Neurocrine Biosciences’ newly approved Prader-Willi syndrome drug Vykat XR is facing serious scrutiny after a group of physicians and experts notified clinicians of patient deaths and severe adverse events potentially linked to treatment. The statement cites FDA Adverse Event Monitoring System data showing seven deaths among patients prescribed Vykat XR and more than 100 reports of serious events, including hospitalizations for swelling, respiratory, and heart complications. FDA previously approved Vykat XR in March 2025 to curb intense hunger in children and adults with Prader-Willi syndrome. The clinicians’ note emphasizes that neither the deaths nor the severe side effects have been definitively linked to the drug, while urging heightened awareness when initiating therapy. For clinicians and regulators, the development turns a first-in-class rare-disease approval into a real-time safety question—raising pressure for clearer risk characterization, patient selection, and monitoring protocols as the drug is used more broadly.