In a landmark decision Wednesday, the U.S. Food and Drug
Administration approved Vykat XR, marking the first-ever treatment for the uncontrollable hunger experienced by individuals with Prader-Willi syndrome. The medication, developed by Soleno Therapeutics, is authorized for use in both adults and children aged four and above.
This approval represents a significant breakthrough in treating a condition that affects between 10,000 and 20,000 Americans.
Prader-Willi syndrome, characterized by various cognitive and behavioral symptoms, is most notably marked by an overwhelming hunger that can lead to dangerous binge eating behaviors. The condition often requires caregivers to implement strict security measures around food access to prevent health complications from excessive eating, including severe obesity and potential fatality.
Until now, treatment options have been limited to supportive care and human growth hormone therapy for managing muscle mass and 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 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 in treating 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. The company identified substantial differences in data collected before and after March 2020, while noting meaningful improvements in secondary measurements.
Working collaboratively with the FDA, Soleno developed an innovative solution to validate the drug’s effectiveness. They added a new component to their study where patients either continued or
discontinued Vykat treatment, measuring hyperphagia levels over time. This approach proved successful in September 2023, leading to the subsequent approval application.
The approval process reflected growing calls within the medical community for greater flexibility in reviewing treatments for Prader-Willi syndrome. In 2023, experts published an editorial in the International Journal of Molecular Sciences advocating for a more adaptable approach to drug approval in this area, similar to exceptions made for conditions like ALS and Alzheimer’s disease.
The market has responded positively to Soleno’s development efforts, with the company’s valuation exceeding $2 billion in anticipation of the approval. While a temporary delay in November caused some investor concern, market analysts remained optimistic due to the significant unmet medical need and the FDA’s prior endorsement of the study design.
Financial analysts at Stifel estimate the market potential for Vykat could exceed $1.5 billion annually, citing hyperphagia as the most significant burden for patients with Prader-Willi syndrome. They note substantial enthusiasm from both patients and healthcare providers for this new treatment option.
The approval marks a turning point in Prader-Willi syndrome research, where previous attempts at developing effective treatments have faced significant challenges. The condition’s complex genetics and varied manifestations have contributed to multiple Phase 3 trial failures and regulatory rejections over the past 25 years since the approval of human growth hormone therapy.
The medication’s list price has not yet been disclosed by Soleno Therapeutics, but the approval represents a major advancement in addressing one of the most challenging aspects of Prader-Willi syndrome, offering hope to patients and families affected by this rare genetic condition.