Seaside Therapeutics is working to deliver drug treatments that address the underlying causes of developmental disorders like Fragile X syndrome. Right now, Seaside is testing an investigational medicine for people with Fragile X syndrome to improve social function.

Social impairment seen in people with Fragile X syndrome can appear in many different ways. If your family member shows any of the following behaviors, or any others that limit their ability to form social connections, he or she may be eligible to participate in the Harbor Trials:

  • Is not able to read social cues
  • Has difficulty with social behavior
  • Is unable to understand social nuances

  • Is difficult to reach or contact
  • Has a negative response to affection
  • Is socially awkward


The Harbor Trials are designed to test the safety and effectiveness of the investigational drug STX209 (arbaclofen) versus placebo (inactive pills) in improving social function in people with Fragile X syndrome. Harbor-C will study children (ages 5-11). Harbor-A will enroll adolescents and adults (ages 12-50). Eligible participants will receive up to 2 months of treatment with the study drug (STX209 or placebo) and can continue on STX209 in a long-term follow up study. Travel cost reimbursement is available.

These studies are sponsored by Seaside Therapeutics. 25 sites in the U.S. are currently enrolling. Additional information may be found on www.harbortrial.com or www.clinicaltrials.gov (references # NCT01282268 and NCT01325220).

Click the button above to be contacted by one of the research sites about these trials.