Seaside Therapeutics commences STX209 Phase 3 study in fragile X syndrome

Seaside Therapeutics, Inc. announced today the initiation of a randomized, double-blind, placebo-controlled Phase 3 study to evaluate the effects of STX209 (arbaclofen) on social impairment in adolescents and adults (ages 12 to 25) with fragile X syndrome. A second study in children (ages 5 to 11) is expected to begin in early summer. STX209 is an oral selective gamma-amino butyric acid type B (GABA-B) receptor agonist.

"STX209 may be able to play a much needed role in improving the core symptoms of fragile X syndrome and in helping patients and their families achieve an improved quality of life," said Randall L. Carpenter, M.D., President and Chief Executive Officer of Seaside Therapeutics. "In our Phase 2 study, we were very excited to observe clinically meaningful improvements in social impairment in patients receiving STX209—marking the first time a drug candidate has positively impacted a core symptom of fragile X syndrome. The Phase 3 study is the most comprehensive study ever undertaken in patients with fragile X syndrome and represents the first time that a drug candidate will be evaluated for a core symptom of fragile X syndrome as the primary endpoint."