FDA has granted orphan drug designation to Tris Pharma’s investigational therapy TRN-257 for the treatment of idiopathic hypersomnia, marking a regulatory milestone for the once-nightly, low-sodium oxybate candidate.

The designation was awarded on the basis that TRN-257 may be clinically superior to currently available oxybate products for idiopathic hypersomnia because its once-nightly dosing could represent a major contribution to patient care. The investigational therapy is being developed as an extended-release oral suspension designed to eliminate the need for patients to wake during the night for a second dose.

Tris said TRN-257 is also being developed with a low sodium content and is intended for the treatment of idiopathic hypersomnia as well as cataplexy or excessive daytime sleepiness associated with narcolepsy.

Under US regulations, orphan drug designation supports the development of therapies for rare diseases affecting fewer than 200,000 people in the country and may provide incentives including market exclusivity following approval.

Maurice Ohayon, professor and director of the Stanford Sleep Epidemiology Research Center at Stanford University, said: “The FDA’s orphan drug designation for TRN-257 highlights the continuing need to advance differentiated therapeutic options for this patient population. A once-nightly, low-sodium oxybate formulation may be clinically meaningful if it can reduce nocturnal treatment burden while maintaining efficacy and safety.”

Ketan Mehta, founder and chief executive officer of Tris Pharma, said: “The granting of orphan drug designation for TRN-257 recognizes the potential for a major contribution to patient care and marks an important milestone for the treatment of patients with idiopathic hypersomnia.”

He added: “TRN-257 is designed to provide clinically meaningful benefits to patients by combining once-nightly dosing with the lowest sodium content among oxybate products in development, which may be an important consideration for patients who are sensitive to or who need to manage their sodium intake.”

Idiopathic hypersomnia is a chronic neurological disorder characterised by excessive daytime sleepiness and can require lifelong treatment. Tris is also investigating TRN-257 for narcolepsy-related symptoms, including cataplexy and excessive daytime sleepiness.