Soleno Therapeutics has achieved a significant milestone in the treatment of a rare genetic disorder, announcing the publication of pivotal clinical study results for VYKAT™ XR in the prestigious Journal of Clinical Endocrinology and Metabolism. According to The Manilla Times, the publication marks another step in validating what is currently the first and only FDA-approved treatment specifically targeting hyperphagia, the hallmark and most debilitating symptom of Prader-Willi Syndrome (PWS).
The published research details findings from a 16-week randomized withdrawal study (C602-RWP) involving 77 participants who had previously completed earlier Phase 3 trials. In this controlled trial, participants were randomly assigned to either continue receiving VYKAT XR (diazoxide choline extended-release tablets) or switch to placebo. The results provided compelling evidence of the drug’s therapeutic necessity: when patients transitioned to placebo, hyperphagia symptoms worsened significantly compared to those who remained on active treatment.
The study measured hyperphagia severity using the Hyperphagia Questionnaire for Clinical Trials (HQ-CT), which served as the primary endpoint. Results showed statistically significant worsening in the placebo group compared to the VYKAT XR group, with a p-value of 0.0022. Beyond symptom questionnaires, the researchers observed tangible physical consequences: patients on placebo gained more weight and experienced greater increases in BMI z-scores than those continuing VYKAT XR treatment, underscoring the drug’s metabolic benefits.
The comprehensive Phase 3 clinical program supporting VYKAT XR’s FDA approval involved 127 participants with over 400 patient-years of drug exposure, including individuals with nearly six years of continuous treatment. This extensive data collection period provided robust safety and efficacy information for regulatory decision-making.
According to Dr. Jennifer Miller, lead author and a Pediatric Endocrinology professor at the University of Florida, the randomized withdrawal study’s results reinforce the meaningful and sustained benefits of VYKAT XR in managing this previously untreated condition. The symptom improvements extended beyond questionnaire scores; secondary endpoints including Clinical Global Impression measures, though not reaching statistical significance, also favored the active treatment group.
Safety data remained favorable throughout the trial, with adverse events occurring at similar rates in both treatment arms. Notably, no serious adverse events were reported in the VYKAT XR group, and no participant discontinued the study drug due to adverse effects.
Prader-Willi Syndrome is a rare genetic neurodevelopmental disorder affecting approximately one in every 15,000 live births. Hyperphagia in PWS manifests as a chronic, life-threatening condition characterized by constant hunger sensation, persistent food preoccupation, compulsive eating behavior, and absent satiety signals. Without proper management, this symptom can lead to immediate dangers such as stomach rupture or choking, and long-term complications including obesity, diabetes, and cardiovascular disease.
The FDA approved VYKAT XR on March 26, 2025, for treating hyperphagia in adults and pediatric patients 4 years and older with PWS. The successful publication in JCEM, one of the world’s leading peer-reviewed journals specializing in endocrine and metabolic research, provides additional scientific validation for clinicians considering this treatment option and offers families affected by PWS evidence-based hope for managing this previously untreated symptom.
