Dear Families and Friends,

We would like to invite you to participate in a research study at Kennedy Krieger Institute in Baltimore, Maryland. The research study will determine if an investigational drug called arbaclofen is an effective treatment for social withdrawal symptoms associated with Fragile X syndrome. Eligible participants will be male and female, and in the age range of 5 through 11 years.

The first part of the study involves a telephone interview and a Screening Visit to determine if your child is eligible to participate in the study.  During Screening we will evaluate participants using psychological, psychiatric, medical, biological, behavioral, and developmental measures including blood draws, ECG, and urine pregnancy testing for females. The risks of this study include side effects associated with arbaclofen such as drowsiness, dizziness, weakness and fatigue (tiredness).  Some participants may also find medical procedures such as blood draws, electrocardiogram (ECG), urine testing and physical examination upsetting or uncomfortable.

Individuals who are eligible to participate may continue on to the treatment phase of the study (involving up to 5 visits and up to 12 phone calls over a 12-week period).  During the treatment phase, participants will receive the study drug, arbaclofen or a placebo (a tablet containing no active drug). Assignment to the treatment group (i.e. arbaclofen or placebo) will be decided by chance, similar to the flip of a coin. Whether your child receives placebo or study drug will be unknown to you, your child, the study team members, and the study doctor.

The goals of this study are to determine if arbaclofen improves social withdrawal symptoms in individuals with Fragile X syndrome, and what dose of arbaclofen is the most effective

For their participation, families will receive $50 compensation for each completed visit.  We also provide free parking.

Participation in this study is entirely optional. If you choose not to participate, your care at Kennedy Krieger Institute and Johns Hopkins will not be affected. More information can be found at  (Keywords: Arbaclofen + Fragile X syndrome). Please consider sharing the information with others who might be eligible to participate. If you are interested in further information without obligation, please contact the Study Coordinator at (443) 923-7619, or

Thank you for taking the time to read this. We hope to see you in the near future.


Dejan Budimirovic, M.D.
Study Clinician

Application No.: NA_00050003
Johns Hopkins Medicine
Approved May 1, 2012