH, 15-404
Osrodek Badan Klinicznych CLINSANTE
Bydgoszcz, Kuyavian-Pomeranian Voivodeship, 85-794
Centrum Medyczne Luxmed Sp.z. o.o.
Lublin, 20-109
Praktyka Lekarska Malgorzata Wojtanowska-Bogacka
Poznan, Greater Poland Voivodeship, 60-192
Indywidualna SpecjalistycznaPraktyka Lekarska AgnieszkaRemlinger-Molenda
Szkolkarska 32, 62-002
Czechia4 sites
BRAIN-SOULTHERAPY s.r.o.
Kladno, Central Bohemia, 272 01
National Institute of Mental Health
Klecany, 25067
Clintrial s.r.o.
Prague, 10000
A-Shine s.r.o.
Ptzen, Plzeň Region, 30100
Canada3 sites
Chatham-Kent Clinical Trials Research Centre
Chatham, Ontario, N7L 1C1
Institute of Mental Health Research IMHR
Ottawa, Ontario, K1Z 7K4
Centre for Addiction and Mental Health (CAMH & University of Toronto)
Toronto, Ontario, M6J 1H4
Hungary2 sites
ClinExpert Kft.
Budapest, 1033
Semmelweis University
Budapest, M6J 1H4
About this study
Official title: A Phase 2/3, Multicenter, Randomized, Double-blind, Placebo-controlled Trial of the Safety and Efficacy of Flexible Doses of SEP-363856 as Adjunctive Therapy in the Treatment of Adults With Major Depressive Disorder
Demonstrate ability of SEP-363856 to be superior to placebo as an adjunctive therapy to ADT in change from baseline in depressive symptoms (MADRS \& CGI-S) in MDD patients who had an inadequate response to prior ADT therapy.
- Conditions
- Major Depressive Disorder
- Being tested
- SEP-363856, Placebo
- Keywords
- MDD, SEP-363856, Antidepressant Therapy, ADT, Depression, Depressive Disorder, Major Mood Disorders, Mental Disorders
- Medical subject headings
- Depressive Disorder, Major, Depression, Depressive Disorder, Mental Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SEP-363856Drug
Tablet
PlaceboOther
Placebo
| Study group | Role | What they receive |
|---|---|---|
| SEP-363856 & ADT (Antidepressant Therapy) | Experimental | Not described Receives: Drug: SEP-363856 |
| Placebo & ADT (Antidepressant Therapy) | Placebo comparator | Not described Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Montgomery Åsberg Depression Rating Scale (MADRS)
Change from the baseline to the Montgomery Åsberg Depression Rating Scale (MADRS) total score.
The Montgomery Åsberg Depression Rating Scale consists of 10 items, each rated from 0 to 6 (for a total score of 0 to 60). A higher score represents a higher severity of the level of depression.
Measured: From baseline to week 14
Secondary outcomes (1)
Clinical Global Impression - Severity of Illness (CGI-S)
Change from baseline in the Clinical Global Impression - Severity of Illness (CGI-S).
Clinical Global Impression - Severity of Illness will be measured on a scale from 1-7 where a higher score represents a higher severity of disease.
Measured: From baseline to week 14
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Oct 2022
- Study start9 Nov 2022
- Primary completion6 Nov 2025
- Study completion13 Nov 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Major Depressive DisorderStudies of the same condition, open and under way.
- More trials run by Otsuka Pharmaceutical Development & Commercialization, Inc.The sponsor's other registered studies.
- 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
- Single blind
- Who is masked
- Participant
- Enrolment
- 929 participants (actual)
Sponsor and investigators
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05593029
- Sponsor's protocol ID
- 382-201-00001
- Status last verified
- Nov 2025
- First submitted
- 10 Oct 2022
- Last updated
- 18 Feb 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Anonymized Individual participant data (IPD) that underlie the results of this study will be shared with researchers to achieve aims pre-specified in a methodologically sound research proposal. Small studies with less than 25 participants are excluded from data sharing.
Study at a glance
From the registry record, last updated by the sponsor on 18 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2/3, Multicenter, Randomized, Double-blind, Placebo-controlled Trial of the Safety and Efficacy of Flexible Doses of SEP-363856 as Adjunctive Therapy in the Treatment of Adults With Major Depressive Disorder
- ClinicalTrials.gov ID
- NCT05593029
- Acronym / sponsor ID
- 382-201-00001
- Conditions
- Major Depressive Disorder
- Keywords
- MDD, SEP-363856, Antidepressant Therapy, ADT, Depression, Depressive Disorder, Major Mood Disorders, Mental Disorders
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 929 participants (actual)
- Lead sponsor
- Otsuka Pharmaceutical Development & Commercialization, Inc.Industry (pharma, biotech, devices)
- Study start
- 9 Nov 2022 (actual)
- Primary completion
- 6 Nov 2025 (actual)
- Study completion
- 13 Nov 2025 (actual)
- First posted
- 25 Oct 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Demonstrate ability of SEP-363856 to be superior to placebo as an adjunctive therapy to ADT in change from baseline in depressive symptoms (MADRS \& CGI-S) in MDD patients who had an inadequate response to prior ADT therapy.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| SEP-363856 & ADT (Antidepressant Therapy) | Experimental | Drug: SEP-363856 |
| Placebo & ADT (Antidepressant Therapy) | Placebo comparator | Other: Placebo |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Male and Female subjects between 18-65 years of age, with a primary diagnosis of major depressive disorder and in a current major depressive episode
- Current major depressive episode must be at least 8 weeks and no longer than 2 years in duration
- History of an inadequate response to at least 1 and no more than 3 antidepressant treatments in the current major depressive episode
Key exclusion criteria (4 listed)
- Subjects who report an inadequate response to more than 3 antidepressant treatments in the current episode
- Subjects with a lifetime history of schizophrenia spectrum or other psychotic disorder, bipolar or related disorder, major or mild neurocognitive disorder, 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, borderline or antisocial personality disorder.
- Subjects with a current diagnosis of post-traumatic stress disorder, obsessive compulsive disorder, panic disorder, or eating disorder (including anorexia nervosa or bulimia).
- Sexually active subjects, who could become pregnant, not agreeing to practice 2 sponsor approved methods of birth control or remain abstinent during the trial and for 30 days (females) or 90 days (males) after last dose of study drug.
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 |
|---|---|---|
| SEP-363856Tablet | Drug | SEP-363856 & ADT (Antidepressant Therapy) |
| PlaceboPlacebo | Other | Placebo & ADT (Antidepressant Therapy) |
Primary outcome
Montgomery Åsberg Depression Rating Scale (MADRS)
Time frame: From baseline to week 14
Change from the baseline to the Montgomery Åsberg Depression Rating Scale (MADRS) total score. The Montgomery Åsberg Depression Rating Scale consists of 10 items, each rated from 0 to 6 (for a total score of 0 to 60). A higher score represents a higher severity of the level of depression.
1 secondary outcome
Clinical Global Impression - Severity of Illness (CGI-S)
Time frame: From baseline to week 14
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Feb 2026.
- Otsuka Clinical Trials WebsiteLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. Anonymized Individual participant data (IPD) that underlie the results of this study will be shared with researchers to achieve aims pre-specified in a methodologically sound research proposal. Small studies with less than 25 participants are excluded from data sharing.
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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.
77 sites in 7 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing SEP-363856 in people with Major Depressive Disorder, run by Otsuka Pharmaceutical Development & Commercialization, Inc. at 77 sites in 7 countries.
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 3 inclusion and 4 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 18 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 77 sites in United States, Bulgaria, Germany, Poland, Czechia and 2 more countries. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Montgomery Åsberg Depression Rating Scale (MADRS) (time frame: From baseline to week 14). 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 18 Feb 2026.