"Since 2000, when the FDA approved recombinant human growth hormone (rhGH) for those with the rare genetic disorder Prader-Willi Syndrome (PWS), several companies have come up short in their attempts to develop a more advanced treatment for hyperphagia, an insatiable hunger condition associated with PWS.
Wednesday, Soleno Therapeutics broke through with an FDA nod for Vykat XR (diazoxide choline), which becomes the first drug to treat hyperphagia. It is endorsed for those aged 4 years and older with the condition, which leaves patients with low muscle tone, short stature and intellectual and developmental problems.
The once-daily extended-release tablet is a potassium channel activator. The channels, which are widespread throughout the body, including in the pancreas, regulate insulin secretion. With the approval, the share price of the 26-year-old Redwood, California, company had soared by 37% on Thursday morning.
Based on the average weight of patients in its clinical trials, Soleno will charge $466,200 per year for Vykat XR. The company expects it to be available next month.
In a release, Soleno CEO Anish Bhatnagar, M.D., called the approval “a significant milestone” for the company and for the “PWS community who have had no options to treat the most disruptive aspect of this disease.”
Jennifer Miller, M.D., of the University of Florida and a principal investigator in the Vykat XR’s clinical development program, added that it will help families of those with PWS who “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.”
The approvel was backed by a phase 3 trial in which patients were observed during a 16-week withdrawal study after receiving Vykat XR for a median period of 3.3 years. Those who switched to placebo for the study period demonstrated a statistically significant worsening of hyperphagia compared to patients who remained on the drug.
Over four years of data collected in four open-label studies, Vykat XR has shown a consistent safety profile with the most common adverse reactions—hypertrichosis, edema, hyperglycemia and rash—occurring in roughly 10% of the patients. The Prader-Willi Syndrome Association USA estimates that the disorder occurs in 1 in every 15,000 live births, with more than 300,000 people worldwide affected. Soleno says that claims data show there are 10,000 PWS patients in the U.S.
Among the companies that have struck out in their attempts to develop a treatment for hyperphagia are Alize Pharma of France, which succeeded in a 2016 phase 2 study with AZP-531, a first-in-class unacylated ghrelin peptide analog, but failed to progress it further.
In 2016, Boston-based Zafgen demonstrated the efficacy of beloranib, a MetAP2 inhibitor, in a phase 3 trial before the treatment was derailed by safety issues.
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Sweden’s Saniona developed Tesomet, a combination of monoamine reuptake inhibitor tesofensine and beta blocker metoprolol, which gained Orphan Drug designation from the FDA in 2021 before its development was halted a year later because of funding limitations.
Acadia Pharmaceuticals of San Diego is developing a treatment, intranasal carbetocin, which the FDA rejected in 2022. Acadia gained the candidate through a $10 million acquisition of Chicago’s Levo Therapeutics.