Akron Children’s joins clinical study for fragile X syndrome


Akron Children’s Hospital has joined a phase three study of a potential new drug for the treatment of social impairment in adolescents and adults (ages 12 to 25) with fragile X syndrome. Patients are now being enrolled.

Carol Delahunty, MD, a developmental-behavioral pediatrician at Akron Children’s, is overseeing the randomized, double-blind, placebo-controlled clinical trial for the drug STX209.

Akron Children’s is also enrolling children ages 5 to 11 with fragile X syndrome in a second study of STX209.

Fragile X syndrome is a neurodevelopmental disorder characterized by impaired social function, cognition and speech, as well as attention deficits and low functional independence.

It is the most common inherited form of intellectual disability and affects approximately 1 in 3,600 males and 1 in 4,000 to 6,000 females. It is the most common known cause of autism.

The drug being studied, STX209, is an oral selective gamma-amino butyric acid type B (GABA-B) receptor agonist developed by Seaside Therapeutics, Inc., of Cambridge, Mass., the trial sponsor.

The studies follow recently-released results from a phase two study of STX209, which showed clinically meaningful improvements on global and specific neurobehavioral outcomes in the general study population. The improvements were statistically significant in the subset of pediatric patients with more severe impairments in sociability, a core symptom of fragile X syndrome.

“There are currently no FDA-approved treatments for patients with fragile X syndrome,” said Dr. Delahunty. “STX209 has the potential to play a much needed role in improving the core symptoms of fragile X syndrome and helping patients and families achieve an improved quality of life.”

The study is designed to measure the efficacy, safety and tolerability of STX209. The primary goal is to evaluate social withdrawal. Patients will be randomized to receive STX209 or a placebo and treated over eight weeks. Active treatment will be followed by a withdrawal period and a follow-up period.

Fragile X syndrome is caused by a mutation of a single gene, the fragile X mental retardation 1 (FMR1) gene on the X chromosome. The FMR1 gene produces a protein needed for normal brain development. Individuals with fragile X lack this protein and, as a result, the majority of affected individuals will have significant intellectual disabilities, requiring lifelong care.

“This study represents a paradigm shift in the way the medical community is looking at treatments for neurodevelopmental disorders like fragile X syndrome,” said Dr. Delahunty.

Akron Children’s is one of approximately 20 clinical sites in the United States. For more information about the study, contact 330-543-5012. 

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News Facts
  • Fragile X is the most common cause of autism.
  • Akron Children's is one of about 20 clinical sites in the United States participating in the phase 3 study of drug STX209. 
  • Akron Children's established the first Fragile X program in Ohio.
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Clinical study of drug has potential to improve core symptoms of fragile X syndrome

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