The purpose of this study is to evaluate the effect of rimonabant, a cannabinoid receptor-1
blocking drug, on the appetite, body weight, body fat and growth hormone level of subjects
with Prader-Willi Syndrome (PWS). This will be a double blind placebo controlled clinical
trial involving a total of 18 young adults aged 18 to 35 years with PWS. Patients will be
divided in to the two groups of control and intervention, and treated with either placebo
(inactive drug), or rimonabant 20 mg once a day for a total duration of 6 months. Body
weight, fat distribution, objective and subjective assessment of the hunger, fasting blood
sample for measurement of ghrelin and leptin (two hormones regulating appetite), serum
lipids , IGF-1(growth hormone related protein), insulin and glucose concentrations will be
measured upon enrollment, at 3 months, and at the end of the study. The proportion of body
fat to muscle will be determined using a radiological technique, whole body dual-energy
x-ray absorptiometry (DEXA) scan, and also by measurement of skin fold thickness, waist and
hip circumference at the enrollment prior to the intervention, and at the end of the study.
1. Subjects will be selected if they have Prader Willi Syndrome previously confirmed by
standard genetic testing (the DNA methylation test) or meet the clinical diagnostic
criteria as follows :the presence of at least four of the six principal
characteristics of PWS syndrome including 1) infantile hypotonia, 2) abnormal
pubertal development, 3) obesity after early infancy, 4) dysfunctional central
nervous system performance, 5) dysmorphic facial features, and 6) short stature. In
addition, they must have one or more of the following characteristics commonly
associated with PWS: 1) small hands and feet, 2) skin problems, 3) behavioral
problems related to food, and 4) decreased pain sensitivity.
2. Subjects must be 18 to 35 years of age and fairly cooperative with the study
3. Subjects must have a BMI of at least 30 or more.
1. Presence of pulmonary disease.
2. Presence of any other abnormal endocrine findings, including abnormal thyroid
3. Presence of significant behavioral problems or psychiatric illness including anxiety
disorder and depression, interfering with the follow up of protocol. Any degree of
depression and moderate to severe anxiety will be exclusion criteria for this study.
4. Subjects with Prader Willi Syndrome who are on other medications including growth
hormone therapy, anti epileptic medications, or antipsychotic medications.
5. The presence of moderate to severe renal or liver disease. Mild elevations of liver
enzymes are not exclusive.
6. Subjects who are on any other research or weight loss medication