The Children’s Hospital of Philadelphia will be a site for a Phase III clinical trial to test the efficacy of a cannabis extract for treating severe childhood epilepsy. The marijuana-based treatment, or cannabidiol (CBD), has already shown signs of success. It garnered wide attention following the August 2013 airing of “Weed,” a CNN news report in which Dr. Sanjay Gupta featured an 8-year-old Colorado girl whose epilepsy symptoms have been alleviated with the use of CBD.
“Patients started asking me about it,” says CHOP pediatric neurologist Eric Marsh, MD, PhD. After learning of a Stanford colleague’s report citing positive results and of the availability of a high-CBD compound from GW Pharmaceuticals, Marsh decided to run an expanded access protocol for his patients. Because marijuana is classified by the U.S. government as a Schedule 1 drug, defined by the Drug Enforcement Administration (DEA) as one with “no currently accepted medical use and a high potential for abuse,” Marsh was required to obtain a Schedule 1 license from the DEA. This entailed interviews and inspections by DEA agents, a long process that Marsh calls “well worth it, particularly for those patients who have run out of options.”
Several theories exist about how CBD, or Epidiolex, works on epilepsy. “There are multiple mechanisms of action,” says Marsh, citing the blockage of both sodium channels and serotonin receptors, as well as the reduction of calcium. “CBD is also a possible potent anti-inflammatory agent,” he adds.
The 25 CHOP patients who tested the CBD, which was administered orally in the form of an oil, range in age from 3 to 19. All have severe epilepsy, including many with Dravet and Lennox-Gastaux syndromes. Although their conditions vary, they all experience seizures, from as few as eight per month to as many as 300. All are cognitively delayed or impaired; many cannot walk or talk. During the protocol, the patients were monitored closely, says Marsh, to ensure safety and to watch for adverse interactions with other medications. “There seemed to be some positive results,” he says. “We saw some dramatic reductions in the incidence of seizures. For example, patients who might have been having 40 to 50 seizures per month stopped having them at all.” Many patients also showed improvement in walking and talking. For others, however, the CBD had little or no effect. Some reacted negatively, such as becoming more sedate.
“As with any new anti-epileptic treatment, there are both positive and negative effects,” says Marsh, “but there appear to be real positives.” That’s why he believes it’s critical to get the results of a Phase III placebo-controlled study, like the one his patients will join — and soon. “It’s really important to get definitive answers on CBD,” he says. “If we see a lot of promising results, it needs to be out there.”