The U.S. Food and Drug Administration has reached a landmark decision in approving the first-ever treatment for the uncontrollable hunger associated with Prader-Willi syndrome. The medication, Vykat XR, developed by Soleno Therapeutics, received regulatory clearance on Wednesday for patients aged four and older.
This approval represents a significant breakthrough in addressing a rare condition that affects between 10,000 and 20,000 Americans. Prader-Willi syndrome manifests through various cognitive and behavioral symptoms, with its most severe characteristic 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 episodes, severe obesity, and metabolic complications that can be fatal.
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 the condition’s hyperphagia symptoms.
The journey to Vykat’s approval has been 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 Phase 3 trials 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.
Working collaboratively with the FDA, Soleno devised an innovative solution by adding a new component to the study. This addition involved randomly assigning patients to either continue or discontinue Vykat treatment, then measuring their hyperphagia levels over time. The company announced positive results from this modified approach in September 2023, leading to their regulatory submission.
The approval follows a 2023 editorial in the International Journal of Molecular Sciences, where experts advocated for greater regulatory flexibility in reviewing Prader-Willi treatments. They drew parallels to the FDA’s approach with other serious conditions like ALS and Alzheimer’s disease, where some regulatory concessions have been made due to the critical need for treatments.
The market has responded enthusiastically to Soleno’s progress, with the company’s valuation exceeding $2 billion in anticipation of the approval, despite some investor uncertainty following a delayed decision in November. Financial analysts at Stifel estimate the market potential for Vykat could surpass $1.5 billion annually, citing the significant impact of hyperphagia on patients and strong interest from both the medical community and patients.
This approval marks the first major advancement in Prader-Willi syndrome treatment since human growth hormone was cleared 25 years ago. The condition’s complex genetics and varied manifestations have historically challenged drug developers, with numerous Phase 3 candidates either failing or facing regulatory rejection. Industry analysts have noted that while Soleno’s approval pathway was not typical, the combination of compelling evidence and urgent medical need supported the positive outcome.
The price point for Vykat XR has not yet been disclosed by Soleno Therapeutics. The medication’s approval offers new hope for patients and families affected by Prader-Willi syndrome, who have long awaited an FDA-approved option for managing the condition’s most challenging symptom.