The purpose of this study is to evaluate the efficacy and safety of adjunctive KarXT for the treatment of mania in participants with Bipolar-I Disorder.
Individuals have a primary diagnosis of Bipolar-I disorder established by a comprehensive psychiatric evaluation based on the DSM-5-TR criteria and confirmed by the Mini International Neuropsychiatric Interview (MINI) version 7.0.2.
Individual is experiencing an acute exacerbation or relapse of manic episode, with or without mixed features (≤ 3 weeks).
The individual requires hospitalization for the acute exacerbation or relapse of mania.
Body mass index ≥ 18 and ≤ 40 kg/m2.
Any primary DSM-5-TR disorder other than BP-I within 12 months before screening (confirmed using MINI version 7.0.2 at screening) including BP-I depression (for previous 3 months only), BP-I with rapid cycling, first manic episode, BP-II, primary psychotic disorder, borderline personality disorder, and major depressive disorder, with the exception of mild anxiety disorders.
Individual has a DSM-5-TR diagnosis of moderate to severe substance use disorder (except tobacco use disorder) within the 12 months before screening (confirmed using MINI version 7.0.2 at screening), or current use as determined by urine toxicology screen or alcohol test.
Risk for suicidal behavior at screening as determined by the investigator's clinical assessment and the C-SSRS with an answer "Yes" to item 4 or 5 within 6 months before screening or between screening and baseline, or "Yes" to any of the 5 items (C-SSRS behavior) with an event occurring within the 12 months before screening, or between screening and baseline.
History of irritable bowel syndrome (with or without constipation) or any serious constipation requiring treatment within the last 6 months.