Soleno Therapeutics presents data on VYKAT XR for Prader-Willi syndrome at ENDO 2026. Soleno Therapeutics, a Neurocrine Biosciences company, announced on June 15 new late-breaking data at ENDO 2026 showing that resuming treatment with VYKAT XR (diazoxide choline) extended-release tablets for two years after a 16-week randomized withdrawal period was associated with durable improvements in hyperphagia and behavioral symptoms in individuals with Prader-Willi syndrome. Sanjay Keswani, M.D., Chief Medical Officer of Neurocrine Biosciences, said, "These compelling data further reinforce our confidence in VYKAT XR as a safe and effective long-term treatment for hyperphagia in individuals four years of age and older living with Prader-Willi syndrome. Individuals who resumed treatment following the randomized withdrawal period achieved durable improvements in hyperphagia and other PWS-related behaviors. This completes the presentation of data from our comprehensive Phase 3 development program and further confirms the long-term benefit of VYKAT XR for people living with PWS." The Phase 3 development program included Study C614, an open-label long-term extension study enrolling 77 participants. The study assessed whether those who had received placebo during the withdrawal period could regain benefit after restarting VYKAT XR and whether those who remained on continuous therapy maintained improvement over time. Hyperphagia was measured using the Hyperphagia Questionnaire for Clinical Trials (HQ-CT), while behavioral symptoms were assessed by the PWS Profile questionnaire (PWSP). Results showed that participants resuming VYKAT XR experienced recovery of benefit, while those continuing therapy maintained improvements. Additional presentations compared outcomes from VYKAT XR-treated participants to natural history controls from the PATH for PWS Natural History Study. Over three years, statistically significant and sustained improvements were observed in hyperphagia scores at all evaluated time points (p<0.0001), with consistent benefits also reported across six behavioral domains such as anxiety, rigidity/irritability, compulsivity, aggressive behaviors, disordered thinking, and depression. Prader-Willi syndrome is described as a rare genetic neurodevelopmental disorder caused by abnormal gene expression on chromosome 15. The main symptom is hyperphagia - a persistent sensation of hunger leading to food preoccupations - which can severely affect quality of life and lead to additional health complications including diabetes or cardiovascular disease. VYKAT XR was approved by the U.S. Food and Drug Administration on March 26, 2025, for treating hyperphagia in adults and pediatric patients aged four years or older with Prader-Willi syndrome. Important safety information includes contraindications related to hypersensitivity to diazoxide or thiazides; warnings about risks such as hyperglycemia or fluid overload; monitoring recommendations; and common adverse reactions like hypertrichosis or edema.