n a major milestone for the Prader-Willi syndrome (PWS) community, the U.S. Food and Drug Administration has granted approval to Soleno Therapeutics for its new medication, Vykat XR, the first treatment specifically aimed at managing hyperphagia—an overwhelming and persistent sensation of hunger that is the most distressing hallmark of the condition.
Prader-Willi syndrome is a rare and complex genetic disorder, affecting an estimated 50,000 individuals in the United States. It results from a dysfunction on chromosome 15 that disrupts gene expression and regulation. One of its most devastating symptoms, hyperphagia, typically emerges in early childhood and intensifies with age. Unlike ordinary hunger, hyperphagia in PWS is chronic, unrelenting, and unresponsive to eating—placing individuals at constant risk for life-threatening obesity and its complications, including diabetes, cardiovascular disease, and respiratory issues.
Infants with PWS often begin life with weak muscle tone and feeding difficulties. But by age four to eight, a dangerous shift occurs: an insatiable appetite takes over. Caregivers must maintain strict food security, and behavioral challenges related to food-seeking can become a daily struggle. Some patients describe the experience as a feeling of starvation that never goes away, regardless of how much they eat.
With the launch of Vykat XR expected in April 2025, Soleno will offer the once-daily oral medication to patients aged four and older diagnosed with PWS and hyperphagia. Pricing will average around $466,200 per year, adjusted for patient weight.
How Vykat XR Works
Vykat XR operates by targeting neural pathways linked to hunger regulation. It reduces the secretion of a peptide in the brain that plays a key role in appetite signaling. In long-term follow-up studies, patients who remained on treatment saw a significant and sustained reduction in hyperphagia symptoms after one year—offering hope where previously, no FDA-approved therapies existed.
Navigating a Difficult Path to Approval
The road to regulatory approval wasn’t without setbacks. A pivotal phase 3 clinical trial involving 127 patients yielded mixed results—while those with more severe hyperphagia showed improvement, the study overall did not reach statistical significance compared to placebo. However, a separate randomized withdrawal study, along with long-term patient data, helped support the case for the drug’s effectiveness and safety.
Dr. Jennifer Miller, a pediatric endocrinologist at the University of Florida and a lead investigator in the Vykat XR trials, emphasized the profound impact of hyperphagia on patients’ lives. “One of my patients once told me, ‘Imagine the hungriest you’ve ever been. That’s how I feel all the time.’ That was the moment I knew I had to dedicate my work to this population,” she said.
Global Implications and Future Access
While Vykat XR is currently approved only in the U.S., efforts are already underway to bring the treatment to patients worldwide. Anthony Holland, president of the International Prader-Willi Syndrome Organisation (IPWSO), confirmed that the organization will collaborate with global health authorities to improve access and awareness.
For families and individuals living with PWS, this approval marks not just a new drug on the market—but a turning point in how the condition is treated, understood, and supported. As 21-year-old Justice Faith, a young woman with PWS, shared ahead of the decision: “Every person’s experience with hyperphagia is different, but knowing there may finally be a treatment makes me feel seen.”