Prader-Willi Syndrome (PWS) Clinical Trials and Treatments

Prader-Willi Syndrome results from loss of function of paternal genes on chromosome 15, either through deletion, maternal uniparental disomy, or imprinting defects. In infancy, affected individuals typically present with poor muscle tone, weak cry, and feeding difficulties that may require specialized feeding techniques. Between ages 1 and 6, a dramatic change occurs, with development of hyperphagia, an insatiable appetite and obsession with food.

The most common symptoms of Prader-Willi Syndrome include Poor muscle tone (hypotonia) in infancy, Weak cry and poor feeding in newborns, Excessive hunger and rapid weight gain in childhood, Short stature and slow growth, Underdeveloped sexual organs and incomplete sexual development, among others. Approximately 1 in 10,000 to 30,000 live births. Symptoms can range from mild to severe and may vary between individuals.

Trial Friend lists all active clinical trials for Prader-Willi Syndrome from ClinicalTrials.gov, with eligibility criteria translated into plain English. Patients can filter by trial phase and recruitment status, search by location, and use the Match Me tool to score trials against their profile. Trials in Prader-Willi Syndrome are testing more ways to ease hyperphagia beyond Vykat XR (diazoxide choline), along with treatments for sleepiness, behavior and weight. Open studies on ClinicalTrials.gov include Harmony Biosciences' Phase 3 trials of pitolisant for excessive daytime sleepiness (NCT06366464), a Phase 2 trial of BMB-101 for hyperphagia (NCT07266324), early studies of setmelanotide (NCT06772597) and CSTI-500 (NCT07348601), tirzepatide for weight (NCT06901245), and non-drug approaches such as vagus nerve stimulation for temper outbursts (NCT06144645).

Yes. As of October 21, 2026, 2 FDA-approved medicines have a current label that names Prader-Willi Syndrome: Vykat XR (diazoxide choline), first approved in 2025; and Genotropin (somatropin). Corticosteroids and immune globulins count once each.

Prader-Willi Syndrome is caused by a change in chromosome structure or number rather than a single gene. Caused by loss of paternal gene expression at 15q11-q13: about 70% paternal deletion, 25% maternal uniparental disomy, rarely an imprinting defect. DNA methylation testing detects nearly all cases; no single gene is sequenced. Most cases arise from a new variant not carried by either parent, so the chance of it recurring in a sibling is low but not zero. Approximately 1 in 10,000 to 30,000 live births.

Yes. Prader-Willi Syndrome is a chromosomal condition rather than a single-gene one, so the test is a chromosomal microarray, FISH, karyotype or DNA methylation study, depending on the change, not gene sequencing. Caused by loss of paternal gene expression at 15q11-q13: about 70% paternal deletion, 25% maternal uniparental disomy, rarely an imprinting defect. DNA methylation testing detects nearly all cases; no single gene is sequenced.

Most cases arise from a new variant not carried by either parent, so the chance of it recurring in a sibling is low but not zero.

The labs currently offering the test are listed in the Genetic Testing section of this page, pulled live from the NIH Genetic Testing Registry. A genetic counselor can help interpret the result and decide which relatives should be tested.

Eligibility for Prader-Willi Syndrome clinical trials depends on factors like age, diagnosis, treatment history, and overall health. Each trial sets its own inclusion and exclusion criteria. Trial Friend translates these requirements from medical language into plain English so patients can review them more easily. The Match Me tool can score your profile against active trials to help identify studies that may be a fit.

Participating in a Prader-Willi Syndrome clinical trial typically involves scheduled visits, medical tests, and close monitoring by a research team. Depending on the study phase, you may receive an investigational treatment, a placebo, or the current standard of care. Trials may last from a few weeks to several years. Study participation is voluntary, and you can withdraw at any time.