Trial Outcomes & Findings for An Extension Study to a Clinical Study That Will Continue to Evaluate the Effectiveness and Safety of SEP-363856 in People With Schizophrenia That Switch to SEP-363856 From Their From Their Current Antipsychotic Medication (NCT NCT05741528)

Results Overview

An AE is any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease occurring after the administration of a medicinal (investigational) product, whether or not considered related to the medicinal (investigational) product.

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

75 participants

Primary outcome timeframe

From first dose of study drug up to end of 1 week follow up period (up to Week 25)

Results posted on

2025-11-12

Participant Flow

Participants took part in the study at 16 clinical sites in the United States (US) from 31 March 2023 to 23 September 2024.

A total of 75 participants rolled over from Study SEP361-308 (NCT05628103) into Study SEP361-309, and all 75 participants received at least one dose of SEP-363856 in the 24-week treatment period.

Participant milestones

Participant milestones
Measure	SEP-363856 Participants received SEP-363856 at the same dose they were taking upon completion of Study SEP361-308 (NCT05628103), orally, once daily (QD). Thereafter, the dose was adjusted within the range of 50 milligrams/day (mg/day) to 100 mg/day in 25 milligrams (mg) increments (i.e. 50 mg/day, 75 mg/day, or 100 mg/day), based on clinical judgment. Participants continued to receive flexible dose of SEP-363856 (50 mg/day to 100 mg/day) up to Week 24.
Overall Study STARTED	75
Overall Study COMPLETED	56
Overall Study NOT COMPLETED	19

Reasons for withdrawal

Reasons for withdrawal
Measure	SEP-363856 Participants received SEP-363856 at the same dose they were taking upon completion of Study SEP361-308 (NCT05628103), orally, once daily (QD). Thereafter, the dose was adjusted within the range of 50 milligrams/day (mg/day) to 100 mg/day in 25 milligrams (mg) increments (i.e. 50 mg/day, 75 mg/day, or 100 mg/day), based on clinical judgment. Participants continued to receive flexible dose of SEP-363856 (50 mg/day to 100 mg/day) up to Week 24.
Overall Study Withdrawal by Subject	11
Overall Study Lost to Follow-up	3
Overall Study Adverse Event	2
Overall Study Non-Compliance With Study Drug	2
Overall Study Reason Not Specified	1

Baseline Characteristics

An Extension Study to a Clinical Study That Will Continue to Evaluate the Effectiveness and Safety of SEP-363856 in People With Schizophrenia That Switch to SEP-363856 From Their From Their Current Antipsychotic Medication

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	SEP-363856 n=75 Participants Participants received SEP-363856 at the same dose they were taking upon completion of Study SEP361-308 (NCT05628103), orally, QD. Thereafter, the dose was adjusted within the range of 50 mg/day to 100 mg/day in 25 mg increments (i.e. 50 mg/day, 75 mg/day, or 100 mg/day), based on clinical judgment. Participants continued to receive flexible dose of SEP-363856 (50 mg/day to 100 mg/day) up to Week 24.
Age, Continuous	49.7 years STANDARD_DEVIATION 11.41 • n=10 Participants
Sex: Female, Male Female	22 Participants n=10 Participants
Sex: Female, Male Male	53 Participants n=10 Participants
Race/Ethnicity, Customized Race · Asian	2 Participants n=10 Participants
Race/Ethnicity, Customized Race · Black or African American	49 Participants n=10 Participants
Race/Ethnicity, Customized Race · White	23 Participants n=10 Participants
Race/Ethnicity, Customized Race · Multiracial	1 Participants n=10 Participants
Race/Ethnicity, Customized Ethnicity · Hispanic or Latino	13 Participants n=10 Participants
Race/Ethnicity, Customized Ethnicity · Not Hispanic or Latino	62 Participants n=10 Participants

PRIMARY outcome

Timeframe: From first dose of study drug up to end of 1 week follow up period (up to Week 25)

Population: Safety population included all participants who received at least one dose of study drug during the 24-week OLE treatment period.

An AE is any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease occurring after the administration of a medicinal (investigational) product, whether or not considered related to the medicinal (investigational) product.

Outcome measures

Outcome measures
Measure	SEP-363856 n=75 Participants Participants received SEP-363856 at the same dose they were taking upon completion of Study SEP361-308 (NCT05628103), orally, QD. Thereafter, the dose was adjusted within the range of 50 mg/day to 100 mg/day in 25 mg increments (i.e. 50 mg/day, 75 mg/day, or 100 mg/day), based on clinical judgment. Participants continued to receive flexible dose of SEP-363856 (50 mg/day to 100 mg/day) up to Week 24.
Number of Participants With Adverse Events (AEs)	28 Participants

PRIMARY outcome

Timeframe: From first dose of study drug up to end of 1 week follow up period (up to Week 25)

Population: Safety population included all participants who received at least one dose of study drug during the 24-week OLE treatment period.

An AE is any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease occurring after the administration of a medicinal (investigational) product, whether or not considered related to the medicinal (investigational) product. A serious adverse event is any AE occurring at any dose that results in death, is life-threatening, results in persistent or significant disability/incapacity, requires in-patient hospitalization or prolongation of existing hospitalization, or is a congenital anomaly/birth defect.

Outcome measures

Outcome measures
Measure	SEP-363856 n=75 Participants Participants received SEP-363856 at the same dose they were taking upon completion of Study SEP361-308 (NCT05628103), orally, QD. Thereafter, the dose was adjusted within the range of 50 mg/day to 100 mg/day in 25 mg increments (i.e. 50 mg/day, 75 mg/day, or 100 mg/day), based on clinical judgment. Participants continued to receive flexible dose of SEP-363856 (50 mg/day to 100 mg/day) up to Week 24.
Number of Participants With Serious Adverse Events	4 Participants

PRIMARY outcome

Timeframe: From first dose of study drug up to end of 1 week follow up period (up to Week 25)

Population: Safety population included all participants who received at least one dose of study drug during the 24-week OLE treatment period.

An AE is any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease occurring after the administration of a medicinal (investigational) product, whether or not considered related to the medicinal (investigational) product. AEs leading to discontinuation from the study are those AEs which caused participant to discontinue from the study.

Outcome measures

Outcome measures
Measure	SEP-363856 n=75 Participants Participants received SEP-363856 at the same dose they were taking upon completion of Study SEP361-308 (NCT05628103), orally, QD. Thereafter, the dose was adjusted within the range of 50 mg/day to 100 mg/day in 25 mg increments (i.e. 50 mg/day, 75 mg/day, or 100 mg/day), based on clinical judgment. Participants continued to receive flexible dose of SEP-363856 (50 mg/day to 100 mg/day) up to Week 24.
Number of Participants With AEs Leading to Discontinuation of Study	1 Participants

Adverse Events

SEP-363856

Serious events: 4 serious events

Other events: 9 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	SEP-363856 n=75 participants at risk Participants received SEP-363856 at the same dose they were taking upon completion of Study SEP361-308 (NCT05628103), orally, QD. Thereafter, the dose was adjusted within the range of 50 mg/day to 100 mg/day in 25 mg increments (i.e. 50 mg/day, 75 mg/day, or 100 mg/day), based on clinical judgment. Participants continued to receive flexible dose of SEP-363856 (50 mg/day to 100 mg/day) up to Week 24.
Psychiatric disorders Delusion	1.3% 1/75 • From first dose of study drug up to end of 1 week follow up period (up to Week 25) Safety population included all participants who received at least one dose of study drug during the 24-week OLE treatment period.
Psychiatric disorders Psychotic disorder	1.3% 1/75 • From first dose of study drug up to end of 1 week follow up period (up to Week 25) Safety population included all participants who received at least one dose of study drug during the 24-week OLE treatment period.
Psychiatric disorders Schizophrenia	1.3% 1/75 • From first dose of study drug up to end of 1 week follow up period (up to Week 25) Safety population included all participants who received at least one dose of study drug during the 24-week OLE treatment period.
Vascular disorders Hypotension	1.3% 1/75 • From first dose of study drug up to end of 1 week follow up period (up to Week 25) Safety population included all participants who received at least one dose of study drug during the 24-week OLE treatment period.

Other adverse events

Other adverse events
Measure	SEP-363856 n=75 participants at risk Participants received SEP-363856 at the same dose they were taking upon completion of Study SEP361-308 (NCT05628103), orally, QD. Thereafter, the dose was adjusted within the range of 50 mg/day to 100 mg/day in 25 mg increments (i.e. 50 mg/day, 75 mg/day, or 100 mg/day), based on clinical judgment. Participants continued to receive flexible dose of SEP-363856 (50 mg/day to 100 mg/day) up to Week 24.
Investigations Weight decreased	6.7% 5/75 • From first dose of study drug up to end of 1 week follow up period (up to Week 25) Safety population included all participants who received at least one dose of study drug during the 24-week OLE treatment period.
Investigations C-reactive protein increased	5.3% 4/75 • From first dose of study drug up to end of 1 week follow up period (up to Week 25) Safety population included all participants who received at least one dose of study drug during the 24-week OLE treatment period.

Additional Information

Clinical Transparency

Otsuka Pharmaceutical Development & Commercialization, Inc.

Phone: 08446878522

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place