STX209 (Arbaclofen) for Autism Spectrum Disorders: An 8-Week Open-Label Study
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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.
KeywordsSTX209 Arbaclofen Gamma-aminobutyric acid (GABA) Autism spectrum disorder Clinical trial
This study was funded by Seaside Therapeutics, Inc. We are grateful to the families who volunteered to participate in this study. Several of the authors are full-time employees of Seaside Therapeutics, Inc., and some hold equity in Seaside Therapeutics, Inc., the sponsor of the study. The remaining authors all served as investigators in the study, and were compensated for their study efforts by Seaside Therapeutics, Inc. Some of these authors also have served as paid consultants to Seaside Therapeutics, Inc.
Conflict of interest
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