To evaluate long-term safety and tolerability of carbetocin nasal spray (3.2 mg TID) in subjects with PWS

This is a long-term, OLE study to evaluate long-term safety and tolerability of carbetocin nasal spray (3.2 mg TID) in subjects with PWS. Subjects who complete the antecedent double-blind study (ACP-101-302) will be invited to participate in the present study.

Inclusion Criteria:

• Has completed the Week12/EOT visit of the antecedent, Study ACP-101-302
• Met all entry criteria for the antecedent study
• May benefit from long-term treatment with open-label carbetocin in the judgment of the Investigator.
• Lives with a caregiver who understands and is willing and able to adhere to study-related procedures and is willing to participate in all study visits.

Exclusion Criteria:

• History of, or current, cerebrovascular disease, brain trauma, epilepsy, or frequent migraines. A history of febrile seizures is not exclusionary.
• Active psychotic symptoms, a history of psychotic symptoms, or a psychotic disorder
• History of suicide attempt or inpatient psychiatric hospitalization
• Has a clinically significant abnormality in vital signs at Baseline
• Has an average QTcF interval of >450 ms on the Baseline ECG performed before the first dose of carbetocin is given in the present study (i.e., the ECG performed at the EOT visit of the antecedent study)
• Has developed a clinically significant ECG finding during the antecedent study
• Subject is judged by the Investigator or the Medical Monitor to be inappropriate for the study due to AEs, medical condition, or noncompliance with investigational product or study procedures in the antecedent study

Additional inclusion/exclusion criteria apply. Subjects will be evaluated at screening to ensure that all criteria for study participation are met.