Protocol Lay Person Short Title: A Trial of the Safety and Efficacy of Flexible Doses of SEP-363856 as Adjunctive Therapy in the Treatment of Adults with Major Depressive Disorder.

Phase 1

Recruiting

Conditions: Adjunctive therapy to antidepressants for the treatment of major depressive disorder (MDD) in adults.
Therapeutic area: Diseases [C] - Nervous System Diseases [C10]

Registration Number: CTIS2022-500538-27-00

Lead Sponsor: Otsuka Pharmaceutical Development And Commercialization Inc.

Brief Summary: Not available

Detailed Description: Not available

Recruitment & Eligibility

Status: Recruiting

Sex: All

Target Recruitment: 900

Inclusion Criteria

The study population includes subjects 18 to 65 years of age inclusive at the time of consent with MDD as the main diagnosis and who are currently experiencing a major depressive episode (MDE) as determined by the DSM-5 criteria (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition) and confirmed by the Structured Clinical Interview for DSM-5, Clinical Trials Version (SCID-5-CT) and appropriate clinical psychiatric assessment. The current MDE must have a duration of = 8 weeks and < 2 years. In addition, subjects must have reported a history for the current MDE of an inadequate response to at least 1 and no more than 3 adequate ADTs. Subjects must also have a total score = 18 at the screening and baseline visit on the 17-item Hamilton Depression Rating Scale (HAM-D17).

Exclusion Criteria

Any subject who, in the opinion of the clinical trial sponsor, investigator, or medical monitor, should not participate in the trial will be excluded.

Study & Design

Study Type: Interventional clinical trial of medicinal product

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Main Objective: To compare the efficacy of SEP-363856 (50 to 75 mg/day) to placebo as adjunctive therapy to an assigned open-label ADT in subjects with MDD who demonstrate an inadequate response to a prospective 8-week trial of the same assigned open label ADT.;Secondary Objective: To evaluate the safety and tolerability of SEP-363856 (50 to 75 mg/day) as adjunctive therapy to ADT in subjects with MDD.;Primary end point(s): Change from the end of Phase A (Week 8 visit) to the end of Phase B (Week 14 visit) in the MADRS total score.

Secondary Outcome Measures

Name	Time	Method
Secondary end point(s):Standard safety variables to be examined in this trial will include AEs, physical examinations (including body weight and waist circumference), vital signs (blood pressure, heart rate, and body temperature), 12-lead ECGs, and clinical laboratory assessments (hematology, serum chemistry, urinalysis, prolactin, glycosylated hemoglobin, and coagulation parameters).;Secondary end point(s):In addition to the standard safety variables, other safety variables including C-SSRS, SAS, AIMS, BARS, CSFQ, and PSQI will also be evaluated.