The United States Food and Drug Administration has approved the first medication designed to treat the extreme hunger associated with Prader-Willi syndrome, marking a significant breakthrough in the treatment of this rare genetic disorder.
Soleno Therapeutics’ Vykat XR received regulatory clearance on Wednesday for use in both adults and children aged four and above who experience hyperphagia, the intense and uncontrollable hunger that characterizes Prader-Willi syndrome. The company has not yet revealed the medication’s pricing structure.
This approval represents a crucial development in addressing a condition that affects between 10,000 and 20,000 Americans.
Prader-Willi syndrome manifests through various cognitive and behavioral symptoms, with the most severe being an overwhelming hunger that often requires caregivers to implement security measures to prevent patients from accessing food. The condition can lead to dangerous binge eating, severe obesity, metabolic complications, and in some cases, death.
Until now, treatment options have been limited to supportive care measures and human growth hormone therapy, which helps increase muscle mass and reduce body fat. While some physicians have prescribed the anti-seizure drug topiramate off-label to help control appetite, no medications had been specifically approved for treating the syndrome’s characteristic hyperphagia.
The path to Vykat’s approval was unconventional. The drug, previously known as DCCR, is an extended-release version of diazoxide, a compound used to treat low blood sugar. Despite failing to meet its primary endpoint in a Phase 3 trial five years ago, Soleno argued that the COVID-19 pandemic had significantly impacted the study results, pointing to marked differences in data collected before and after March 2020.
In response, Soleno worked with the FDA to develop an innovative solution. They added a new component to the study where patients either continued or discontinued Vykat treatment, measuring
hyperphagia levels over time. This approach proved successful in September 2023, leading to the submission of an approval application.
The approval process for Prader-Willi treatments has historically been challenging, prompting experts to advocate for greater regulatory flexibility. In a 2023 editorial published in the International Journal of Molecular Sciences, researchers drew parallels to FDA approvals for conditions like ALS and Alzheimer’s disease, arguing that similar considerations should apply to Prader-Willi syndrome.
Since announcing positive results, Soleno’s market capitalization has exceeded $2 billion, though a delayed regulatory decision in November 2024 temporarily raised investor concerns. Financial analysts have remained optimistic about the drug’s prospects, with Stifel estimating an annual market potential exceeding $1.5 billion. The absence of approved treatments for hyperphagia and strong interest from both patients and healthcare providers have contributed to positive market expectations.
Baird analyst Brian Skorney noted in February that despite the unusual nature of the approval application, the combination of compelling evidence and significant unmet medical need positioned Soleno favorably for regulatory success.
This approval marks the first significant advancement in Prader-Willi syndrome treatment since the authorization of human growth hormone therapy 25 years ago. Previous attempts to develop effective treatments have faced numerous setbacks, with multiple drug candidates either failing in late-stage clinical trials or being rejected by regulators, highlighting the complexity of addressing this
multifaceted genetic disorder.