A 2-Part Study to Assess Efficacy, Safety and Tolerability of BMB-101 for the Treatment of Patients With Prader-Willi Syndrome.

Inclusion Criteria: * Participant must be aged 18-65 years (both inclusive). * Genetically confirmed diagnosis of Prader Willi Syndrome via standard DNA testing or other commonly approved methods. * Willing and able to provide voluntary written informed consent, or have a Legally Authorized Representative who is able to provide consent. * Moderate to severe hyperphagia as defined by a HQ-CT score ≥ 13 at time of randomization (Visit 3). * If participant is receiving growth hormone, the subject must be on the same medication and stable dose for at least 90 days prior to Visit 1. * Female participant of childbearing potential must have a negative urine pregnancy test at baseline. Participants of childbearing or child-fathering potential must be willing to use medically acceptable forms of birth control, which includes abstinence, while in this study and for 90 days after the last dose of study drug. * Participant and/or caregiver has the ability to be compliant with study requirements, including visit schedule, diary completion and study drug accountability. * If a caregiver assists in completion of questionnaires, the same caregiver is available to complete the questionnaires throughout the duration of the study. Exclusion Criteria: * Participant has used metabolic agents known to affect appetite within 3 months of Visit 1. * Participant use of psychotropic medications including SSRIs/SNRIs, monoamine-oxidase inhibitors, tricyclic antidepressants, other serotonergic agonist…