The purpose of this study is to learn more about how octreotide (Sandostatin LAR® Depot) affects levels of ghrelin, hunger, and body weight in people with Prader-Willi Syndrome.

After baseline tests, a nurse will administer monthly injections of Sandostatin LAR® or placebo for 6 months. At the end of this initial 6-month treatment period and a 4-month washout period, study subjects will then crossover to receive the alternative therapy (placebo or octreotide) for an additional 6 months. Subjects will be followed for 16 months total at scheduled visits: 0, 2, 6, 10, 12, and 16 months (Table 2).

Inclusion Criteria:

• o Diagnosis of PWS confirmed by chromosome analysis (i.e. interstitial deletion of paternally-derived chromosome 15Q, uniparental maternal disomy or other chromosome 15 abnormalities)

  • Age 18 years and older
  • Written informed consent obtained (by subject or guardian) and willingness to comply with the study schedule and procedures
  • Free T4, TSH values in the normal range (with or without thyroxine replacement)
  • Subjects with confirmed hypogonadism who are corrected with adequate doses of sex steroid replacement, will have been treated for at least 6 months prior to entry and have no change in dosages over the study period.
  • Patients with confirmed growth hormone deficiency who are corrected with adequate doses of replacement, will have been treated for at least 6 months prior to entry and have no change in dosages over the study period.

Exclusion Criteria:

• Symptomatic gallstones.
• Smokers.
• Alcohol consumption > 2 drinks per day.
• Exercise > 30 minutes 3 times a week.
• Weight > 500 lbs (exceeds the limit for the BODPOD).
• Active pulmonary infection.
• Sleep disorder.
• Subjects will be excluded if they have clinically significant disease that would have an impact on metabolic outcomes or body composition including diabetes mellitus, chronic inflammatory bowel disease, chronic severe liver or kidney disease, heart disease, cancer, symptomatic gallstones, or neurological disorders
• history of hepatic disease (patients with minimal, i.e., <3Xs the upper limit of normal for LFTs indicative of hepatic steatosis, MAY participate)
• pregnant or lactating
• known hypersensitivity to Sandostatin acetate or other related drug or compound
• subjects who exhibit symptoms indicative of intolerance following the 100 mcg test dose of Sandostatin Injection, SC
• subjects who have previously received Sandostatin® (octreotide)
• subjects who have received other investigational drugs administered or received within 30 days of study entry