RARE Daily

FDA Grants Rare Pediatric Disease Designation to Tonix TNX-2900 for Prader-Willi Syndrome

March 25, 2024

Rare Daily Staff

The U.S. Food and Drug Administration has granted Rare Pediatric Disease Designation to Tonix Pharmaceuticals’ TNX-2900 to treat Prader-Willi syndrome in children and adolescents.

TNX-2900 is a proprietary magnesium-potentiated formulation of intranasal oxytocin, a naturally occurring hormone that reduces appetite and eating.

Prader-Willi syndrome (PWS) is the most common genetic cause of life-threatening childhood obesity and affects males and females with equal frequency. PWS results from the absence of expression of a group of genes on the paternally acquired chromosome 15. The hallmarks of PWS are lack of suckling in newborns and, in children and adolescents, severe hyperphagia – an overriding physiological drive to eat, leading to severe obesity and other complications associated with significant mortality. A systematic review of the morbidity and mortality as a consequence of hyperphagia in PWS found that the average age of death in PWS was 22.1 years. There is no approved medication to treat poor feeding in newborns or hyperphagia in children and adolescents with PWS.

Oxytocin has potent effects in correcting behavioral characteristics of the Magel2 knock-out mouse model for PWS and autism. Six clinical trials have investigated intranasal oxytocin as a treatment in pediatric patients with PWS. Four studies showed evidence for improvement in PWS-related behaviors/symptoms; three clinical studies reported evidence for improvement in hyperphagia; and one clinical study showed an improvement in sucking in infants.

TNX-2900 is based on Tonix’s patented intranasal Mg2+-potentiated oxytocin formulation intended for use by children and adolescents. This formulation is believed to enhance the potency of oxytocin as well as increase specificity for oxytocin receptors relative to vasopressin receptors, potentially reducing unwanted side effects from activating vasopressin receptors.

“The Rare Pediatric Disease designation is an important regulatory milestone in the development of TNX-2900,” said Seth Lederman, CEO of Tonix Pharmaceuticals. “As PWS is a genetic disorder associated with abnormalities of the oxytocin system, Tonix believes TNX-2900’s unique formulation has the potential to improve intranasal oxytocin’s therapeutic action by addressing limitations in efficacy observed at high-dose intranasal oxytocin that is not Mg2+-potentiated.”

The FDA grants Rare Pediatric Disease designation to incentivize development of new treatments for serious or life-threatening diseases that primarily affect children ages 18 years or younger with fewer than 200,000 people affected in the United States. The RPDD program allows for a sponsor who receives an approval to qualify for a priority review voucher that can be deemed to receive an expedited six-month priority review for any subsequent marketing application or may be sold or transferred.

If TNX-2900 is approved for marketing, Tonix may qualify for a priority review voucher that can be redeemed to receive priority review of a subsequent marketing application for a different product. Priority review vouchers may also be sold or transferred to another sponsor. The vouchers have been an important source of non-dilutive funding to rare disease drug developers who have typically been able to sell these vouchers for around $100 million, although prices have ranged from $65 million to $350 million.

Photo: Seth Lederman, CEO of Tonix Pharmaceuticals

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