Study of Carbetocin Nasal Spray for the Treatment of Hyperphagia in Prader-Willi Syndrome

12-week, randomized, double-blind, placebo-controlled, parallel-group study of carbetocin nasal spray for the treatment of hyperphagia in Prader-Willi syndrome (PWS)

Inclusion Criteria * Male or female participants aged 5 to 30 years * Diagnosis of Prader-Willi syndrome with a documented disease-causing genetic mutation * Evidence of hyperphagia, including increased appetite and decreased satiety with food-seeking behaviors * Meeting minimum severity thresholds for hyperphagia based on validated clinical assessments at Screening and Baseline * Residing with a caregiver who is able and willing to comply with study procedures and participate in study visits Exclusion Criteria * Diagnosis of Schaaf-Yang syndrome or another genetic, hormonal, or chromosomal disorder other than Prader-Willi syndrome * Active upper respiratory infection at Screening or Baseline * Clinically significant medical conditions that could interfere with study participation or interpretation of results (e.g., cardiovascular, renal, hepatic, gastrointestinal, or respiratory disease) * History of significant neurological conditions (e.g., cerebrovascular disease, brain trauma, epilepsy, or frequent migraines), except for a history of febrile seizures * Recent or planned nasal surgery that could affect intranasal drug administration * Unwillingness to restrict use of intranasal medications that may interfere with study treatment * Recent clinically significant psychiatric instability, including irritability or agitation requiring changes in antipsychotic therapy * Use of medications or treatments that may interfere with the evaluation of hyperphagia or study endpoints within a defined period prior to Screening Active psychotic disorder or history of significant psychotic symptoms * History of suicide attempt or inpatient psychiatric hospitalization * Recent changes in food-related behavioral or environmental interventions that may confound assessment of hyperphagia Additional inclusion and exclusion criteria apply. Participants will be evaluated at Screening to ensure all eligibility requirements are met.