A Study to Assess RAD011 (Cannabidiol Oral Solution) for the Treatment of Participants With Prader-Willi Syndrome

Inclusion Criteria:

• Males and females between 8 and 65 years of age (inclusive) at Screening.
• Genetically confirmed diagnosis of PWS. Documentation of genetically confirmeddiagnosis of PWS is acceptable.
• The same caregiver is available to complete the questionnaire throughout the durationof the study.
• After completion of the Tolerability period, participants will have a mean HyperphagiaQuestionnaire for Clinical Trials (HQ-CT) score ≥13 and a decrease of HQ-CT score nomore than 7 during Tolerability (run-in) period.
• If receiving growth hormone, psychotropic therapy, metabolic treatments that couldaffect appetite (including metformin), and other treatment including thyroid hormone,must be on the same medication and dose for at least 90 days prior to consent/assent

Exclusion Criteria:

• Known use of cannabis or cannabinoid containing products (including topical products)within 90 days prior to consent/ assent.
• Use of prescription or over-the-counter weight loss agents within 90 days prior toconsent/assent.
• Implementation of new food or environmental restrictions within 90 days of consent/assent.
• If living in a group home, participant spends less than 25 waking hours with theircaregiver per week.
• Uncontrolled chronic conditions (diabetes, sleep apnea, etc.) as determined by theInvestigator.