An Open-label Study to Assess the Long-term Safety, Tolerability, and Efficacy of KarXT in Adult Patients With Schizophrenia (EMERGENT-5)

Inclusion Criteria

• Subject is aged 18 to 65 years at screening.
• Subject is capable of providing informed consent.
• A signed informed consent form (ICF) must be provided before any study assessments are performed.
• Subject must be fluent in (oral and written) the language of the ICGF to consent.
• Subject has a primary diagnosis of schizophrenia established by a comprehensive psychiatric evaluation based on the DSM-5 (American Psychiatric Association 2013) criteria and confirmed by Mini International Neuropsychiatric Interview for Schizophrenia and Psychotic Disorder Studies (MINI) version 7.0.2.
• Subject has not required psychiatric hospitalization, acute crisis intervention, or other increase in level of care due to symptom exacerbation within 8 weeks of screening and is psychiatrically stable in the opinion of the investigator.
• PANSS total score ≤ 80 at screening and Baseline Visit B (Day 0).
• Clinical Global Impression - Severity (CGI-S) score of ≤ 4 at screening and Baseline Visit B (Day 0).
• At the time of screening, or at any time within the 30 days prior to screening, the subject must have received an oral antipsychotic medication daily at a dose and frequency consistent with the drug label.
• In the opinion of the investigator, it is clinically appropriate for the subject to discontinue current antipsychotic therapy and initiate experimental treatment with KarXT.
• Subject is willing and able, in the opinion of the investigator, to discontinue all antipsychotic medications prior to baseline visit.
• Subject has an identified reliable informant willing to be able to address some questions related to certain study visits, if needed. An informant may not be necessary if the subject has been the patient of the investigator for ≥1 year.
• At Day 0, subject will have been off lithium therapy for at least 2 weeks and must have discontinued all oral antipsychotic medications.
• Subjects taking a long-acting injectable antipsychotic could not have received a dose of medication for at least 12 weeks (24 weeks for paliperidone palmitate) before Day 0.
• Body mass index must be ≥ 18 and ≤ 40 kg/m2.
• Subject resides in a stable living situation and is anticipated to remain in a stable living situation for the duration of study enrollment, in the opinion of the investigator.
• Women of childbearing potential or men with sexual partners of childbearing potential must be willing and able to use at least 1 highly effective method of contraception during the study and for at least 30 days after the last dose of KarXT. Sperm donation is not allowed for 30 days after the final dose of KarXT.

Exclusion Criteria

• Any primary DSM-5 disorder other than schizophrenia within 12 months before screening (confirmed using MINI version 7.0.2 at screening).
• Subject has a history of moderate to severe alcohol use disorder or a substance (other than nicotine or caffeine) use disorder within the past 12 months or a positive urine drug screen (UDS) for a substance other than cannabis at screening or baseline.
• History or presence of clinically significant cardiovascular, pulmonary, hepatic, renal, hematologic, gastrointestinal, endocrine, immunologic, dermatologic, neurologic, or oncologic disease or any other condition that, in the opinion of the investigator, would jeopardize the safety of the subject or the validity of the study results
• Subject has human immunodeficiency virus (HIV), cirrhosis, biliary duct abnormalities, hepatobiliary carcinoma, and/or active hepatic viral infections based on either medical history or liver function test results.
• History or high risk of urinary retention, gastric retention, or narrow-angle glaucoma
• History of irritable bowel syndrome (with or without constipation) or serious constipation requiring treatment within the last 6 months
• Risk for suicidal behavior during the study as determined by the investigator's clinical assessment and Columbia-Suicide Severit