Safety, Tolerability and Efficacy Study of STX209 in Subjects With Fragile X Syndrome

The study objective is to explore the efficacy, safety and tolerability of STX209 for treatment of irritability in subjects with FSX. We hypothesize that STX209 will improve irritability and other typical problem behaviors associated with fragile X syndrome. We also hypothesize that STX209 will be safe and well tolerated.

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Key information

Conditions

Fragile X Syndrome Chromosome Disorders Congenital Abnormalities Congenital, Hereditary, and Neonatal Diseases and Abnormalities Genetic Diseases, Inborn Genetic Diseases, X-Linked Heredodegenerative Disorders, Nervous System Intellectual Disability Mental Disorders Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Sex Chromosome Disorders X-Linked Intellectual Disability

Age range

6 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Southwest Autism Research & Resource Center, Phoenix, Arizona, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Male or female subjects 12 to 40 years of age eventually expanding to 6 years of age
Molecular documentation of the fragile X mutation.
Clinical Global Impression - Severity (CGI-S) rating for problem behavior of moderate or higher at screening and at Visit 1
An Aberrant Behavior Checklist (ABC-C) Irritability Subscale score >12 and at least 3 items on the Irritability Subscale rated at least moderate or above.
Current treatment with no more than three psychoactive medications, including anti-epileptics.
Current pharmacological treatment regimen has been stable for at least 4 weeks.

Exclusion criteria

Subjects with a history of seizure disorder who are not currently receiving treatment with antiepileptics.
Subjects with any condition, including alcohol and drug abuse, which might interfere with the conduct of the study, confound interpretation of the study results, or endanger their own well-being. This includes, but is not limited to impairment of renal function, evidence or history of malignancy or any significant hematological, endocrine, cardiovascular, respiratory, hepatic, or gastrointestinal disease.
Subjects who plan to initiate or change pharmacologic or non-pharmacologic interventions during the course of the study.
Subjects who are currently receiving treatment with racemic baclofen.
Subjects currently treated with vigabatrin or tiagabine.
Subjects taking another investigational drug currently or within the last 30 days.

Treatment and study plan

STX209

Drug

Variable dose from 1 mg bid to 10 mg tid, Capsule, Oral, 4 weeks

Other names: arbaclofen

Placebo

Drug

variable dose (same flexible dose titration protocol), bid to tid, capsule, Oral, 4 weeks

Primary outcomes

Aberrant Behavior Checklist Irritability Subscore

Time frame: After 4 weeks of treatment

The Aberrant Behavior Checklist-Community Edition (ABC-C) is a 58-item questionnaire composed of five different independent subscales. The questionnaire is completed by the parent/caregiver and lists aberrant behaviors and asks about the severity of the problem. ABC-Irritability is one of the subscales and comprises of 15 items. Minimum score is 0, maximum is 45. A decreased score indicates few aberrant behaviors and clinical improvement. The entire ABC-C assessment is administered at baseline and then at the end of each Intervention Period (4 weeks after Baseline).

Sponsors and collaborators

Lead sponsor

Seaside Therapeutics, Inc.

Industry

Registry information

Official study title

A Double-Blind, Placebo-Controlled, Crossover, Flexible-Dose Evaluation of the Efficacy, Safety and Tolerability of STX209 in the Treatment of Irritability in Subjects With Fragile X Syndrome

Important dates

Study start: 2008
Primary completion: 2010
Study completion: 2010
First posted: Nov 10, 2008
Registry last updated: May 6, 2013

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

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