Experimental drug gives hope for rare disease, autism

4:37 AM, Sep 21, 2012   |    comments
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For the first time, a drug has shown success in treating social withdrawal symptoms in children with a rare disorder called Fragile X Syndrome, leading scientists to hope that it might also help those with autism.

The drug, called STX209, or arbaclofen, is the first to treat one of the core symptoms of Fragile X Syndrome, a leading cause of intellectual disability and the most prevalent known cause of autism.

Arbaclofen has been tested in only a small number of patients and it's not yet approved by the Food and Drug Administration.

Because about one-third of people with Fragile X have autism, researchers hope that it might also help many in the much broader autistic community, says the study's lead author, Elizabeth Berry-Kravis of Rush University Medical Center in Chicago.

"This is groundbreaking work," says Robert Ring, vice president of translational research at Autism Speaks, an advocacy group. "The arbaclofen program is perhaps the most important medicine development program running in autism today."

Robert Schultz, director of the Center on Autism Research at Children's Hospital of Philadelphia, notes,"This is the first drug in the field of autism that directly reports on improving social symptoms, and we have no other drug that does that. I'm very, very excited that this is being published."

Currently, children with Fragile X and autism undergo intensive behavioral therapy to improve their social skills. But there are no medications that help, Schultz says.

Social impairments -- along with communication problems and repetitive behaviors -- are the defining traits of autism, Ring says. Failing to socialize may exacerbate some of the other problems that often develop in people with autism, such as learning and communication deficits, as well as low IQ, Schultz says.

A drug that helps children connect with others could potentially alleviate many of these complications, by allowing them to learn more about the world around them, says Katie Clapp, co-founder of the FRAXA Research Foundation.

"Sociability opens the door to learning," says Clapp, whose 23-year-old son has Fragile X. "These kids spend so much time hovering in the corner, unable to interact with others."

In the new study, Berry-Kravis tested arbaclofen in 63 patients, ages 6 to 39, in which half were randomly assigned to get the new drug and half were given placebos. The study appears in today's Science Translational Medicine.

While patients in general advanced in their social functioning -- improving their ability to hold conversations or function in groups of people -- those with the most severe social problems got the most benefit, says Paul Wang, vice president of development at Seaside Therapeutics, which funded the trial and is developing the drug. Of 27 patients with severe "social avoidance" problems, about 40% were "much improved" or "very much improved," according to standardized tests, Wang says.

In one case, a boy was able to attend his birthday party for the first time in his life, Berry-Kravis says. In the past, he had been too shy and couldn't tolerate hearing people sing Happy Birthday to You.

Seaside Therapeutics is already enrolling Fragile X patients in a larger, definitive trial, Wang says. If that study is successful, the company will use it to apply for FDA approval of the drug for use in Fragile X.

The company also just completed an early-stage trial in autism, but the results are not yet available, Wang says.

Ari Ne'eman, president of the Autistic Self Advocacy Network, notes that a drug that works in Fragile X -- a disease with a clear genetic cause -- may not work in general autism, which researchers now describe as a collection of conditions with multiple causes but similar symptoms.

"If an intervention makes progress in helping someone navigate the world on their own terms, that's good news," Ne'eman says. "But let's remember that "looking and acting normal" aren't necessarily the only or best way to do that. ... It's important that we have a meaningful conversation about whether or not we're focusing on the outcomes that matter for making autistic people happy, instead of focusing on making us appear more non-autistic."

If successful, arbaclofen could mark the beginning of a new era in autism, both because it targets one of the condition's core problems, and because scientists know so much about how it works on a molecular level, Berry-Kravis says.

"The number of drugs potentially available for people with neurodevelopmental disorders is potentially on par with the number of drugs available for cancer," Berry-Kravis says. "But we're back where cancer researchers were in the 1960s."

There are currently no approved drugs to treat the core symptoms of autism, Schultz says. Doctors may prescribe other drugs to treat secondary symptoms, such as anxiety, but most of these medications have marginal effects, he says.

Arbaclofen is different than other drugs because it was developed by scientists studying the fundamental genetic problems in Fragile X. Arbaclofen is designed to help restore the balance of neurotransmitters, chemical messengers in the brain that communicate between cells.

"It's not a shot in the dark,"Schultz says. "It's a very rational treatment based on understanding the biology of Fragile X."

If arbaclofen succeeds, it will be a win-win for the field of autism, providing not just a new treatment, but giving scientists greater insight into the brain chemistry behind the condition, Ring says.

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