Hormone secretin may not help autistic children
December 8, 1999
Web posted at: 6:07 PM EST (2307 GMT)
By Sarah Yang
A single dose of secretin did not alleviate symptoms of autism and pervasive developmental disorders in children any better than a placebo, a new study found. The result, published this week in the New England Journal of Medicine, is sure to fuel the debate over the increasingly popular use of secretin for autistic children.
"The results of our study are clean and clear," said Adrian Sandler, M.D., lead author and medical director of the Olson Huff Center for Child Development in North Carolina. "There is no difference between placebo and secretin."
Fifty-six children between the ages of 4 and 10 were randomly assigned to receive a single injection of either secretin or saline solution. Two-thirds of the patients were autistic, and the rest had been diagnosed with pervasive developmental disorder. Researchers evaluated the children's performance and behavior both before the injection and at intervals up to a month afterward.
Secretin not more effective
Children from both groups showed marked improvement in some aspects, such as the ability to relate socially. But the researchers found that secretin was not significantly more effective than the placebo.
The study is the first of a dozen studies on secretin expected to be released over the next six months. The National Institute of Child Health and Human Development helped fund some of the trials because secretin had become so widely used in autism treatment, said Marie Bristol-Power, Ph.D., special assistant for the institute's autism program.
The Food and Drug Administration approved the use of secretin -- a hormone produced in the intestines to help digestion -- as a diagnostic tool in gastrointestinal disorders. But once a drug is approved, physicians can prescribe secretin "off-label" for other uses. The biological version of the drug is derived from pig intestines, while the synthetic form -- the type used in this study -- is based upon pure human secretin.
"We really don't know what the implications are for multiple usage," said Bristol-Power, who notes that the drug was originally intended to be used in single doses. Still, she said, many relatives of the estimated 400,000 Americans who suffer from autism are desperate for answers.
Symptoms of autism
Autism strikes parts of the brain responsible for attention, memory and emotions. Symptoms may include a withdrawal from social interaction, problems learning language and repetitive movements such as rocking or spinning. What causes autism is still a mystery, but links have been suggested to such factors as chromosomal defects, viruses and environmental toxins.
No one knows exactly why a digestion hormone would affect the symptoms of autism, but many health experts estimate at least half of those with autism also suffer from significant gastrointestinal problems, including chronic diarrhea, constipation and abdominal pain.
Bristol-Power said this first study will probably not quell the enthusiasm for secretin for many people. Indeed, investigators note that 69 percent of the parents who participated in the study still wanted to pursue secretin as a form of treatment for their children despite the findings.
Fred Volkmar, M.D., professor of child psychiatry at the Yale University School of Medicine, attributes the parents' attitude to the media. Interest in secretin soared after the press picked up the story of a 3-year-old autistic boy who showed dramatic improvements a week to 10 days after one hormone injection.
"Because of the tremendous media hype, people see a vast cure in the absence of knowing about the safety of this product," said Volkmar, who wrote an editorial accompanying the study. He added that the pursuit of unproven treatments may drain resources away from existing therapies.
Secretin still has backers
Proponents of secretin -- including parents of autistic children and many health experts who are dissatisfied with available treatments -- bristle at such arguments. The medical establishment has been "quite powerless in addressing the medical needs of our children," said Ricci Hedequist, a Seattle mother of a 7-year-old autistic boy and moderator of two Internet list groups dedicated to the disorder. "We've been handed crumbs for too long."
She credits secretin for her son's improved ability to make eye contact and engage with his surroundings. "Secretin is addressing a symptom that seems to profoundly affect a significant subgroup of children with the autism label," she said. "The detractors are those people who can't see past the label."
Bernard Rimland, Ph.D., director of the Autism Research Institute in San Diego and one of the staunchest defenders of secretin's use in autism, characterizes the research as just the "top half of the first inning of this game."
Rimland -- who owns shares in RepliGen Corporation, the Massachusetts biopharmaceutical company that owns the patent for secretin's use in treating autism -- questions the adequacy of the evaluation measures used in the study. "They are intended to diagnose autism, and are not sensitive to changes brought on by short-term treatment," he said.
The study's authors acknowledge weaknesses in the study, including its short duration, the use of one rather than many doses and the use of the synthetic instead of the biological hormone.
But regarding this last point, Sandler said the two versions of secretin should be pharmacologically equivalent. "It makes no sense to me that the (pig intestine) product is somehow biologically active in humans in a way that the human product is not," he said.
Bristol-Power says that until more studies provide more answers, patients should be cautious. "As is always the case, medical decisions should be made between the parent and the physician involved."
Copyright 1999 WebMD, Inc. All rights reserved.
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Vaccines and autism
National Institute of Child Health and Human Development
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