From the Journals

Data supporting cannabis for childhood epilepsy remain scarce



Cannabis-based medicinal products (CBMPs) have shown early promise for refractory childhood epilepsy, but positive media attention, as well as pressure from politicians and marijuana advocacy groups, should not supplant clinical trials and acceptable standards of evidence, according to two leading experts.

In a recent invited review article, Martin Kirkpatrick, MD, of the University of Dundee (Scotland), and Finbar O’Callaghan, MD, PhD, of University College London suggested that childhood epilepsy may be easy terrain for commercial interests to break ground, and from there, build their presence.

“Children with epilepsy are at risk of being used as the ‘Trojan horse’ for the cannabis industry,” Dr. Kirkpatrick and Dr. O’Callaghan wrote in Developmental Medicine & Child Neurology.

They noted that some of the first publicized success stories involving cannabis oil for epilepsy coincided with the rise of the medicinal and recreational cannabis markets, which will constitute an estimated 55-billion-dollar industry by 2027.

“Pediatric neurologists, imbued with the need to practice evidence-based medicine and wary of prescribing unlicensed medicines that had inadequate safety data, suddenly found themselves at odds with an array of vested interests and, most unfortunately, with the families of patients who were keen to try anything that would alleviate the effects of their child’s seizures,” the investigators wrote.

According to the review, fundamental questions about cannabis remain unanswered, including concerns about safety with long-term use, and the medicinal value of various plant components, such as myrcene, a terpene that gives cannabis its characteristic smell.

“A widely discussed issue is whether the terpenes add any therapeutic benefit, contributing to the so-called entourage effect of ‘whole-plant’ medicines,” the investigators wrote. “The concept is that all the constituents of the plant together create ‘the sum of all the parts that leads to the magic or power of cannabis.’ Although commonly referred to, there is little or no robust evidence to support the entourage effect as a credible clinical concept.”

Clinical evidence for treatment of pediatric epilepsy is also lacking, according to Dr. Kirkpatrick and Dr. O’Callaghan.

“Unfortunately, apart from the studies of pure cannabidiol (CBD) in Lennox–Gastaut and Dravet syndromes and tuberous sclerosis complex, level I evidence in the field of CBMPs and refractory epilepsy is lacking,” they wrote.

While other experts have pointed out that lower-level evidence – such as patient-reported outcomes and observational data – have previously been sufficient for drug licensing, Dr. Kirkpatrick and Dr. O’Callaghan noted that such exceptions “almost always” involve conditions without any effective treatments, or drugs that are undeniably effective.

“This is not the scenario with CBMPs,” they wrote, referring to current clinical data as “low-level” evidence “suggesting … possible efficacy.”

They highlighted concerns about placebo effect with open-label epilepsy studies, citing a randomized controlled trial for Dravet syndrome, in which 27% of patients given placebo had a 50% reduction in seizure frequency.

“We need carefully designed, good-quality CBMP studies that produce results on which we can rely,” Dr. Kirkpatrick and Dr. O’Callaghan concluded. “We can then work with families to choose the best treatments for children and young people with epilepsy. We owe this to them.”


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