Study Raises Hopes for Adhd Medical Test, more about PET Scans
New York Times Syndicate, Naomi Aoki, March 14, 2001
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Boston Life Sciences Inc. Monday said results from a second study have
confirmed earlier findings that identified a clear-cut chemical abnormality
the brains of people with attention deficit-hyperactivity disorder, raising
hopes for a long-sought medical test to diagnose the disease.
Such a test would go far to resolve an intense controversy about whether
medications such as Ritalin are being overprescribed as a treatment for
a condition estimated to affect as much as 7 percent of U.S. schoolchildren
and 5 percent of adults.
The study of the Boston company's diagnostic agent, dubbed Altropane, is the
second of three test phases generally required by the U.S. Food and Drug
Administration before a company can seek approval to market a product.
said the company plans to start the final phase of testing in three or four
If proven effective, it could become the first medical test to diagnose the
psychiatric disorder. While other tests such as PET scans and MRIs have
detected slight differences in the brain function of ADHD patients, none
been specific enough to hold promise as a diagnostic test.
"This is the first time that we've had the promise of an objective lab
measure for ADHD," said Russell Barkley, who researches the condition at
University of Massachusetts Medical Center and was involved in the study.
still have a lot of work to do, but we've never been this close before."
Currently, ADHD is diagnosed based on a patient's history and psychological
testing, lending an element of ambiguity to the diagnosis. People with the
disorder tend to be overly active, distractible, unfocused and impulsive,
making everyday activities such as work, school and social gatherings
But over the years, the condition has come under increasing scrutiny, with
critics alleging the disease is overdiagnosed and drugs like Ritalin
overprescribed. The most ardent of critics have even dismissed the disease
a figment of psychiatric imaginations.
"Parents are concerned about it, and professionals are concerned about
said Dr. Marc Lanser, founder and chief scientific officer of Boston Life
Sciences. "Society has a right to be concerned about unnecessarily treating
adults and children with behavior-modifying drugs."
The recently completed study confirmed earlier research that patients with
ADHD have a chemical abnormality in a part of the brain that uses the nerve
messenger dopamine, providing scientific evidence of the disease and a
possible way to diagnose it. Dopamine helps regulate attention and inhibits
Twenty adults in the study who had been diagnosed with ADHD using standard
tests had much more of a protein called the dopamine transporter than did
20 people in the study without the condition, Lanser said.
Altropane is a radioactively tagged chemical agent that attaches itself to
dopamine transporters, making them readily apparent on brain scans. The
diagnostic agent was developed to help diagnose Parkinson's disease. Boston
Life Sciences, a tiny biotechnology company located on Boston's Newbury
Street, plans to file for regulatory approval for that use later this year.
But researchers at Massachusetts General Hospital came up with the idea of
studying it as a possible diagnostic tool for ADHD since drugs such as
had been shown to work by blocking dopamine transporters. The findings of
initial study, published in December 1999, were promising but needed to be
repeated in a separate study to gain scientific merit.
The company's study is exciting because it did that, said Dr. Alan J.
Fischman, an MGH nuclear medicine specialist and senior author of the
study. But there are still many scientific and regulatory hurdles to
Fischman said. And even if all goes well, an approved test is at least a
couple years away.
The company needs to test Altropane in a large-scale study before it can be
sure of the diagnostic agent's usefulness in diagnosing the disorder. And
importantly, Fischman said, it needs to test the agent in children, the
at the center of the most heated controversies surrounding ADHD.
The company has plans to begin testing Altropane in adolescents with ADHD
later in younger children, Lanser said. Although Lanser said Altropane is
at the current level of radioactivity, the company is researching ways to
lower the dosage without compromising the effectiveness of the test.
Despite the cautions, Fischman and Barkley said, they are optimistic about
prospects for developing a diagnostic test based on Altropane. Genetic
research has also uncovered a possible link between the dopamine transporter
gene and patients with ADHD, Barkley said.
"So you see the pieces of the puzzle are all beginning to fit together,
is why I think this is absolutely fascinating," Barkley said.
One day, the diagnostic agent might even become the basis of a better drug
treat the disease. Lanser said a drug similar to Altropane will enter human
clinical trials this year to test it as a possible treatment for Parkinson's
disease. If it proves safe, the company will also pursue it as a treatment
"I think this news is very important, for us obviously, but also for the
world at large," Lanser said.
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