Soleno secures FDA approval for Prader-Willi syndrome drug Vykat XR

The FDA has recently approved Vykat XR (diazoxide choline), marking a significant advancement in the treatment of hyperphagia associated with Prader-Willi Syndrome (PWS). This approval is noteworthy as it represents the first treatment specifically targeting hyperphagia, a condition causing excessive hunger in individuals with PWS, a rare genetic disorder. Vykat XR is recommended for patients aged four years and older, who often experience symptoms such as low muscle tone, short stature, and intellectual and developmental challenges.

Vykat XR is an extended-release tablet that functions as a potassium channel activator. These channels play a crucial role in regulating insulin secretion throughout the body, including the pancreas. Soleno Therapeutics, the company behind Vykat XR, has seen a significant increase in its share price following the approval, reflecting the importance of this development. The company plans to charge an annual fee of $466,200 for the drug, based on the average weight of patients in clinical trials, and anticipates its availability next month.

Anish Bhatnagar, M.D., CEO of Soleno Therapeutics, hailed the approval as a major milestone for both the company and the PWS community, which has long awaited a treatment for hyperphagia, one of the most challenging aspects of the disorder. Jennifer Miller, M.D., from the University of Florida, emphasized the impact of this drug on families dealing with PWS, who have often been forced to maintain constant supervision to restrict food access due to the relentless hunger caused by hyperphagia.

The approval of Vykat XR was supported by a phase 3 trial. This study involved a 16-week withdrawal period, during which patients who had previously received Vykat XR for a median duration of 3.3 years were observed. Those switched to placebo during this period showed a statistically significant worsening of hyperphagia compared to those who continued with the medication. Over four years of data from four open-label studies, Vykat XR demonstrated a consistent safety profile. Common adverse reactions included hypertrichosis, edema, hyperglycemia, and rash, affecting approximately 10% of patients.

Prader-Willi Syndrome affects approximately 1 in every 15,000 live births, with over 300,000 individuals impacted worldwide, according to the Prader-Willi Syndrome Association USA. Soleno Therapeutics notes that data suggests there are around 10,000 PWS patients in the United States.

Several companies have previously attempted to develop treatments for hyperphagia without success. Alize Pharma managed to achieve positive results in a phase 2 study with AZP-531, a novel unacylated ghrelin peptide analog, but could not advance the treatment further. Boston-based Zafgen demonstrated the efficacy of beloranib, a MetAP2 inhibitor, in a phase 3 trial, but safety concerns led to its discontinuation. Sweden’s Saniona developed Tesomet, a combination of tesofensine and metoprolol, which received Orphan Drug designation from the FDA in 2021. Unfortunately, its development was halted in 2022 due to funding issues. Acadia Pharmaceuticals, based in San Diego, is working on intranasal carbetocin, a treatment rejected by the FDA in 2022. Acadia obtained this candidate through a $10 million acquisition of Levo Therapeutics in Chicago.

Vykat XR's approval signifies progress in the treatment options available for PWS patients, offering new hope for families and individuals grappling with the challenges of hyperphagia.