Compound in cannabis may help treat epilepsy, researchers say
British researchers have determined that a little-studied chemical in the cannabis plant could lead to effective treatments for epilepsy, with few to no side effects.
The team at Britain’s University of Reading, working with GW Pharmaceuticals and Otsuka Pharmaceuticals, tested cannabidivarin, or CBDV, in rats and mice afflicted with six types of epilepsy and found it “strongly suppressed seizures” without causing the uncontrollable shaking and other side effects of existing anti-epilepsy drugs.
According to the findings, reported this week in the British Journal of Pharmacology, CBDV also delayed and reduced seizures when used in conjunction with two common anti-convulsant drugs.
“There is a pressing need for better treatments for epilepsy,” said Dr. Ben Whalley, the lead researcher. “It’s a chronic condition with no cure and currently, in around one third of cases, the currently available treatments do not work, cause serious side-effects and increase fatalities.”
The study, he added, highlights “the potential for a solution based on cannabinoid science. It has shown that cannabidivarin is the most effective and best tolerated anticonvulsant plant cannabinoid investigated to date.”
The casual use of marijuana -- or cannabis -- to control seizures dates back to ancient times. Its most prominent component, THC, is among those shown in animal studies to have strong anti-convulsant properties, but its mind-altering effects have made it unsuitable for pharmaceutical development.
A number of the plant’s more than 100 cannabinoids are non-psychoactive, however. The most studied among them is cannabidiol, or CBD, which has shown promise for multiple sclerosis spacticity, nausea, epilepsy and schizophrenia. Animal studies with CBD have also shown it to be effective as a neuoroprotectant and cancer-fighting agent.
In recent years, California’s medical marijuana proponents have begun to breed plants for higher CBD content and develop customized tinctures for patients with a range of ailments. Those treatments combine high doses of CBD with smaller amounts of THC.
Yet CBD’s widely known structure and well-studied uses mean that the pharmaceutical industry has less of an opportunity to protect patents on its use and profit from any drug development, said Whalley and Raphael Mechoulam, the Israeli researcher who first identified the structure of the compound nearly half a century ago and has conducted many key CBD studies.
CBDV is a closely related chemical compound. While it was discovered in 1969, the research made public this week was the first conducted in animals, said Whalley, and only two small in vitro studies have been published, neither of them related to epilepsy.
“The commercial protection can be good even if the compound itself was identified some time ago, as long as the proposed use is novel,” he said. “The better described the ‘new use’ is, the stronger the protection.”
Medical marijuana proponents largely dismiss pharmaceutical industry efforts as too profit-driven, and say that encourages researchers to find a “magic bullet” compound rather than work with the complex benefits that the whole plant provides. Yet Whalley countered that “to make a cannabis-based medicine available and accessible to a global patient community, the only viable route is via conventional drug development, which is dictated by governmental legislation [and] regulation.”
Dr. Stephen Wright, research and development director for GW Pharmaceuticals, which already markets a drug outside the U.S. that is half THC and half CBD for multiple sclerosis patients, said the company hoped to advance the CBDV research on epilepsy to human trials by next year.
Epilepsy affects about 1% of people worldwide, and is caused by excessive electrical activity in the brain, which leads to seizures that can be fatal.
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