Phase 2 trial of nasal spray for Prader-Willi hunger delayed to 2027
Tonix says trial of oxytocin spray TNX-2900 will start early next year
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Tonix Pharmaceuticals has pushed back the planned start of a Phase 2 clinical trial testing its oxytocin-containing TNX-2900 nasal spray in children and adolescents with Prader-Willi syndrome (PWS).
Tonix had expected the U.S.-based study, which has been cleared by the U.S. Food and Drug Administration (FDA), to start this year. It will now begin sometime in the first three months of 2027, as announced in a company press release announcing first-quarter financial results and operational updates.
PWS is caused by the loss of function of certain genes on chromosome 15. A hallmark Prader-Willi symptom is hyperphagia, an excessive hunger that isn’t relieved by eating and can lead to obesity and risky food-seeking behaviors.
Current strategies — such as diet, exercise, and restricting food access — are difficult to maintain and can lead to other behavioral challenges.
Oxytocin is involved in regulating emotional behaviors and feelings such as empathy, trust, and satisfaction from food. In people with PWS, the brain’s production of oxytocin is impaired, and this is thought to contribute to hyperphagia.
Oxytocin as potential strategy
Increasing oxytocin levels in the brain has emerged as a potential strategy for helping reduce hyperphagia and normalize eating behaviors in PWS patients. However, oxytocin-based therapies tested in clinical trials for PWS have so far shown inconsistent efficacy.
Acadia Pharmaceuticals discontinued the development of ACP-101, its experimental nasal spray of a lab-made version of oxytocin, after the therapy failed to meet the goals of a global Phase 3 clinical trial (NCT06173531).
TNX-2900 contains a potentiated form of oxytocin that Tonix believes has greater specificity for oxytocin receptor proteins than naturally occurring oxytocin and other lab-made versions. This stronger, more targeted oxytocin receptor binding is expected to boost TNX-2900’s potential therapeutic effect in PWS.
The FDA has granted TNX-2900 both orphan drug and rare pediatric disease designations for PWS. These designations are designed to encourage the development of therapies for rare diseases by providing financial benefits, market exclusivity, or other regulatory perks.
The planned Phase 2 trial of TNX-2900 will recruit PWS patients ages 8 to 17.5. Participants will be randomly assigned to receive one of three TNX-2900 doses or a placebo for 12 weeks (three months).
The study’s main goal will be to assess changes in hyperphagia. Secondary goals include TNX-2900’s safety and its effects on behavior, caregiver burden, and quality of life.
