Soleno’s Vykat XR is the first drug approved for the rare disease that directly targets its hallmark symptom.
The FDA signed off on Soleno Therapeutics’ treatment for a major symptom of the rare disease Prader-Willi syndrome. The drug, diazoxide choline extended-release tablet, will now carry the brand name Vykat XR.
Vykat XR is specifically indicated to address hyperphagia, or the abnormally strong sensation of hunger, which often leads to excessive eating. Its approval covers both adult and pediatric patients with Prader-Willi syndrome (PWS) aged 4 years and up. Soleno is working to make the drug available in the U.S. next month, as per its Wednesday release.
Vykat XR is the first drug that targets hyperphagia in PWS.
In a note to investors, Stifel analysts called the approval “a significant win” for Soleno, pointing to Vykat XR’s “very favorable/clean” label, the lack of a boxed warning or exclusions according to the severity of hyperphagia. “We think the drug’s well-positioned to launch strongly into what we see as a blockbuster opportunity.”
PWS is a rare and genetic neurodevelopmental disorder that affects one in every 15,000 live births. Hyperphagia is the “defining symptom” of PWS, according to Soleno, pointing to the “extreme drive to consume food” that not only compromises quality of life for patients and their families but can also become life-threatening without treatment.
Vykat XR’s active ingredient is diazoxide, a molecule that has been used “for decades” to manage rare diseases in infants, though never for PWS, according to a June 2024 news release from Soleno. To assess the drug’s potential in PWS, the biotech ran a Phase III clinical program of diazoxide consisting of two trials: C601, a randomized, double-blinded and placebo-controlled study, and C602, an open-label extension study.
Soleno presented long-term data from these studies in June 2022, touting significant improvements in metabolic parameters, showing that the drug could tamp down on hyperphagia. At the one-year follow-up, patients had significantly better lean body mass, fasting insulin and leptin levels, insulin sensitivity and adiponectin, a cardioprotective marker.
Vykat XR’s approval continues biopharma’s rally in the rare disease space. Last week, for instance, Novartis’ factor B inhibitor Fabhalta won the FDA’s go-ahead for C3 glomerulopathy to lower proteinuria, becoming the first-ever drug for the indication. And last month, Mirum notched a nod for Ctelix for use in cerebrotendinous xanthomatosis—also an industry first.
Similarly, the FDA in February signed off on SpringWorks’ rare disease drug Gomekli, which can now be used for adults and children with neurofibromatosis type 1 with symptomatic plexiform neurofibromas.
