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Immediately after a severe head injury, potentially
damaging--and sometimes fatal--chemical changes occur in the
brain. The new drug, dexanabinol, inhibits this chemical
onslaught, prevents dangerous drops in blood pressure and
thwarts brain swelling. (Marco Doelling/ ABCNEWS.com)
By Jenifer Joseph
ABCNEWS.com
Oct. 8 — When Jim Wong was hit by a speeding car on a San
Francisco street five years ago, he suffered a brain injury so
severe that he lay comatose in a hospital for weeks.
After the accident, his head swelled from massive internal pressure,
cutting off blood flow to the brain and causing ongoing permanent
damage.
Doctors call this “secondary head injury,” when massive amounts of
neurochemicals surge through the brain in the hours and days after an
accident, killing large numbers of fragile brain cells. If a person doesn't die from the initial blow, they can succumb to this secondary trauma.
In Wong's case, doctors had nothing to give him to stop the
damaging flow of chemicals, so his wife and four kids could only wait
to see whether he would recover. In the years since Wong was injured, little has changed when it
comes to therapies for brain trauma patients—until now.
Marijuana Molecule
Excitement is brewing among neurosurgeons about a synthetic drug
modeled after molecules found in marijuana. Called dexanabinol, the new
compound has prompted substantial improvement in a small group of
moderate to severe head trauma patients. The drug is produced by the
biopharmaceutical company Pharmos.
The first study of the drug involved just 67 patients in Israel, half
of whom received a placebo. The treated patients received dexanabinol
injections within six hours after their accidents. After six months, 46
percent of patients who were given the drug were able to return to a
relatively normal life, compared to 32 percent of those in the placebo
group. The new drug was also associated with a lower death rate: 10
percent died in the treated group, while 13.5 percent died in the control group.
Results of the study were presented at the Congress of Neurological
Surgeons in Seattle Wednesday.
The researcher, Dr. Nachshon Knoller, noted that because it was
created as a mirror image of a marijuana molecule, dexanabinol lacks the psychotropic side effects of the original drug.
Dare Call it a Breakthrough?
Dr. David Hovda, director of Brain Injury Research at the University of
California Los Angeles, calls dexanabinol “a remarkable finding.”
One of the biggest criticisms of previous brain injury drugs, he says,
is that they looked promising in small, early studies, only to fall short
when tested on large numbers of patients. Usually, this is because they
targeted only one or two of the damaging effects that occur after brain
trauma.
But, Hovda notes, “Here we have a serendipitous discovery that
targets the most potent effects of severe head trauma. That's why I'm
excited about this.”
Dr. David Baskin, a neurosurgeon at Baylor University, echoed his
excitement, “The bottom line is that it's promising,” says Baskin, "It's not bogus stuff.”
And it may be potentially useful for other brain-damaging conditions
too. Researchers find that the drug seems to impede the cell deterioration that occurs with seizures that occur in stroke patients and in victims of nerve gas attacks.
In recent studies conducted by the U.S. Army Medical Research
Institute, brain damage was reduced by 75 percent in lab rats treated with dexanabinol five minutes after nerve gas exposure.
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