A Trial of the Safety and Efficacy of SEP-363856 in the Treatment of Adults With Major Depressive Disorder

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

Status

Completed

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05593029

Enrollment

929

Registered

2022-10-25

Start date

2022-11-09

Completion date

2025-11-13

Last updated

2026-02-18

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Major Depressive Disorder

Keywords

MDD, SEP-363856, Antidepressant Therapy, ADT, Depression, Depressive Disorder, Major Mood Disorders, Mental Disorders

Brief 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.

Interventions

DRUGSEP-363856

Tablet

OTHERPlacebo

Placebo

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

SINGLE (Subject)

Eligibility

Sex/Gender

ALL

Age

18 Years to 65 Years

Healthy volunteers

Inclusion criteria

* 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

Exclusion criteria

* 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.

Design outcomes

Primary

Measure	Time frame	Description
Montgomery Åsberg Depression Rating Scale (MADRS)	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.

Secondary

Measure	Time frame	Description
Clinical Global Impression - Severity of Illness (CGI-S)	From baseline to week 14	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.

Countries

Bulgaria, Canada, Czechia, Germany, Hungary, Poland, United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 19, 2026