PWS advocacy groups share safety guidance on approved treatment
Statement addresses potential risks of Vykat XR for treating excessive hunger
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A trio of advocacy groups have come together to help families understand safety risks associated with Vykat XR (diazoxide choline), an oral treatment approved to ease hyperphagia, or excessive hunger, in people with Prader-Willi syndrome (PWS).
In light of new safety data reported since Vykat XR became commercially available, the three groups — Prader-Willi Syndrome Association USA (PWSA | USA), the Foundation for Prader-Willi Research (FPWR), and the International Prader-Willi Syndrome Organisation — have jointly put out a statement offering guidance on the use of this medication for caregivers of people with PWS.
“VYKAT XR represents an important advancement in the treatment of hyperphagia,” Stacy Ward, CEO of PWSA | USA, wrote in an association blog post. “Our goal is to ensure that families and clinicians have the resources they need to use this tool thoughtfully, safely, and effectively, always keeping the person with PWS at the center of every decision.”
In a separate blog post, the FPWR said that this statement intends “to support healthcare providers and families in making informed treatment decisions, recognizing potential medical concerns early, and promoting the safe use of VYKAT XR through appropriate monitoring and ongoing communication between families and their healthcare team.”
Deaths, health complications reported since approval of Vykat XR
PWS is a genetic condition with a range of developmental and behavioral symptoms, including hyperphagia, which typically leads to obesity.
Vykat XR is an oral medication that works by modulating the activity of ATP-sensitive potassium (KATP) channels, which are proteins that help control how brain cells release certain signaling molecules. By altering KATP channel activity, the therapy is expected to reduce the amount of hunger-stimulating signaling molecules that are thought to contribute to hyperphagia.
Clinical trials have shown that Vykat XR can help ease hyperphagia in people with PWS. But like any medication, Vykat XR can cause side effects. KATP channels are also present in other cells in the body, including in the heart, pancreas, and muscle, so their activation may result in unwanted effects.
In clinical trials, the most commonly reported side effects of Vykat XR were rash, excessive hair growth, high blood sugar, and swelling. No deaths were reported.
Based on these reports alone, it is not possible to say for certain whether these deaths were related to use of the drug or were part of the health challenges that come with PWS.
However, since the therapy’s U.S. approval in 2025 to reduce hyperphagia in adults and children with PWS, ages 4 years and older, seven deaths have been reported in patients taking this medication. There have also been more than a hundred reported instances of serious health complications.
Almost all of these events were related to difficulty breathing and/or heart problems. Notably, most of the affected patients had complex underlying health conditions and were taking other medications in addition to Vykat XR.
The new statement aims to put these reports in context so that caregivers can fully understand the potential risks. The associations stress that because these patients had complex underlying issues and PWS itself is associated with increased mortality risk, it’s not clear if any of these events were directly caused by Vykat XR.
“Based on these reports alone, it is not possible to say for certain whether these deaths were related to use of the drug or were part of the health challenges that come with PWS,” the statement reads.
Statement urges careful patient selection and close monitoring
The statement also notes that clinical trials testing Vykat XR were by necessity small, given that PWS is a rare disease. And for ethical reasons, trials testing experimental medications generally don’t enroll participants with many underlying health problems.
“As a result, when a new drug is approved, doctors may not know exactly what to expect in patients who have more medical problems and other complications,” the statement says. “That is why doctors need to be careful when using new medicines in patients with more complicated medical problems.”
The associations emphasized that “the purpose of this new statement is not to discourage the use of VYKAT XR” but, as Ward says in her statement, “to encourage informed prescribing, careful patient selection, and close monitoring, particularly for individuals with known risk factors.”
These factors include:
- severe obesity
- a history of or current heart or breathing problems
- a history of severe lung infections
- swelling or fluid buildup in the body,
- uncontrolled sleep apnea, a condition where breathing is repeatedly interrupted during sleep)
The statement advises caregivers to be in touch with a doctor who knows PWS well and can help them individually understand the potential risks in their specific situation. Caregivers are also encouraged to read recently published guidelines on the use of Vykat XR in PWS.
In combination with the statement aimed at caregivers, which is written in lay-friendly language, the advocacy organizations have also issued a more technical statement aimed at clinicians, and republished a FAQ for parents.
“We encourage families, clinicians, residential providers, and care teams to review and share both resources,” Ward wrote. “Better information leads to better conversations, better decisions, and ultimately better care for people living with PWS.”
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