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An Extension Study to Assess Long-term Safety, Tolerability, and Efficacy of KarXT in Adult Patients With Schizophrenia (EMERGENT-4)

An Open-label Extension Study to Assess the Long-term Safety, Tolerability, and Efficacy of KarXT in Subjects With DSM-5 Schizophrenia

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04659174
Enrollment
152
Registered
2020-12-09
Start date
2021-02-01
Completion date
2023-10-03
Last updated
2024-10-28

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

Conditions

Schizophrenia

Brief summary

This is a Phase 3, multicenter, 53-week, outpatient, open-label extension (OLE) study to evaluate the long-term safety, tolerability, and efficacy of KarXT in subjects with Diagnostic and Statistical Manual-Fifth Edition (DSM-5) schizophrenia who previously completed the treatment period of one of the two Phase 3 double-blind studies, KAR-007 or KAR-009. In this OLE study, all subjects will receive KarXT (a fixed combination of xanomeline 125 mg and trospium chloride 30 mg twice daily \[BID\]) for up to 52 weeks regardless of treatment assignment in the preceding Phase 3 acute study. The primary objective of the study is to assess the long-term safety and tolerability of KarXT in subjects with a DSM-5 diagnosis of schizophrenia. The secondary objective of this study is to assess the long-term efficacy and monitor trough concentrations of xanomeline and trospium after administration of KarXT.

Interventions

Oral xanomeline 50 mg/trospium chloride 20 mg BID on days 1-2 followed by xanomeline 100 mg/trospium chloride 20 mg BID on days 3-7. The dosage is increased to xanomeline 125 mg/trospium chloride 30 mg BID on days 8-364 unless the subject is experiencing adverse events from the xanomeline 100 mg/ trospium chloride 20 mg dose. Subjects who were increased to xanomeline 125 mg/trospium chloride 30 mg will have the option to return to xanomeline 100 mg/ trospium chloride 20 mg depending on clinical response and tolerability. Re-escalation to 125/30 BID or re-titration in cases in which the subject has been off KarXT for a longer period of time (at least a week) is allowed and will require a discussion between the principal investigator and the medical monitor.

Sponsors

Karuna Therapeutics
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No

Inclusion criteria

1. Subject is aged 18 to 65 years, at time of enrollment into the preceding acute study (KAR-007/009). 2. Subject is capable of providing informed consent. 1. A signed informed consent form must be provided before any study assessments are performed. 2. Subject must be fluent in (oral and written) English (United States only) or local language (Ukraine only) to consent. 3. Subject has completed the treatment period on study drug (through Day 35 -2 days) of Studies KAR-007 or KAR-009. 4. Subject resides in a stable living situation, in the opinion of the investigator. 5. Subject has an identified, reliable informant/caregiver willing to be able to address some questions related to certain study visits, if needed. An informant/caregiver may not be necessary if the subject has been the patient of the investigator for ≥1 year. 6. Women of childbearing potential or men with sexual partners of childbearing potential must be sexually abstinent (in line with their preferred and usual lifestyle) or willing and able to use at least 1 highly effective method of contraception during the study and for at least 7 days after the last dose of KarXT. Sperm donation is not allowed for 7 days after the final dose of KarXT.

Exclusion criteria

1. Risk for suicidal behavior during the study as determined by the investigator's clinical assessment and Columbia-Suicide Severity Rating Scale (C-SSRS). 2. Any clinically significant abnormality, including any finding(s) from the physical examination, vital signs, ECG, or laboratory test at the end-of-treatment visit of Studies KAR-007 or KAR-009 that the investigator, in consultation with the medical monitor, would consider to jeopardize the safety of the subject. 3. Female subject is pregnant. 4. If, in the opinion of the investigator (and/or Sponsor), subject is unsuitable for enrollment in the study or subject has any finding that, in the view of the investigator (and/or Sponsor), may compromise the safety of the subject or affect his/her ability to adhere to the protocol visit schedule or fulfill visit requirements. 5. Subjects with extreme concerns relating to global pandemics such as coronavirus disease 2019 (COVID-19) that preclude study participation. 6. Risk of violent or destructive behavior. 7. Subjects participating in another investigational drug or device trial or planning on participating in another clinical trial during the course of the study.

Design outcomes

Primary

MeasureTime frameDescription
Number of Participants With Treatment-Emergent Adverse Events (TEAEs)From first dose to end of study (Up to approximately 53 weeks)TEAEs are defined as events with an onset date on or after the first dose of KarXT. An Adverse Event is any symptom, physical sign, syndrome, or disease that either emerges during the study or, if present at baseline, worsens during the study, regardless of the suspected cause of the event using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), version 5.0.

Secondary

MeasureTime frameDescription
Number of Participants With Treatment-Emergent Adverse Events (TEAE) Leading to Study Drug DiscontinuationFrom first dose to end of study (Up to approximately 53 weeks)TEAEs are defined as events with an onset date on or after the first dose of KarXT. An Adverse Event is any symptom, physical sign, syndrome, or disease that either emerges during the study or, if present at baseline, worsens during the study, regardless of the suspected cause of the event using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), version 5.0.
Change From Baseline in Positive and Negative Syndrome Scale (PANSS) Total Score at Week 52Open-label extension baseline, week 52The PANSS rating form contains 7 positive symptom scales, 7 negative system scales, and 16 general psychopathology symptom scales. Participants are rated from 1 to 7 on each symptom scale. The positive symptoms in schizophrenia are the excess or distortion of normal function and the negative symptoms are the diminution or loss of normal functions. PANSS total score is the sum of all 30 items with a minimum score of 30 and a maximum score of 210. Higher scores indicate more severe symptoms. Open-label Extension Baseline (OLEB) is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.
Change From Baseline in Positive and Negative Syndrome Scale (PANSS) Positive Score at Week 52Open-labe extension baseline, week 52PANSS positive score is the sum of all PANSS 7 positive symptom scales with a minimum score of 7 and a maximum score of 49. Higher scores indicate more severe symptoms. Participants are rated from 1 to 7 on each symptom scale. The positive symptoms in schizophrenia are the excess or distortion of normal function such as hallucinations, delusions, grandiosity, and hostility. Open-label Extension Baseline (OLEB) is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.
Number of Participants With Serious Adverse Events (SAEs)From first dose to end of study (Up to approximately 53 weeks)An SAE is any untoward medical occurrence, in the view of either the investigator or sponsor, that results in death; is life-threatening; results in inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity, and/or; is a congenital anomaly/birth defect using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), version 5.0.
Change From Baseline in PANSS Negative Marder Factor Score at Week 52Open-label extension baseline, week 52PANSS Negative Marder Factor Score is the sum of 5 negative scales and 2 general scales (N1. Blunted affect; N2. Emotional withdrawal; N3. Poor rapport; N4. Passive/apathetic social withdrawal; N6. Lack of spontaneity; G7. Motor retardation; and G16. Active social avoidance). Participants are rated from 1 to 7 on each symptom scale. Higher score indicates more severe symptoms. The negative symptoms in schizophrenia are the diminution or loss of normal functions. Open-label Extension Baseline (OLEB) is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.
Change From Baseline in Clinical Global Impression-Severity (CGI-S) Score at Week 52Open-label extension baseline, week 52Completed independently by a clinician, the CGI-S categorizes the severity of the illness as: 1 = Normal, not at all ill; 2 = Borderline mentally ill; 3 = Mildly ill; 4 = Moderately ill; 5 = Markedly ill; 6 = Severely ill; and 7 = Among the most extremely ill patients, by asking the clinical 1 question and providing a rating based upon observed and reported symptoms, behavior, and function in the past 7 days to reflect the average severity level across the 7 days. Higher score indicates more severe illness. Open-label Extension Baseline (OLEB) is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.
Percentage of PANSS Responders With >=30% Reduction in PANSS Total Score at Week 52At week 52A PANSS responder is defined as a participant with reduction from open-label extension baseline (OLEB) of at least a 30% improvement at Week 52 in the PANSS total score. The PANSS rating form contains 7 positive symptom scales, 7 negative system scales, and 16 general psychopathology symptom scales. Participants are rated from 1 to 7 on each symptom scale. PANSS total score is the sum of all 30 items with a minimum score of 30 and a maximum score of 210. Higher scores indicate more severe symptoms. OLEB is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.
Change From Baseline in Positive and Negative Syndrome Scale (PANSS) Negative Score at Week 52Open-label extension baseline, week 52PANSS negative score is the sum of all PANSS 7 negative symptom scales with a minimum score of 7 and a maximum score of 49. Higher scores indicate more severe symptoms. Participants are rated from 1 to 7 on each symptom scale. The negative symptoms in schizophrenia are the diminution or loss of normal functions. Open-label Extension Baseline (OLEB) is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.

Countries

Ukraine, United States

Participant flow

Participants by arm

ArmCount
KarXT Arm A
Lead-in doses of KarXT (KarXT 50/20 BID). Dosing will be titrated to 100/20 BID on Days 3 to 7 and further titrated to 125/30 BID on Day 8, unless the participant continues to experience AE(s) from the previous dose increase of KarXT. All participants will have the option to return to KarXT 100/20 BID for the remainder of the treatment period. Participants received KarXT previously from KAR-007 and KAR-009.
68
KarXT Arm B
Lead-in doses of KarXT (KarXT 50/20 BID). Dosing will be titrated to 100/20 BID on Days 3 to 7 and further titrated to 125/30 BID on Day 8, unless the participant continues to experience AE(s) from the previous dose increase of KarXT. All participants will have the option to return to KarXT 100/20 BID for the remainder of the treatment period. Participants received Placebo previously from KAR-007 and KAR-009.
84
Total152

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyAdverse Event85
Overall StudyAlcohol or illegal drug use03
Overall StudyDeath01
Overall StudyLost to Follow-up911
Overall StudyOther reasons02
Overall StudyParticipant fails to adhere to the protocol requirements149
Overall StudyProgressive disease02
Overall StudySponsor decision to discontinue study02
Overall StudyViolation of entry criteria10
Overall StudyWithdrawal by Subject1733

Baseline characteristics

CharacteristicKarXT Arm BTotalKarXT Arm A
Age, Continuous43.3 Years
STANDARD_DEVIATION 12.07
44.9 Years
STANDARD_DEVIATION 11.67
46.8 Years
STANDARD_DEVIATION 10.94
Ethnicity (NIH/OMB)
Hispanic or Latino
8 Participants12 Participants4 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
76 Participants140 Participants64 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants
Race/Ethnicity, Customized
American Indian or Alaska Native
0 Participants0 Participants0 Participants
Race/Ethnicity, Customized
Asian
0 Participants1 Participants1 Participants
Race/Ethnicity, Customized
Black or African American
47 Participants93 Participants46 Participants
Race/Ethnicity, Customized
Native Hawaiian or Other Pacific Islander
0 Participants0 Participants0 Participants
Race/Ethnicity, Customized
Other
2 Participants2 Participants0 Participants
Race/Ethnicity, Customized
Unknown or Not Reported
0 Participants0 Participants0 Participants
Race/Ethnicity, Customized
White
35 Participants56 Participants21 Participants
Sex: Female, Male
Female
18 Participants38 Participants20 Participants
Sex: Female, Male
Male
66 Participants114 Participants48 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
0 / 681 / 84
other
Total, other adverse events
19 / 6831 / 84
serious
Total, serious adverse events
5 / 683 / 84

Outcome results

Primary

Number of Participants With Treatment-Emergent Adverse Events (TEAEs)

TEAEs are defined as events with an onset date on or after the first dose of KarXT. An Adverse Event is any symptom, physical sign, syndrome, or disease that either emerges during the study or, if present at baseline, worsens during the study, regardless of the suspected cause of the event using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), version 5.0.

Time frame: From first dose to end of study (Up to approximately 53 weeks)

Population: All treated participants

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
KarXT Arm ANumber of Participants With Treatment-Emergent Adverse Events (TEAEs)36 Participants
KarXT Arm BNumber of Participants With Treatment-Emergent Adverse Events (TEAEs)45 Participants
Secondary

Change From Baseline in Clinical Global Impression-Severity (CGI-S) Score at Week 52

Completed independently by a clinician, the CGI-S categorizes the severity of the illness as: 1 = Normal, not at all ill; 2 = Borderline mentally ill; 3 = Mildly ill; 4 = Moderately ill; 5 = Markedly ill; 6 = Severely ill; and 7 = Among the most extremely ill patients, by asking the clinical 1 question and providing a rating based upon observed and reported symptoms, behavior, and function in the past 7 days to reflect the average severity level across the 7 days. Higher score indicates more severe illness. Open-label Extension Baseline (OLEB) is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.

Time frame: Open-label extension baseline, week 52

Population: All participants who received at least 1 dose of KarXT and have a valid post-baseline CGI-S assessment

ArmMeasureValue (MEAN)Dispersion
KarXT Arm AChange From Baseline in Clinical Global Impression-Severity (CGI-S) Score at Week 52-0.5 score on a scaleStandard Deviation 1.12
KarXT Arm BChange From Baseline in Clinical Global Impression-Severity (CGI-S) Score at Week 52-1.2 score on a scaleStandard Deviation 1.6
Secondary

Change From Baseline in PANSS Negative Marder Factor Score at Week 52

PANSS Negative Marder Factor Score is the sum of 5 negative scales and 2 general scales (N1. Blunted affect; N2. Emotional withdrawal; N3. Poor rapport; N4. Passive/apathetic social withdrawal; N6. Lack of spontaneity; G7. Motor retardation; and G16. Active social avoidance). Participants are rated from 1 to 7 on each symptom scale. Higher score indicates more severe symptoms. The negative symptoms in schizophrenia are the diminution or loss of normal functions. Open-label Extension Baseline (OLEB) is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.

Time frame: Open-label extension baseline, week 52

Population: All participants who received at least 1 dose of KarXT and have a valid post-baseline PANSS assessment

ArmMeasureValue (MEAN)Dispersion
KarXT Arm AChange From Baseline in PANSS Negative Marder Factor Score at Week 52-2.4 score on a scaleStandard Deviation 4.22
KarXT Arm BChange From Baseline in PANSS Negative Marder Factor Score at Week 52-5.1 score on a scaleStandard Deviation 5.67
Secondary

Change From Baseline in Positive and Negative Syndrome Scale (PANSS) Negative Score at Week 52

PANSS negative score is the sum of all PANSS 7 negative symptom scales with a minimum score of 7 and a maximum score of 49. Higher scores indicate more severe symptoms. Participants are rated from 1 to 7 on each symptom scale. The negative symptoms in schizophrenia are the diminution or loss of normal functions. Open-label Extension Baseline (OLEB) is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.

Time frame: Open-label extension baseline, week 52

Population: All participants who received at least 1 dose of KarXT and have a valid post-baseline PANSS assessment

ArmMeasureValue (MEAN)Dispersion
KarXT Arm AChange From Baseline in Positive and Negative Syndrome Scale (PANSS) Negative Score at Week 52-2.1 score on a scaleStandard Deviation 4.01
KarXT Arm BChange From Baseline in Positive and Negative Syndrome Scale (PANSS) Negative Score at Week 52-4.6 score on a scaleStandard Deviation 5.06
Secondary

Change From Baseline in Positive and Negative Syndrome Scale (PANSS) Positive Score at Week 52

PANSS positive score is the sum of all PANSS 7 positive symptom scales with a minimum score of 7 and a maximum score of 49. Higher scores indicate more severe symptoms. Participants are rated from 1 to 7 on each symptom scale. The positive symptoms in schizophrenia are the excess or distortion of normal function such as hallucinations, delusions, grandiosity, and hostility. Open-label Extension Baseline (OLEB) is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.

Time frame: Open-labe extension baseline, week 52

Population: All participants who received at least 1 dose of KarXT and have a valid post-baseline PANSS assessment

ArmMeasureValue (MEAN)Dispersion
KarXT Arm AChange From Baseline in Positive and Negative Syndrome Scale (PANSS) Positive Score at Week 52-3.2 score on a scaleStandard Deviation 5.85
KarXT Arm BChange From Baseline in Positive and Negative Syndrome Scale (PANSS) Positive Score at Week 52-7.8 score on a scaleStandard Deviation 6.38
Secondary

Change From Baseline in Positive and Negative Syndrome Scale (PANSS) Total Score at Week 52

The PANSS rating form contains 7 positive symptom scales, 7 negative system scales, and 16 general psychopathology symptom scales. Participants are rated from 1 to 7 on each symptom scale. The positive symptoms in schizophrenia are the excess or distortion of normal function and the negative symptoms are the diminution or loss of normal functions. PANSS total score is the sum of all 30 items with a minimum score of 30 and a maximum score of 210. Higher scores indicate more severe symptoms. Open-label Extension Baseline (OLEB) is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.

Time frame: Open-label extension baseline, week 52

Population: All participants who received at least 1 dose of KarXT and have a valid post-baseline PANSS assessment

ArmMeasureValue (MEAN)Dispersion
KarXT Arm AChange From Baseline in Positive and Negative Syndrome Scale (PANSS) Total Score at Week 52-9.0 score on a scaleStandard Deviation 17.33
KarXT Arm BChange From Baseline in Positive and Negative Syndrome Scale (PANSS) Total Score at Week 52-23.9 score on a scaleStandard Deviation 22.06
Secondary

Number of Participants With Serious Adverse Events (SAEs)

An SAE is any untoward medical occurrence, in the view of either the investigator or sponsor, that results in death; is life-threatening; results in inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity, and/or; is a congenital anomaly/birth defect using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), version 5.0.

Time frame: From first dose to end of study (Up to approximately 53 weeks)

Population: All treated participants

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
KarXT Arm ANumber of Participants With Serious Adverse Events (SAEs)5 Participants
KarXT Arm BNumber of Participants With Serious Adverse Events (SAEs)3 Participants
Secondary

Number of Participants With Treatment-Emergent Adverse Events (TEAE) Leading to Study Drug Discontinuation

TEAEs are defined as events with an onset date on or after the first dose of KarXT. An Adverse Event is any symptom, physical sign, syndrome, or disease that either emerges during the study or, if present at baseline, worsens during the study, regardless of the suspected cause of the event using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), version 5.0.

Time frame: From first dose to end of study (Up to approximately 53 weeks)

Population: All treated participants

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
KarXT Arm ANumber of Participants With Treatment-Emergent Adverse Events (TEAE) Leading to Study Drug Discontinuation9 Participants
KarXT Arm BNumber of Participants With Treatment-Emergent Adverse Events (TEAE) Leading to Study Drug Discontinuation7 Participants
Secondary

Percentage of PANSS Responders With >=30% Reduction in PANSS Total Score at Week 52

A PANSS responder is defined as a participant with reduction from open-label extension baseline (OLEB) of at least a 30% improvement at Week 52 in the PANSS total score. The PANSS rating form contains 7 positive symptom scales, 7 negative system scales, and 16 general psychopathology symptom scales. Participants are rated from 1 to 7 on each symptom scale. PANSS total score is the sum of all 30 items with a minimum score of 30 and a maximum score of 210. Higher scores indicate more severe symptoms. OLEB is defined as the most recent measurement prior to the first administration of study drug in KAR-008. The assessments performed on Visit 10 (Day 35) of studies KAR-007 or KAR-009 will be considered for OLEB baseline along with any additional procedures that will be performed on Day 0 of KAR-008.

Time frame: At week 52

Population: All participants who received at least 1 dose of KarXT and have a valid post-baseline PANSS assessment

ArmMeasureValue (NUMBER)
KarXT Arm APercentage of PANSS Responders With >=30% Reduction in PANSS Total Score at Week 5242.1 Percentage of participants
KarXT Arm BPercentage of PANSS Responders With >=30% Reduction in PANSS Total Score at Week 5256.3 Percentage of participants

Source: ClinicalTrials.gov · Data processed: Feb 12, 2026