Soleno Therapeutics has won US Food and Drug Administration (FDA) approval for diazoxide choline – which will be branded as Vykat XR – to treat extreme hunger in patients with Prader-Willi syndrome.
This approval follows a three-month delay from the FDA. In November 2024, the agency classified responses from Soleno as a “major amendment” to its new drug application (NDA), requiring additional time to review. However, the agency did not raise concerns about the drug’s safety, efficacy, or manufacturing.
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Prader-Willi syndrome is a rare genetic disorder caused by abnormalities in chromosome 15. Symptoms include low muscle tone, developmental delays, and behavioural challenges. Extreme hunger – known as hyperphagia, is one of the most serious and defining characteristics of the disorder and can lead to severe obesity and associated health complications if unmanaged. Vykat XR is now the only FDA-approved treatment specifically addressing hyperphagia in Prader-Willi syndrome.
The FDA approval of Vykat XR was based on data from the Phase III Study C602-RWP clinical trial (NCT03714373). Efficacy was demonstrated during a 16-week randomised withdrawal study period. Patients who switched to a placebo demonstrated a statistically significant worsening of hyperphagia compared to those who remained on Vykat XR.
The drug was also studied in the Phase III DESTINY-PWS trial (NCT03440814), which enrolled 127 individuals with genetically confirmed Prader-Willi syndrome. The trial did not demonstrate a statistically significant difference in hyperphagia reduction overall, but Soleno reported “nominally significant” reductions in fat mass, and general improvements in condition as assessed by investigators.
Vykat XR is set to launch in the US in April 2025, according to Soleno’s 26 March announcement. Vykat XR – an extended-release tablet containing a crystalline salt formulation of diazoxide – works by activating the adenosine triphosphate (ATP)-sensitive potassium (KATP) channel, which plays a role in hunger regulation.
The approval was welcomed by the Prader-Willi Syndrome Association: “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 of the Association.
Soleno also has its eyes set on Europe, having announced previously that it plans to file for approval of Vykat XR in the EU in the first half of 2025.
According to GlobalData’s Pharma Intelligence Center, Vykat XR is set to generate $876m in sales by 2030.
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