The GW Pharmaceuticals product has shown confirmed efficacy in LGS, though the study failed to produce a firm conclusion regarding its efficacy in other drug-resistant epilepsies.
Results from a retrospective review of electronic medical records of patients with drug-resistant epilepsy treated at the comprehensive epilepsy program at the University of California, Irvine Medical Center, offer confirmation of the effectiveness of cannabidiol (CBD; Epidiolex; GW Pharmaceuticals) in this patient population.1
In all 3 patient groups assessed (n = 33), which included those with focal epilepsy (n = 12), Lennox-Gastaut syndrome (LGS; n = 19), and primary generalized epilepsy (n = 2), there was a 58.2% mean reduction in seizure frequency (P = 0.002). The data were presented virtually at the 2020 American Epilepsy Society (AES) Annual Meeting, December 4–8, 2020, by Batool Hussain, MBBS, neurology resident physician, University of California, Irvine.
“Since limited data exists with regards to cannabidiol’s efficacy in treating epilepsies other than LGS or Dravet [syndrome], and up to 35% of patients with drug-resistant epilepsy have inadequate seizure control despite currently available treatments, the objective of our study was to determine whether CBD would be effective in reducing seizure frequency in epileptic conditions other than LGS and Dravet,” Hussain et al. wrote.
“The idea behind this project was the fact that there’s been a spark in the interest regarding CBD and CBD-derived products in the last decade or so, and there have been about 7 expanded open-label trials that have studied the use of Epidiolex in patients with treatment-resistant epilepsies, and have shown mean reduction in seizure frequency,” Hussain said.
The study included33 of 57 patients who had been prescribed the therapy at the UC Irvine center, of which 33 between ages of 20 and 60 years received the therapy for an average time of 9 months (range, 3–17) were included.
Those with LGS reported a mean reduction of 52.6% in seizure frequency (P = .002), while those focal epilepsy had a mean percentage reduction of 61.7% in seizure frequency (P = .139).
In total, 21.2% of the patients discontinued the treatment due to adverse effects (AEs) or lack of efficacy. The most common AEs reported were gastrointestinal problems, including diarrhea, nausea, vomiting, and elevated liver enzymes, as well as increased levels of sedation among those using it in combination with clobazam. Medication interactions were noted most commonly with clobazam (n = 7), as well as valproic acid (n = 3), zonisamide (n = 2), and lamotrigine (n = 1).
Although the results for those with epilepsies other than LGS were not statistically significant, Hussain noted that this was in part because the sample size was very small. She stated in her presentation that this was somewhat rooted in the challenge of acquiring the medication for a number of patients in a timely manner due to insurance denials.
In light of that, the majority of those in the focal epilepsy group reported a reduction in their seizure frequency and did decide to continue on the medication. Hussain et al. stated their desire to follow up on this study with a larger sample size in the near future.
Cannabidiol has shown its efficacy in a number of rare epilepsies thus far, with current approvals for the treatment of both LGS and Dravet syndrome, as well as treatment of seizures associated with tuberous sclerosis complex (TSC), an indication it was granted by the FDA in August 2020.2
In September, Martina Bebin, MD, professor of neurology and pediatrics, University of Alabama at Birmingham Epilepsy Center, sat down with NeurologyLive to discuss the approval, challenges patients with TSC face, and the novelty of CBD as a therapeutic. She echoed the sentiments of Hussain et al. about the enthusiasm and interest in how the agent impacts seizures, as well as to “better understand its mechanism and what other potential benefits there might be from those CBD compounds,” continuing to say that “more and more information and better understanding of CBD and its utility in physiology is really emerging. We’re going to learn more and more as each year passes.”
For more coverage of AES 2020, click here.