FDA Approves Soleno Therapeutics’ Vykat XR for Hyperphagia in Patients with Prader-Willi Syndrome

Image Credit: Adobe Stock Images/Yurii Kibalnik

The FDA has approved Soleno Therapeutics’ Vykat XR (diazoxide choline) extended-release tablets to treat hyperphagia in individuals aged four years and older with Prader-Willi syndrome (PWS). The approval, which marks the first in the United States for this indication, was based on efficacy results from the Phase III C602-RWP study.¹

“The approval of Vykat XR is a significant milestone for Soleno and, most importantly, for the PWS community who have had no options to treat the most disruptive aspect of this disease,” said Anish Bhatnagar, MD, CEO, Soleno, in a press release. “We are deeply grateful to the many individuals with PWS, their caregivers and clinical sites who participated in our trials, the advocacy groups, including [Foundation for Prader-Willi Research] and [Prader-Willi Syndrome Association USA], the advocates who have tirelessly supported the approval of Vykat XR, the FDA for a collaborative review process, and our employees who have been committed to delivering Vykat XR to those with PWS.”

The multi-center, randomized, double-blind, placebo-controlled C602-RWP study established the efficacy of Vykat XR during a withdrawal period that included 77 patients previously enrolled in Study C602. These patients had been on open-label treatment with Vykat XR between two and four years. Patients were randomly assigned in a 1:1 ratio to receive either Vykat XR or a placebo for four months.

The primary endpoint of the study was change from baseline in hyperphagia-related behaviors as assessed by the hyperphagia questionnaire for clinical trials (HQ-CT). Key secondary endpoints included investigator assessments of participants’ overall severity of illness and change in condition, as measured by Clinical Global Impression of Severity (CGI-S) and Clinical Global Impression of Improvement (CGI-I) ratings, respectively.

Patients who switched to placebo experienced a significant worsening of hyperphagia, with their HQ-CT total score increasing by 5.0 points from baseline at week 16. Additionally, CGI-S and CGI-I scores suggested a worsening trend in the placebo group (p=0.08 and 0.09, respectively), though these did not meet statistical significance.²

No new safety signals were identified in patients treated with Vykat XR. Common adverse events included hypertrichosis, edema, hyperglycemia and rash.¹

“The FDA approval of Vykat XR is an incredible achievement for the entire PWS community,” said Jennifer Miller, MD, professor of pediatric endocrinology, University of Florida, Gainesville, principal investigator of the Vykat XR clinical development program, in a press release. “I am excited to have Vykat XR available to help treat hyperphagia, which is the most life-limiting aspect of PWS. Families of people with PWS have been prisoners in their own homes because of the need to provide constant, eyes-on supervision 24/7 with access to food being completely restricted.”

According to Rare Disease Advisor, the estimated incidence of PWS is one out of every 10,000 to 30,000 live births. It effects anywhere from 350,000 and 400,000 people globally, with a global prevalence of one to nine per 100,000 people. It can also lead to obesity in early childhood due to hyperphagia.³

“Today marks a historic day for the PWS community. The FDA’s approval of Vykat XR represents a monumental step forward in addressing the longstanding unmet needs of individuals living with PWS and their families,” said Stacy Ward, CEO, Prader-Willi Syndrome Association USA, in the press release. “Our families experience the constant and disruptive challenges of hyperphagia, and Vykat XR offers hope to so many.”

Vykat XR is expected to launch in the United States next month.¹

References

1. Soleno Therapeutics Announces U.S. FDA Approval of VYKAT™ XR to Treat Hyperphagia in Prader-Willi Syndrome. Soleno Therapeutics. March 26, 2025. Accessed March 27, 2025. https://investors.soleno.life/news-releases/news-release-details/soleno-therapeutics-announces-us-fda-approval-vykattm-xr-treat

2. Soleno Therapeutics Announces Positive Statistically Significant Top-line Results from Randomized Withdrawal Period of Study C602 of DCCR for Prader-Willi Syndrome. Foundation for Prader-Willi Sndrome. September 26, 2023. Accessed March 27, 2025. https://www.fpwr.org/blog/soleno-therapeutics-announces-positive-statistically-significant-top-line-results-from-randomized-withdrawal-period-of-study-c602-of-dccr-for-prader-willi-syndrome

3. Prader-Willi Syndrome (PWS). Rare Disease Advisor. Accessed March 27, 2025. https://www.rarediseaseadvisor.com/disease-info-pages/prader-willi-syndrome-epidemiology/