STAT reported on October 13 that patient advocates and some experts are expressing growing alarm about Vykat XR, Neurocrine Biosciences’s treatment for the insatiable hunger, or hyperphagia, of Prader-Willi syndrome. The drug has been linked in reports to regulators to the deaths of seven people and the hospitalization of nearly 100 others since its approval 18 months ago.
The limits of that evidence need stating plainly, because STAT states them too. The case reports, submitted to regulators and obtained by STAT through the Freedom of Information Act, do not prove causality. Many of the cases involved complex medical issues and multiple medications. The signal is nonetheless specific enough that some experts, in STAT’s reporting, judge the evidence sufficient to conclude the drug is causing unacceptable harm. That is an expert judgment reported by one outlet, not a regulatory finding, and this story is graded accordingly.
The background is two months old. In August, a group of Prader-Willi physicians and the major patient organizations, the Foundation for Prader-Willi Research, the International Prader-Willi Syndrome Organization and Prader-Willi Syndrome USA, issued a statement drawing attention to reports in the FDA’s adverse event system: seven deaths and more than 100 serious adverse events, mostly hospitalizations for swelling, respiratory and heart complications. The drug’s label already warns about fluid overload, based on edema seen in trials. The clinician statement itself said it cannot be determined from the reports whether the deaths and complications are related to treatment or to the underlying challenges of Prader-Willi syndrome.
Vykat XR, diazoxide choline, was approved in March 2025 and came to Neurocrine through its 2.9 billion dollar buyout of Soleno Therapeutics. It is the first drug approved for hyperphagia in this population, which is precisely why a safety dispute is hard to resolve quickly: there is no alternative therapy to switch to, and the untreated condition is itself dangerous. What to watch is procedural, not rhetorical: any FDA statement, label change, or company response to the October reporting. None was available in the sources reviewed for this edition.