STX209 (Arbaclofen) for autism spectrum disorders: An 8-week open-label study

Craig A. Erickson, Jeremy M. Veenstra-Vanderweele, Raun D. Melmed, James T. McCracken, Lawrence D. Ginsberg, Linmarie Sikich, Lawrence Scahill, Maryann Cherubini, Peter Zarevics, Karen Walton-Bowen, Randall L. Carpenter, Mark F. Bear, Paul P. Wang, Bryan H. King

Research output: Contribution to journalArticle

66 Scopus citations


STX209 (arbaclofen), a selective GABA-B agonist, is hypothesized to modulate the balance of excitatory to inhibitory neurotransmission, and has shown preliminary evidence of benefit in fragile X syndrome. We evaluated its safety, tolerability, and efficacy in non-syndromic autism spectrum disorders, in an 8-week open-label trial enrolling 32 children and adolescents with either Autistic Disorder or Pervasive Developmental Disorder - Not Otherwise Specified, and a score ≥17 on the Aberrant Behavior Checklist (ABC) - Irritability subscale. STX209 was generally well-tolerated. The most common adverse events were agitation and irritability, which typically resolved without dose changes, and were often felt to represent spontaneous variation in underlying symptoms. Improvements were observed on several outcome measures in this exploratory trial, including the ABC-Irritability (the primary endpoint) and the Lethargy/Social Withdrawal subscales, the Social Responsiveness Scale, the CY-BOCS-PDD, and clinical global impression scales. Placebo-controlled study of STX209 is warranted.

Original languageEnglish (US)
Pages (from-to)958-964
Number of pages7
JournalJournal of Autism and Developmental Disorders
Issue number4
StatePublished - Apr 2014


  • Arbaclofen
  • Autism spectrum disorder
  • Clinical trial
  • Gamma-aminobutyric acid (GABA)
  • STX209

ASJC Scopus subject areas

  • Developmental and Educational Psychology

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  • Cite this

    Erickson, C. A., Veenstra-Vanderweele, J. M., Melmed, R. D., McCracken, J. T., Ginsberg, L. D., Sikich, L., Scahill, L., Cherubini, M., Zarevics, P., Walton-Bowen, K., Carpenter, R. L., Bear, M. F., Wang, P. P., & King, B. H. (2014). STX209 (Arbaclofen) for autism spectrum disorders: An 8-week open-label study. Journal of Autism and Developmental Disorders, 44(4), 958-964.