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One night in 2006, Kathy Roberts rushed her autistic daughter, 

Jenny, to the hospital. Nothing had been able to stop the young woman, then in her mid-20s,

from vomiting. Jenny had recently suffered several major seizures and her entire

gastrointestinal system was going haywire.

To try to calm Jenny's GI tract, doctors at Massachusetts General Hospital prescribed baclofen,

an antispasmodic drug that is also being studied as a potential treatment for alcoholism and

other addictions. The drug relieved Jenny's vomiting, but it did something else too — a

completely unexpected and welcome side effect. (More on TIME.com: Could Anorexia Be

a 'Female' Form of Autism?)

"Within 24 hours, I saw a change," says Roberts. "Right away, I saw that it was globally

calming. I've always described a state that she would get into where it seemed like she wasn't

comfortable in her own skin, and was trying to crawl out. I saw that calmed down."

Roberts, founder of the Giant Step school for children with autism in Southport, Conn., called

Mark Bear, professor of neuroscience at MIT and advisory board member of Giant Step. In

2005, Bear had co-founded a drug company called Seaside Therapeutics to develop treatments 

for autism and other developmental disorders. Roberts told Bear about baclofen's effect on her

daughter, and a new line of research was born. (More on TIME.com: Picky Eating May Be

Early Sign of Autism)

In September, Seaside announced positive results from a phase II clinical trial of STX209, an

experimental drug that is chemically related to baclofen. In the trial, which was not blinded or

placebo controlled, STX209 led to a reduction in agitation and related emotional outbursts in

autistic people. Such behavior is common in people with autism — often, a result of anxiety

caused by extreme sensory oversensitivity or frustration over being unable to communicate

their needs. To cope, autistic people often develop behavioral mechanisms, include tantrums,

social withdrawal or repetitive behaviors like rocking or hand flapping.

STX209, while not a cure, appeared to ease anxiety. "We're seeing reductions in a lot of types

of outbursts and irritable behavior, along with increased communication and social behavior,"

says Dr. Randall Carpenter, co-founder, president and CEO of Seaside. ...

 

Carpenter says that participants in both of Seaside's STX209 trials were offered the option to

switch to baclofen once the trial was complete, if they thought their children had been helped.

"After about eight or 10 people tried it, the parents and clinicians were up in arms because they

didn't think [baclofen] was working as well as what they'd seen in trial," he says. "The FDA

allowed us to continue [treating people with STX209] under its provisions for compassionate

use. Some are coming up on a year now and they continue to see improvement and stay on.

Very few have dropped out."

Whether the drug will prove safe and effective in the long term, of course, is yet to be seen.

But with no drugs approved for Fragile X and only two to treat autism — both aimed at

relieving symptoms rather than treating the underlying problem — the development of

STX209 will undoubtedly be closely watched, both by parents and the pharmaceutical

industry.