Shionogi Group company Tetra Therapeutics has received rare paediatric disease designation from the US Food and Drug Administration (FDA) for zatolmilast (BPN14770) to treat Fragile X syndrome (FXS).

FXS is a significant cause of inherited intellectual disability and autism.

This designation enables Tetra to seek a priority review voucher from the FDA, which could be utilised for a future human drug application.

In 2018, the company obtained orphan drug designation from the FDA for zatolmilast as an investigational treatment.

It is currently being assessed in a pivotal Phase IIb/III programme, which comprises two double-blind, randomised and placebo-controlled trials of 150 subjects each.

The first of these, Study 204, consists of adolescent males aged between nine and 17 and the second, Study 301, comprises adult males aged between 18 and 45.

The zatolmilast clinical programme also includes Study 302, an open-label extension study available to participants upon completion of Study 204 or 301.

The studies’ primary endpoints include a cognitive assessment of zatolmilast’s efficacy, as measured by the National Institutes of Health Toolbox Cognitive Battery’s (NIH-TCB) cognition crystallised composite score.

Secondary endpoints comprise evaluations of daily living, caregiver and clinician improvement scales and other domains from the NIH-TCB.

Tetra Therapeutics CEO Chad Coberly stated: “We are committed to advancing a potential medicine for people with Fragile X syndrome, a rare genetic disorder which affects all aspects of life for individuals and families.

“While symptoms vary among individuals, intellectual disability is one of the most prevalent neuropsychiatric hallmarks of the disorder.

Shionogi acquired Tetra in 2020 as part of its efforts to develop medications for unmet medical requirements.