all active subjects rolled into 209FX303/NCT01013480

Study 22001, "A Double-Blind, Placebo-Controlled, Flexible-Dose Evaluation of the Efficacy, Safety, and Tolerability of STX209 in the Treatment of Irritability in Subjects with Fragile X Syndrome" currently is evaluating the efficacy of STX209 (R-baclofen) for management of typical problem behaviors, such as irritability and aggression, in subjects with FXS. This study (22002) will enter subjects who complete Study 22001 into a long-term, open-label study.The open-label extension protocol will provide necessary data on the long-term safety and tolerability of STX209 among subjects with FXS who receive treatment under conditions more closely reflective of their general medical care.

Inclusion Criteria:

• Have completed all scheduled visits in protocol 22001 and have shown they can adequately follow the protocol, with sufficient medical justification to continue on open-label treatment with STX209, as assessed by the principal investigator

Exclusion Criteria:

• Subjects with a medical condition that might interfere with the conduct of the study, confound interpretation of the study results, or endanger their own well-being.
• The occurrence or continuation of any adverse event or condition during study 22001 that, in the opinion of the Investigator, should exclude the subject from participating in this open-label extension.