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Early Results from Autism Study: Arbaclofen May Improve Sociability

If benefits and safety confirmed by additional trials, medicine could become first to treat a core symptom of autism
May 01, 2013


Today, researchers reported the promising results from a clinical trial testing an experimental medicine for increasing sociability in children and young adults with autism. If larger studies confirm its benefits and safety, the compound – arbaclofen – could become the first medicine to treat one of autism’s core symptoms.

“These initial results are exciting and suggest that arbaclofen may help some children with autism,” said Vanderbilt University child psychiatrist Jeremy Veenstra- VanderWeele, M.D. “We hope that future studies will clarify who is most likely to benefit and what symptoms are most likely to improve.”

Dr. Veenstra-VanderWeele presented the preliminary findings today at the International Meeting for Autism Research, in San Sebastian, Spain. Co-investigators included scientists from Seaside Therapeutics in Massachusetts. The biotech company holds the rights to develop arbaclofen, also known as compound STX209.

The 12-week study enrolled 150 participants, ages 5 to 21, at two dozen sites across the United States. Half received arbaclofen. The other half received a dummy pill, or placebo. The study was “blinded,” meaning no one knew who received the real treatment until after the results were tallied.

Throughout the study, parents filled out questionnaires and physician’s conducted assessments to measure changes in behavior. The parent-rated measures showed similar improvements in both groups (arbaclofen or placebo). By contrast, the physician assessments showed significantly greater improvements in overall symptoms among those who received arbaclofen. The researchers also saw evidence that participants with relatively higher IQs may have benefitted the most from the treatment. 

The study also tracked side effects. Ten participants – eight on arbaclofen and two on placebo – withdrew from the study because of adverse effects. These related mostly to problem behaviors such as aggression or sleep disturbance. The medicine’s most common side effect was drowsiness. 

“If these promising results can be replicated, arbaclofen may be the first drug that can improve sociability in individuals with autism,” commented Autism Speaks Chief Science Officer Geri Dawson, Ph.D. “This would be a historical leap forward and open the door for more research on drugs that address core symptoms.”

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