Could Marijuana Chemical Help Ease Epilepsy? Early research suggests yes, but laws limit access to the drug and its compounds

https://www.nlm.nih.gov/medlineplus/news/fullstory_154535.html
Wednesday, September 9, 2015
WEDNESDAY, Sept. 9, 2015 (HealthDay News) -- A
chemical found in marijuana might help prevent epilepsy seizures, but
drug laws have hampered research efforts, a new study says.

Cannabidiol is one of the main active chemical compounds found in
pot. But it doesn't make people high, the study authors said.
Cannabidiol has already been shown to prevent seizures in animal studies
and in one ongoing human trial, said lead author Dr. Daniel Friedman, a
neurologist and epilepsy specialist at NYU Langone Medical Center in
New York City.


But legally, marijuana is considered a Schedule I controlled
substance. That means the U.S. Drug Enforcement Agency classifies it as a
drug with "no currently accepted medical use and a high potential for
abuse." That classification makes it difficult to pursue large-scale
trials that could prove cannabidiol's safety and effectiveness in
epilepsy, Friedman said.


"Right now, the evidence for the utility of cannabinoids, and
particularly cannabidiol, for the treatment of severe epilepsy is
intriguing, but the definitive proof is not there yet," Friedman said.


Epilepsy Foundation President and CEO Phil Gattone said the review
highlights how current federal laws have limited our understanding of
marijuana's potential effectiveness as an anti-seizure medication.


"Friedman and [co-author Dr. Orrin] Devinsky point out that while we
don't know all of the long-term and short-term side effects of using
cannabis and cannabidiol, we do know the impact of uncontrolled
epilepsy, and that must be considered when looking at the use of
cannabis," Gattone said.


About 30 percent of people with epilepsy continue to have
uncontrolled seizures, even though there are more than 20 different
anti-seizure drugs currently on the market, the authors said.


The study is published in the Sept. 10 issue of the New England Journal of Medicine.


In their review of the current evidence, the researchers explained a
major brain receptor that responds to marijuana -- cannabinoid receptor
1, or CB1 -- appears to have anti-seizure effects when activated.


CB1 receptors are most strongly activated by THC, the chemical in pot
that causes intoxication. But a review of animal studies found that
non-intoxicating cannabidiol shows the most promise in preventing
seizures, the researchers said.


"When you look at the combined weight of the animal data, it appears
that cannabidiol appears to have the most consistent anti-seizure
effect," Friedman said, adding that the anti-seizure effects of
cannabidiol are not fully understood.


One ongoing human trial involving Epidiolex, a British-made cannabis
extract that's 99 percent cannabidiol, has shown that the chemical can
be effective in humans, he said.


In the trial, several institutions in the United States received
compassionate use waivers from the U.S. Food and Drug Administration to
give the medication to people with severe childhood-onset epilepsy who
haven't responded to available medical therapy, Friedman said.


About two out of every five patients with severe treatment-resistant
epilepsy experienced a 50 percent reduction in the frequency of their
major seizures, he said.


"A handful of these children and young adults with epilepsy who have
never had prolonged periods of seizure freedom did actually become
seizure-free, at least in the short-term of this study," Friedman said.


Based on these results, at least three companies are developing
cannabidiol-based drugs, and trials are either underway or set to start
soon, he said.


But the results may be marred by the fact that this was an open-label
trial, in which both the researchers and the patients knew what drug
was being administered, Friedman added. As a result, people may have
experienced some improvement just because they expected the drug to
produce positive results.


There are also some concerns regarding marijuana's effect on the
developing brain. Studies involving recreational users have shown that
pot can alter the structure of the brain in young people, the authors
said.


On the other hand, severe epilepsy itself can affect brain
development, and researchers suspect some of the approved anti-seizure
medications may also affect the brain, Friedman said.


"Until we get more long-term safety data, there will have to be a
risk-benefit calculation made by the physician and the parents," he
said.


In testimony before Congress this June, the director of the U.S.
National Institute on Drug Abuse said that her agency will support
future cannabidiol (CBD) research.


"There is significant preliminary research supporting the potential
therapeutic value of CBD, and while it is not yet sufficient to support
drug approval, it highlights the need for rigorous clinical research in
this area. There are barriers that should be addressed to facilitate
more research in this area," Dr. Nora Volkow said before the U.S. Senate
Drug Caucus.


Dr. Nathan Fountain, chair of the Epilepsy Foundation Professional
Advisory Board, said he hopes the upcoming clinical trials will resolve
these questions.


"Cannabidiol has promise as a new treatment but has not yet been
subjected to rigorous clinical trials to determine the risks and
benefits of its use," said Fountain, who's also a professor of neurology
at the University of Virginia School of Medicine. "I am anxious to know
if it will be useful, as is the whole epilepsy community, although I'm
not aware of any study or observation that it will be better than other
treatments in development."





SOURCES: Daniel Friedman, M.D., neurologist and epilepsy
specialist, NYU Langone Medical Center, New York City; Phil Gattone,
president and CEO, Epilepsy Foundation; Nathan Fountain, M.D., chair,
Epilepsy Foundation Professional Advisory Board, and professor of
neurology, University of Virginia School of Medicine, Charlottesville,
Va.; Sept. 10, 2015, New England Journal of Medicine



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