A Phase 3, Randomized, Double-blind, Placebo-controlled, Study to Evaluate the Efficacy and Safety of Adjunctive KarXT for the Treatment of Mania, With or Without Mixed Features, in Individuals With Bipolar-I Disorder Taking Lithium, Valproate, or Lamotrigine

Inclusion Criteria: * 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. * Currently experiencing an acute episode of mania or mania with mixed features with a ther…