MEDICINAL cannabis for epilepsy has been a hot topic in Australia, particularly in Victoria where Premier Daniel Andrews made its legalisation a key pledge in his successful 2014 election campaign.
But until recently, actual evidence for the use of cannabinoids to reduce seizure frequency has been hard to come by. Now, a randomised, double-blind trial of cannabidiol, a cannabis derivative that does not contain the psychoactive ingredient tetrahydrocannabinol, has for the first time provided hard data that the treatment works.
For the study, published in the New England Journal of Medicine, a group of international researchers, including Professor Ingrid Scheffer from the University of Melbourne, randomised 120 children with the Dravet syndrome – a severe form of childhood epilepsy with often drug-resistant seizures and a high mortality rate – to either an oral cannabidiol preparation or placebo, in addition to their normal antiepileptic treatment.
Tracking the change in convulsive seizure frequency from baseline across the 14 weeks of the trial, the researchers found convulsive seizures were reduced by around 40% (from a median of 12.4 to 5.9 per month) in the treatment group, compared with 13% (from 14.9 to 14.1 per month) with placebo. The difference in convulsive seizure reduction between the two groups was both statistically significant and clinically consistent.
In 43% of patients taking cannabidiol, the number of convulsive seizures more than halved over the course of the treatment. Five percent of treated children became completely seizure-free, compared with none in the placebo arm. There was no significant reduction in non-convulsive seizures.
There was a downside, however, with 93% of the treatment group suffering from side effects, compared with 74% in the placebo arm. The most common of these were vomiting, fatigue and fever. These side effects were generally not considered serious, although eight patients in the cannabidiol group did drop out of the trial.
Professor Scheffer, who is chair of Paediatric Neurology at the University of Melbourne, described the trial findings as a “major scientific breakthrough”.
“It’s the first evidence that cannabidiol works. There have been anecdotal reports in the past, and people with firm beliefs that it works in epilepsy, but this is the first time it’s been proven,” she told MJA InSight.
Professor Scheffer cautioned that cannabidiol wasn’t a cure for these children.
“Sadly, this is not a panacea … but it does give cause to be optimistic about further research for its use. It also raises lots of questions, not just in terms of the treatment of epilepsy, but where else it could be applied medicinally.”
David Penington, an Emeritus Professor at the University of Melbourne who has long campaigned for the legalisation of medicinal cannabis, said the trial findings were “without a doubt robust”.
“It’s a very valuable study, with very credible evidence as the extent of efficacy of treatment in these severely disabled children. But it needs to be seen in context. Dravet is not the only form of juvenile epilepsy, and it remains to be seen whether this treatment has broader application in epilepsy.”
Professor Penington said that a narrow focus on medicinal cannabis for epilepsy, as has been the case in Victoria, could mean that other people who may benefit are being ignored.
“Medicinal cannabis for painful inoperable cancer or neuropathic pain, such as in multiple sclerosis, hasn’t been seen as a priority at all in Victoria. There need to be trials for pain and for people undertaking chemotherapy in addition to those for [patients with] juvenile epilepsy. I also personally believe there’s a case for people with post-traumatic stress disorder being considered for a trial.”
Professor Penington said that another problem with medicinal cannabis in Australia was that at present it’s being imported from overseas at great expense.
“I believe we can produce medicinal cannabis here at a fraction of the cost if we’re allowed to do so. Hopefully, within the next few years we’ll get approval to do that, under tightly regulated conditions.”
Australia’s approach to medical cannabis has been “very cautious and slow,” Professor Penington said, compared with other jurisdictions, in particular in many states in the US where the treatment is available for a number of conditions.
“There are many people here in Australia who are suffering and who could benefit from medicinal cannabis, and I think it’s very sad that it’s not available for them. I think we’ll come around to it step by step, but we have some distance to go.”
To find a doctor, or a job, to use GP Desktop and Doctors Health, book and track your CPD, and buy textbooks and guidelines, visit doctorportal.