A Study of GLWL-01 in Patients With Prader-Willi Syndrome

Participants will be assigned to one of two treatment sequences (GLWL-01/Placebo or
Placebo/GLWL-01), with each sequence consisting of two treatment periods separated by a
washout period

Inclusion Criteria:

- Confirmed diagnosis of PWS based on genetic confirmation using DNA method

- Body mass index (BMI) of 27 to 60 kg/m2

- No evidence of weight excursion beyond 10% of baseline weight

- Patients must provide assent and have a reliable caregiver (must have been caring for
the patient for at least 6 months) who provides a separate written informed consent to
participate. The caregiver is expected to be the primary caregiver throughout the
study and must be in frequent contact with the patient (defined as at least 4 awake
hours per day). The caregiver must be able to communicate with site personnel and in
the investigator's opinion must have adequate literacy to complete questionnaires. If
a caregiver cannot continue, 1 caregiver replacement is allowed

- Are on a stable diet and exercise regimen for >2 months prior

Exclusion Criteria:

- Current enrollment in or discontinuation within the last 30 days from a clinical trial
involving any investigational drug or device

- Are currently living in a group home for more than 50% of the time

- A history or presence of other medical illness that indicates a medical problem that
would preclude study participation

- Have an estimated glomerular filtration rate <60 mL/minute/1.73 m2. Have
macroalbuminuria (defined as spot urine albumin to creatinine ratio of >300 μg/mg) or
hematuria

- Are hypertensive (defined as sitting systolic blood pressure (BP) greater than or
equal to (≥)140 millimeters of mercury (mmHg) and diastolic BP ≥90 mmHg)

- Patients on weight loss medications within 30 days of dosing, or with a history of
bariatric surgery

- Unable to refrain from or anticipates the use of:

1. Any drugs known to be significant inhibitors of cytochrome P450 (CYP)3A enzymes
and/or P-glycoprotein (P-gp) including regular consumption of grapefruit or
grapefruit juice for 14 days prior to the first dose. Acetaminophen (up to 2
grams per 24-hour period) may be permitted

2. Any drugs known to be significant inducers of CYP3A enzymes and/or P-gp,
including St. John's Wort

3. Any medications that prolong the QT/QTc interval, unless the participant has been
stable on the medication for at least 3 months and has a corrected QT interval
(QTc) <450 msec

- Currently taking simvastatin >10 mg per day, atorvastatin >20 mg per day, or
lovastatin >20 mg per day, or have a history of statin-induced myopathy/rhabdomyolysis

- Unsuitable for inclusion in the study in the opinion of the investigator