Riluzole in Fragile X Syndrome

Riluzole in Fragile X Syndrome: A Pilot Study Incorporating Biomarker Assay

The purpose of this study is to investigate the effectiveness and tolerability of riluzole in adults with Fragile X Syndrome.

Fragile X Syndrome (FXS) represents the most common inherited form of intellectual disability. FXS is more common in males and the symptoms associated with the disorder are more marked in males. FXS is associated with characteristic physical features, behaviors, and comorbidities. Those with FXS often suffer from behavioral difficulties that include anxiety-related symptoms (shyness, social phobia, obsessive-compulsive disorder (OCD) symptoms), attention deficit hyperactivity symptoms (overarousal, hyperactivity, distractibility, impulsivity) and aggressive/self-injurious behaviors.

Riluzole is approved by the FDA for use in treating amyotrophic lateral sclerosis (ALS) in adults. Recently, riluzole has been the subject of several open-label studies describing the use of the drug in treatment-resistant depression and OCD.

Given the overlap between repetitive behavior in FXS and symptoms of OCD, it is logical to study riluzole in FXS given the compound's promise in ameliorating treatment-refractory symptoms of OCD.

Inclusion Criteria:

• Males and females age 18 years or older.
• Confirmed molecular diagnosis of Fragile X Syndrome.
• Clinical Global Impression Severity (CGI-S) score of 3 or greater.
• Significant interfering repetitive behavior as determined by the principal investigator.
• Must be in good health as determined by screening procedures including a detailed medical history, and complete physical and neurological examination.
• Dosing of concomitant medications during the study must remain stable.

Exclusion Criteria:

• Pregnancy.
• Concomitant use of another glutamatergic agent (memantine, topiramate, amantadine, among others.
• Evidence of prior trial of riluzole and/or hypersensitivity/allergic reaction to riluzole.
• Abnormal baseline liver function tests at screen or by history; or complete blood count abnormalities at screen or by history.