An Extension Study to Assess Long-Term Safety and Tolerability of Adjunctive KarXT in Subjects With Inadequately Controlled Symptoms of Schizophrenia

Inclusion Criteria:

1. Subject is aged ≥18 to <66 years at the time of randomization of Study KAR-012

2. Subject has successfully completed the treatment period of Study KAR-012

3. Subject has been compliant with the procedures in Study KAR-012 (in theInvestigator's judgement)

4. Subject has been compliant with their background antipsychotic drug in Study KAR-012in the opinion of the Investigator and based on subject and informant reportingNote: Subjects are required to remain on the same appropriate approved APD as inStudy KAR-012 and should stay on that same dose throughout the study.

5. Subject is capable of providing signed Informed Consent Form before any studyassessments will be performed

6. Subject resides in a stable living situation, in the opinion of the Investigator

7. Subject has identified a reliable informant/caregiver willing and able to assistwith study activities as needed throughout the subject's participation in the study.The informant can complete the study visits assessments via phone (as per localregulations). In Bulgaria, the informant needs to be physically present at all studyvisits where the Investigator determines that his/her input would be beneficial.

8. Women of childbearing potential (WOCP), or men whose sexual partners are WOCP, mustbe able and willing to use at least 1 highly effective method of contraceptionduring the study and for at least 1 menstrual cycle (e.g., 30 days) after the lastdose of study drug. Sperm donation is not allowed for 30 days after the final doseof the study drug. A female subject is considered to be a WOCP after menarche anduntil she is in a postmenopausal state for 12 months or otherwise permanentlysterile (for which acceptable methods include hysterectomy, bilateral salpingectomy,or bilateral oophorectomy).

Exclusion Criteria:

1. Risk for suicidal behavior during the study as determined by the Investigator'sclinical assessment and/or Columbia-Suicide Severity Rating Scale (C-SSRS) asconfirmed by the following:

2. Subject answers "Yes" to "suicidal ideation" Item 4 (active suicidal ideationwith some intent to act, without a specific plan) or Item 5 (active suicidalideation with a specific plan and intent) on the C-SSRS

3. Non-suicidal self-injurious behavior is not exclusionary

4. Any clinically significant abnormalities, including any finding(s) from ECG, orlaboratory test at Visit 6, and the physical examination, vital signs, at the EOTvisit of Study KAR-012 that the Investigator, in consultation with the MedicalMonitor are considered to jeopardize the safety of the subject

5. Female subject is pregnant

6. If, in the opinion of the Investigator (and/or Sponsor/ Medical Monitor), subject isunsuitable for enrollment in the study or subject has any finding that, in the viewof the Investigator (and/or Sponsor /Medical Monitor), may compromise the safety ofthe subject or affect their ability to adhere to the protocol visit schedule orstudy requirements

7. Risk of violent or destructive behavior as per Investigator's judgement

8. Subjects participating in another investigational drug or device trial or planningon participating in another clinical trial during the study

9. History or high risk of urinary retention, gastric retention, or narrow angleglaucoma as evaluated by the Investigator

10. Subject is taking, or plans to take while in the study, any prohibited concomitantmedication

11. For all male subjects only, any one of the following:

12. History of bladder stones

13. History of recurrent urinary tract infections

14. Serum prostate specific antigen (PSA) >10 ng/mL

15. An International Prostate Symptom Score (IPSS) of 5 (almost always) on eitheritem 1, 3, 5, or 6

16. A sum of scores on IPSS items 1, 3, 5, and 6 of ≥9 Note: IPSS will be requiredonly for male subjects ≥ 45 years of age. Subjects already enrolled in thestudy who do not have available PSA values from Study KAR-012 for baselinevalue use in Study CN012-0009, will have these assessments at their next clinicvisit planned after re-consenting to determine current eligibility.